Population-based linkage of health records in Western Australia: development of a health services research linked database

Long-term survival and life expectancy following an acute heart failure hospitalization in Australia and New Zealand

AIMS

Contemporary long-term survival following a heart failure (HF) hospitalization is uncertain. We evaluated survival up to 10 years after a HF hospitalization using national data from Australia and New Zealand, identified predictors of survival, and estimated the attributable loss in life expectancy.

METHODS AND RESULTS

Patients hospitalized with a primary diagnosis of HF from 2008-2017 were identified and all-cause mortality assessed by linking with Death Registries. Flexible parametric survival models were used to estimate survival, predictors of survival and loss in life expectancy. A total of 283 048 patients with HF were included (mean age 78.2 ± 12.3 years, 50.8% male). Of these, 48.3% (48.1-48.5) were surviving by 3 years, 34.1% (33.9-34.3) by 5 years and 17.1% (16.8-17.4) by 10 years (median survival 2.8 years). Survival declined with age with 53.4% of patients aged 18-54 years and 6.2% aged ≥85 years alive by 10 years (adjusted hazard ratio [aHR] for mortality 4.84, 95% confidence interval [CI] 4.65-5.04 for ≥85 years vs. 18-54 years) and was worse in male patients (aHR 1.14, 95% CI 1.13-1.15). Prior HF (aHR 1.20, 95% CI 1.18-1.22), valvular and rheumatic heart disease (aHR 1.11, 95% CI 1.10-1.13) and vascular disease (aHR 1.07, 95% CI 1.04-1.09) were cardiovascular comorbidities most strongly associated with long-term death. Non-cardiovascular comorbidities and geriatric syndromes were common and associated with higher mortality. Compared with the general population, HF was associated with a loss of 7.3 years in life expectancy (or 56.6% of the expected life expectancy) and reached 20.5 years for those aged 18-54 years.

CONCLUSION

Less than one in five patients hospitalized for HF were surviving by 10 years with patients experiencing almost 60% loss in life expectancy compared with the general population, highlighting the considerable persisting societal burden of HF. Concerted multidisciplinary efforts are needed to improve post-hospitalization outcomes of HF.

Mastering Linked Datasets: The Future of Emergency Health Care Research

Objectives: The aim of this work is to describe routine integration of prehospital emergency health records into a health master linkage file, delivering ongoing access to integrated patient treatment and outcome information for ambulance-attended patients in Queensland.Methods: The Queensland Ambulance Service (QAS) data are integrated monthly into the Queensland Health Master Linkage File (MLF) using a linkage algorithm that relies on probabilistic matches in combination with deterministic rules based on patient demographic details, date, time and facility identifiers. Each ambulance record is assigned an enduring linkage key (unique patient identifier) and further processing determines whether each record matches with a corresponding hospital emergency department, admission or death registry record. In this study, all QAS electronic ambulance report form (eARF) records from October 2016 to December 2018 where at least 1 key linkage variable was present (n = 1,771,734) were integrated into the MLF.Results: The majority of records (n = 1,456,502; 82.2%) were for transported patients, and 90.1% (n = 1,312,176) of these transports were to public hospital facilities. Of these transport records, 93.9% (n = 1,231,951) matched to emergency department (ED) records and 59.3% (n = 864,394) also linked to admitted patient records. Of ambulance non-transport records integrated into the MLF, 23.6% (n = 74,311) matched with ED records.Conclusion: This study demonstrates robust linkage methods, quality assurance processes and high linkage rates of data across the continuum of care (prehospital/emergency department/admitted patient/death) in Queensland. The resulting infrastructure provides a high-quality linked dataset that facilitates complex research and analysis to inform critical functions such as quality improvement, system evaluation and design.

The Hospital Frailty Risk Score Identifies Fewer Cases of Frailty in a Community-Based Cohort of Older Men Than the FRAIL Scale and Frailty Index

OBJECTIVES

The recently developed Hospital Frailty Risk Score (HFRS) allows ascertainment of frailty from administrative data. We aimed to compare the HFRS against the widely used FRAIL Scale and Frailty Index.

DESIGN

Population-based cohort study linked to Western Australian Hospital Morbidity Data Collection and Death Registrations.

SETTING AND PARTICIPANTS

The Health in Men Study with frailty determined at Wave 2 (2001/2004), mortality in the 1-year period following Wave 2, and disability at Wave 3 (2008). Participants were 4228 community-based men aged ≥75 years, followed until Wave 3.

MEASUREMENTS

We used multivariable regression to determine the association between each frailty measure and outcomes of length of stay (LOS), death, and disability. We also determined if the additional cases of frailty identified by one measure over the other was associated with these outcomes.

RESULTS

Of 4228 men studied, the HFRS (n = 689) identified fewer men as frail than the FRAIL Scale (n = 1648) and Frailty Index (n = 1820). In the fully adjusted models, all 3 frailty measures were associated with longer LOS and mortality, whereas only the FRAIL Scale and Frailty Index were significantly associated with disability. The additional cases of frailty identified by the FRAIL Scale and Frailty Index had longer LOS and greater risks of death and disability. The fully adjusted hazard ratio for death among the additional cases of frailty identified by the FRAIL Scale (compared to being not frail on both HFRS and FRAIL Scale) was 2.14 (95% CI 1.48-3.08).

CONCLUSIONS AND IMPLICATIONS

The HFRS is associated with adverse outcomes. However, it identified approximately 60% fewer men who were frail than the FRAIL Scale and Frailty Index, and the additional cases identified were also at high risks of adverse outcomes. Users of the HFRS should be aware of the differences with other frailty measures.

The Hospital Burden Associated With Intergenerational Contact With the Welfare System in Australia

IMPORTANCE

Intergenerational welfare contact is a policy issue because of the personal and social costs of entrenched disadvantage; yet, few studies have quantified the burden associated with intergenerational welfare contact for health.

OBJECTIVE

To examine the proportion of individuals who experienced intergenerational welfare contact and other welfare contact types and to estimate their cause-specific hospital burden.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used a whole-of-population linked administrative dataset of individuals followed from birth to age 20 years using deidentified data from the Better Evidence Better Outcomes Linked Data platform (Australian Government Centrelink [welfare payments], birth registration, perinatal birth records, and inpatient hospitalizations). Participants included individuals born in South Australia from 1991 to 1995 and their parents. Analysis was undertaken from January 2020 to June 2022.

EXPOSURES

Using Australian Government Centrelink data, welfare contact was defined as 1 or more parents receiving a means-tested welfare payment (low-income, unemployment, disability, or caring) when children were aged 11 to 15 years, or youth receiving payment at ages 16 to 20 years. Intergenerational welfare contact was defined as welfare contact occurring in both parent and offspring generations. Offspring were classified as: no welfare contact, parent-only welfare contact, offspring-only welfare contact, or intergenerational welfare contact.

MAIN OUTCOMES AND MEASURES

Hospitalization rates and cumulative incidence were estimated by age, hospitalization cause, and welfare contact group.

RESULTS

A total of 94 358 offspring (48 589 [51.5%] male) and 143 814 parents were included in analyses. The study population included 32 969 offspring (34.9%) who experienced intergenerational welfare contact. These individuals were more socioeconomically disadvantaged at birth and had the highest hospitalization rate (133.5 hospitalizations per 1000 person-years) compared with individuals with no welfare contact (46.1 hospitalizations per 1000 person-years), individuals with parent-only welfare contact (75.0 hospitalizations per 1000 person-years), and individuals with offspring-only welfare contact (87.6 hospitalizations per 1000 person-years). Hospitalizations were frequently related to injury, mental health, and pregnancy. For example, the proportion of individuals with intergenerational welfare contact who had experienced at least 1 hospitalization at ages 16 to 20 years was highest for injury (9.0% [95% CI, 8.7%-9.3%]).

CONCLUSIONS AND RELEVANCE

In this population-based cohort study, individuals who experienced intergenerational welfare contact represented one-third of the population aged 11 to 20 years. Compared with individuals with parent-only welfare contact, individuals with intergenerational welfare contact were more disadvantaged at birth and had 78% higher hospitalization rates from age 11 to 20 years, accounting for more than half of all hospitalizations. Frequent hospitalization causes were injuries, mental health, and pregnancy. This study provides the policy-relevant estimate for what it could mean to break cycles of disadvantage for reducing hospital burden.

Thirty-Day Unplanned Readmissions Following Hospitalisation for Atrial Fibrillation in Australia and New Zealand

AIMS

Atrial fibrillation (AF) is a leading cause of hospitalisations, yet little is known about 30-day readmissions following discharge despite increasing policy focus on reducing readmissions. We assessed the rate, timing, causes and predictors of 30-day unplanned readmission following an acute and elective AF hospitalisation using population-wide data.

METHODS

We studied all patients hospitalised for AF from 2010 to 2015 at all public and most private hospitals in Australia and New Zealand. The main outcome measures were unplanned readmissions within 30 days of discharge, primary diagnosis associated with these readmissions, and their predictors as modelled by logistic regression.

RESULTS

Among 301,654 patients hospitalised for AF (mean age 69.2±13.6 yrs, 55.6% female, 65.2% acute presentations), 29,750 (9.9%) experienced an unplanned readmission within 30 days with 62.6% occurring by 14 days. Unplanned readmissions occurred more frequently following an acute versus elective AF hospitalisations (12.5% vs 4.9%, p<0.001). The most common diagnoses associated with readmissions were recurrence of AF (n=9,890, 33.2%), and preventable conditions including heart failure (n=2,683, 9.0%), pneumonia (n=724, 2.4%) and acute myocardial infarction (n=510, 1.7%). A higher risk of 30-day readmission was associated with congenital cardiac/circulatory defect (OR 2.18, CI 1.44-3.30), congestive heart failure (OR 1.34, CI 1.30-1.39), and arrhythmia/conduction disorders (OR 1.25, CI 1.21-1.28).

CONCLUSION

Almost 1 in 10 AF hospitalisations resulted in unplanned readmission within 30-days, mostly for AF recurrence. Improved clinical management of AF and transitional care planning are required to reduce unplanned readmissions following AF hospitalisations.

The relationship between pancreatic cancer and type 2 diabetes: the Fremantle Diabetes Study Phase I

Pancreatic cancer incidence was double (incidence rate ratio 2.06) in community-based adults with (n = 1291) versus without (n = 5158) type 2 diabetes followed for up to 25 years in the Fremantle Diabetes Study Phase 1. Sustained higher fasting plasma glucose reflecting insulin resistance and fewer comorbidities were statistically significant risk factors in the cohort with diabetes. Past pancreatitis was an aetiologically significant determinant in the cohort as a whole.

Longitudinal risk of death, hospitalizations for atrial fibrillation, and cardiovascular events following catheter ablation of atrial fibrillation: a cohort study

AIMS

Population studies reporting contemporary long-term outcomes following catheter ablation of atrial fibrillation (AF) are sparse.We evaluated long-term clinical outcomes following AF ablation and examined variation in outcomes by age, sex, and the presence of heart failure.

METHODS AND RESULTS

We identified 30 601 unique patients (mean age 62.7 ± 11.8 years, 30.0% female) undergoing AF ablation from 2008 to 2017 in Australia and New Zealand using nationwide hospitalization data. The primary outcomes were all-cause mortality and rehospitalizations for AF or flutter, repeat AF ablation, and cardioversion. Secondary outcomes were rehospitalizations for other cardiovascular events. During 124 858.7 person-years of follow-up, 1900 patients died (incidence rate 1.5/100 person-years) with a survival probability of 93.0% (95% confidence interval (CI) 92.6-93.4%) by 5 years and 84.0% (95% CI 82.4-85.5%) by 10 years. Rehospitalizations for AF or flutter (13.3/100 person-years), repeat ablation (5.9/100 person-years), and cardioversion (4.5/100 person-years) were common, with respective cumulative incidence of 49.4% (95% CI 48.4-50.4%), 28.1% (95% CI 27.2-29.0%), and 24.4% (95% CI 21.5-27.5%) at 10 years post-ablation. Rehospitalizations for stroke (0.7/100 person-years), heart failure (1.1/100 person-years), acute myocardial infarction (0.4/100 person-years), syncope (0.6/100 person-years), other arrhythmias (2.5/100 person-years), and new cardiac device implantation (2.0/100 person-years) occurred less frequently. Elderly patients and those with comorbid heart failure had worse survival but were less likely to undergo repeat ablation, while long-term outcomes were comparable between the sexes.

CONCLUSION

Patients undergoing AF ablations had good long-term survival, a low incidence of rehospitalizations for stroke or heart failure, and about half remained free of rehospitalizations for AF or flutter, including for repeat AF ablation, or cardioversion.

Examining the intersection of child protection and public housing: development, health and justice outcomes using linked administrative data

OBJECTIVE

We described development, health and justice system outcomes for children in contact with child protection and public housing.

DESIGN

Descriptive analysis of outcomes for children known to child protection who also had contact with public housing drawn from the South Australian (SA) Better Evidence Better Outcomes Linked Data (BEBOLD) platform.

SETTING

The BEBOLD platform holds linked administrative records collected by government agencies for whole-population successive birth cohorts in SA beginning in 1999.

PARTICIPANTS

This study included data from birth registrations, perinatal, child protection, public housing, hospital, emergency department, early education and youth justice for all SA children born 1999-2013 and followed until 2016. The base population notified at least once to child protection was n=67 454.

PRIMARY OUTCOME MEASURE

Contact with the public housing system.

SECONDARY OUTCOME MEASURES

Hospitalisations and emergency department presentations before age 5, and early education at age 5, and youth justice contact before age 17.

RESULTS

More than 60% of children with at least one notification to child protection had contact with public housing, and 60.2% of those known to both systems were known to housing first. Children known to both systems experienced more emergency department and hospitalisation contacts, greater developmental vulnerability and were about six times more likely to have youth justice system contact.

CONCLUSIONS

There is substantial overlap between involvement with child protection and public housing in SA. Those children are more likely to face a life trajectory characterised by greater contact with the health system, greater early life developmental vulnerability and greater contact with the criminal justice system. Ensuring the highest quality of supportive early life infrastructure for families in public housing may contribute to prevention of contact with child protection and better life trajectories for children.

Ten-year trends in mortality and complications following catheter ablation of atrial fibrillation

AIMS

Recent US studies report rising rates of mortality and in-hospital complications following catheter ablation of atrial fibrillation (AF), but whether this is a global phenomenon is uncertain. The aim of this study was to examine trends in 30-day mortality and complications following AF ablation in Australia and New Zealand (ANZ) from 2008 to 2017.

METHODS AND RESULTS

We identified 37 243 AF (mean age 62.4 ± 11.5 years, 29.6% females, 94.5% elective procedures) ablations using national hospitalization data. The primary outcome was occurrence of any complication, including all-cause mortality, within 30 days of discharge. Trends were evaluated using logistic regression adjusting for changes in patient characteristics. The annual number of ablations increased from 1359 (2008) to 5115 (2017). Patients' age and rates of heart failure (9.8-10.6%), diabetes (6.8-12.4%), and chronic kidney disease (2.2-4.1%) also increased over time. From 2008 to 2017, the overall rate of complications declined from 7.51% to 5.04% [adjusted odds ratio (aOR) 0.96 (95% confidence interval, CI, 0.94-0.97)/year]. Rates of pericardial effusion [1.69-0.70%, aOR 0.93 (0.89-0.97)], bleeding [4.49-2.74%, aOR 0.94 (0.92-0.96)], and vascular injury [0.52-0.16%, aOR 0.91 (0.85-0.98)] declined, but rates of acute kidney injury [0.15-0.68%, aOR 1.16 (1.08-1.25)] and infection [0.15-0.57%, aOR 1.07 (1.01-1.14)] increased over time. The overall 30-day mortality rate was low (0.11%) and unchanged [0.00-0.16%, aOR 0.99 (0.88-1.11)].

CONCLUSION

Despite a five-fold increase in AF ablations and the rising risk profile of patients, complications following AF ablation declined by 30% from 2008 to 2017 in ANZ. Procedure-related death was uncommon and occurred in less than 1 in 850 patients.

Unplanned 30-day readmission, comorbidity, and impact on mortality after incident atrial fibrillation hospitalization in Western Australia, 2001–2015

Background

The healthcare burden of atrial fibrillation (AF) is dominated by hospitalizations, but data on 30-day unplanned readmissions after AF hospitalization and impact on mortality are limited.

Objective

To assess causes and trends of 30-day unplanned readmission in incident (first-ever) hospitalized AF patients, and the risk of readmission for subsequent all-cause mortality.

Methods

Patients aged 25–94 years, with an incident AF hospitalization (principal diagnosis) between 2001 and 2015, and surviving 30 days post discharge, were identified from linked Western Australian hospitalization and mortality data. Unplanned 30-day readmissions were categorized by principal diagnosis. Multivariable logistic and Cox regression analyses determined the independent predictors of readmission and the hazard ratio (HR) with 95% confidence intervals (CI) of readmission for subsequent 1-year mortality.

Results

Of 22,814 patients, 57.7% male, mean age 67.8 ± 13.8 (standard deviation) years, 9.5% experienced 1 or more 30-day unplanned readmissions, with standardized rates increasing 2.0% annually (95% CI, 1.0%–3.1%). Among all readmissions, 64.8% were cardiovascular-related, with AF (31.7%), coronary events (12.2%), and heart failure (8.5%) being the most frequent. In 30-day survivors, 4.3% died within 1 year. Patients with any cardiovascular or noncardiovascular readmission (vs none) had a multivariable-adjusted mortality HR of 2.12 (95% CI, 1.82–2.45). Coexistent comorbidities were independently associated with 30-day unplanned readmission and 1-year mortality.

Conclusion

Following incident AF hospitalization, 30-day unplanned readmissions were common, mostly cardiovascular-related, but any readmission, regardless of cause, was associated with a 2-fold higher adjusted mortality risk. Our findings also support the importance of comorbidity optimization within an integrated care pathway to reduce adverse outcomes in AF patients.

Emulating a target trial of intensive nurse home visiting in the policy-relevant population using linked administrative data

BACKGROUND

Populations willing to participate in randomized trials may not correspond well to policy-relevant target populations. Evidence of effectiveness that is complementary to randomized trials may be obtained by combining the 'target trial' causal inference framework with whole-of-population linked administrative data.

METHODS

We demonstrate this approach in an evaluation of the South Australian Family Home Visiting Program, a nurse home visiting programme targeting socially disadvantaged families. Using de-identified data from 2004-10 in the ethics-approved Better Evidence Better Outcomes Linked Data (BEBOLD) platform, we characterized the policy-relevant population and emulated a trial evaluating effects on child developmental vulnerability at 5 years (n = 4160) and academic achievement at 9 years (n = 6370). Linkage to seven health, welfare and education data sources allowed adjustment for 29 confounders using Targeted Maximum Likelihood Estimation (TMLE) with SuperLearner. Sensitivity analyses assessed robustness to analytical choices.

RESULTS

We demonstrated how the target trial framework may be used with linked administrative data to generate evidence for an intervention as it is delivered in practice in the community in the policy-relevant target population, and considering effects on outcomes years down the track. The target trial lens also aided in understanding and limiting the increased measurement, confounding and selection bias risks arising with such data. Substantively, we did not find robust evidence of a meaningful beneficial intervention effect.

CONCLUSIONS

This approach could be a valuable avenue for generating high-quality, policy-relevant evidence that is complementary to trials, particularly when the target populations are multiply disadvantaged and less likely to participate in trials.

Institutional variation in early mortality following isolated coronary artery bypass graft surgery

BACKGROUND

Thirty-day mortality following coronary artery bypass grafting (CABG) is a widely accepted marker for quality of care. Although surgical mortality has declined, the utility of this measure to profile quality has not been questioned. We assessed the institutional variation in risk-standardised mortality rates (RSMR) following isolated CABG within Australia and New Zealand (ANZ).

METHODS

We used an administrative dataset from all public and most private hospitals across ANZ to capture all isolated CABG procedures recorded between 2010 and 2015. The primary outcome was all-cause death occurring in-hospital or within 30-days of discharge. Hospital-specific RSMRs and 95% CI were estimated using a hierarchical generalised linear model accounting for differences in patient characteristics.

RESULTS

Overall, 60,953 patients (mean age 66.1 ± 10.1y, 18.7% female) underwent an isolated CABG across 47 hospitals. The observed early mortality rate was 1.69% (n = 1029) with 81.8% of deaths recorded in-hospital. The risk-adjustment model was developed with good discrimination (C-statistic = 0.81). Following risk-adjustment, a 3.9-fold variation was observed in RSMRs among hospitals (median:1.72%, range:0.84-3.29%). Four hospitals had RSMRs significantly higher than average, and one hospital had RSMR lower than average. When in-hospital mortality alone was considered, the median in-hospital RSMR was 1.40% with a 5.6-fold variation across institutions (range:0.57-3.19%).

CONCLUSIONS

Average mortality following isolated CABG is low across ANZ. Nevertheless, in-hospital and 30-day mortality vary among hospitals, highlighting potential disparities in care quality and the enduring usefulness of 30-day mortality as an outcome measure. Clinical and policy intervention, including participating in clinical quality registries, are needed to standardise CABG care.

Mortality rates in patients with ankylosing spondylitis with and without extra-articular manifestations and co-morbidities: A retrospective cohort study

Objective

To examine the mortality rates in hospitalised patients with ankylosing spondylitis (AS), and the association of extra-articular manifestations (EAM) and co-morbidities with mortality rates.

Methods

The study was a retrospective population-based cohort study using linked administrative data of hospitalised AS patients (n=1,791) and a matched comparison group (n=8,955). Mortality data for patients were obtained from the Western Australian Death Register. The presence of EAM and co-morbidities were identified from hospital records. Mortality rates were compared between the two groups using Cox proportional hazard models, overall and stratified by a history of EAM, comorbidities and smoking status.

Results

Crude mortality rates were significantly higher in AS patients than the comparison group (HR:1.85, 95%CI:1.62-2.12) with excess mortality in the AS group associated with cardiovascular disease (HR:5.32, 95%:3.84-7.35), cancer (HR:1.68, 95%CI:1.27-2.23), external causes (HR:3.92, 95%CI:2.28-6.77) and infections (HR:25.92, 95%CI:7.50-89.56). When patients were stratified by a history of EAM, cardiovascular disease, and smoking the risk of mortality was elevated in both patients with and without each risk factor. Within patients with AS, a history of cardiovascular disease (HR:6.33, 95%CI:4.79-8.38), diabetes (HR:2.81, 95%CI:1.99-3.95), smoking (HR:1.49, 95%CI:1.18-1.89) and EAM (HR:1.62, 95%CI: 1.24–2.11) were associated with an increased risk of mortality.

Conclusion

The presence of co-morbidities, EAMs, and smoking contribute to an increased risk of all-cause mortality in hospitalised AS patients compared to the comparison group. These results support the need to prevent or reduce the occurrence of co-morbidity and smoking in AS patients.

Young people with prior health service contacts have increased risk of repeated alcohol-related harm hospitalisations

INTRODUCTION

After a first alcohol-related hospitalisation in youth, subsequent hospitalisations may demonstrate an increased risk of further alcohol-related hospitalisations, but there is no existing data on this.

METHODS

A retrospective longitudinal study between July 1992 and June 2017 using linked hospital administrative data identified 23 464 Western Australian young people [9009 (38.4%) females and 14 455 (61.6%) males], aged 12-24 years hospitalised for at least one alcohol-related harm (ARH) episode of care. Cox regression was used to estimate hazard ratios (HR) between risk factors and repeated alcohol-related hospitalisation after the first discharge for ARH.

RESULTS

Of those admitted for an alcohol-related hospitalisation (n = 23 464), 21% (n = 4996) were readmitted for ARH. This high-risk sub-group comprised 46% (n = 16 017) of the total alcohol-related admissions (n = 34 485). After the first discharge for ARH, 16% (804) of people who experienced an alcohol-related readmission were readmitted within 1 month, and 51.8% (2589) were readmitted within 12 months. At increased risk of readmission were Aboriginal people and those with prior health service contacts occurring before their first alcohol-related hospitalisation, including illicit drug hospitalisations, mental health contacts and, in a sub-analysis, emergency department presentations.

DISCUSSION AND CONCLUSIONS

The probability of a repeated ARH hospitalisation was highest in the first month after initial discharge. There is a high-risk sub-group of young people more likely to have a repeat ARH hospitalisation. This represents an opportunity to provide interventions to those most at risk of repeated ARH.

Prenatal influenza vaccination and allergic and autoimmune diseases in childhood: A longitudinal, population-based linked cohort study

BACKGROUND

Few studies have evaluated the effect of maternal influenza vaccination on the development of allergic and autoimmune diseases in children beyond 6 months of age. We aimed to investigate the association between in utero exposure to seasonal inactivated influenza vaccine (IIV) and subsequent diagnosis of allergic and autoimmune diseases.

METHODS AND FINDINGS

This longitudinal, population-based linked cohort study included 124,760 singleton, live-born children from 106,206 mothers in Western Australia (WA) born between April 2012 and July 2016, with up to 5 years of follow-up from birth. In our study cohort, 64,169 (51.4%) were male, 6,566 (5.3%) were Aboriginal and/or Torres Strait Islander children, and the mean age at the end of follow-up was 3.0 (standard deviation, 1.3) years. The exposure was receipt of seasonal IIV during pregnancy. The outcomes were diagnosis of an allergic or autoimmune disease, including asthma and anaphylaxis, identified from hospital and/or emergency department (ED) records. Inverse probability of treatment weights (IPTWs) accounted for baseline probability of vaccination by maternal age, Aboriginal and/or Torres Strait Islander status, socioeconomic status, body mass index, parity, medical conditions, pregnancy complications, prenatal smoking, and prenatal care. The models additionally adjusted for the Aboriginal and/or Torres Strait Islander status of the child. There were 14,396 (11.5%) maternally vaccinated children; 913 (6.3%) maternally vaccinated and 7,655 (6.9%) maternally unvaccinated children had a diagnosis of allergic or autoimmune disease, respectively. Overall, maternal influenza vaccination was not associated with diagnosis of an allergic or autoimmune disease (adjusted hazard ratio [aHR], 1.02; 95% confidence interval [CI], 0.95 to 1.09). In trimester-specific analyses, we identified a negative association between third trimester influenza vaccination and the diagnosis of asthma (n = 40; aHR, 0.70; 95% CI, 0.50 to 0.97) and anaphylaxis (n = 36; aHR, 0.67; 95% CI, 0.47 to 0.95).We did not capture outcomes diagnosed in a primary care setting; therefore, our findings are only generalizable to more severe events requiring hospitalization or presentation to the ED. Due to small cell sizes (i.e., <5), estimates could not be determined for all outcomes after stratification.

CONCLUSIONS

In this study, we observed no association between in utero exposure to influenza vaccine and diagnosis of allergic or autoimmune diseases. Although we identified a negative association of asthma and anaphylaxis diagnosis when seasonal IIV was administered later in pregnancy, additional studies are needed to confirm this. Overall, our findings support the safety of seasonal inactivated influenza vaccine during pregnancy in relation to allergic and autoimmune diseases in early childhood and support the continuation of current global maternal vaccine programs and policies.

Caesarean section following antepartum stillbirth in Western Australia 2010-2015: A population-based study

BACKGROUND

There is scant literature about antepartum stillbirth management but guidelines usually recommend reserving caesarean sections for exceptional circumstances. However, little is known about caesarean section rates following antepartum stillbirth in Australia.

AIMS

We aimed to describe the onset of labour, mode of birth, and use of analgesia and anaesthesia following antepartum stillbirth and to identify factors associated with caesarean section.

MATERIAL AND METHODS

In this retrospective cohort study, we used a population-based dataset of all singleton antepartum stillbirths ≥20 weeks gestation in Western Australia between 2010-2015. The overall, primary and repeat caesarean section rates for antepartum stillbirths were calculated and multivariable Poisson regression analyses were performed to identify associated factors, and to calculate relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS

This study included 634 antepartum stillbirths. Labour was spontaneous for 134 (21.1%), induced for 457 (72.1%), and 43 (6.8%) had a prelabour caesarean section. The overall, primary and repeat caesarean section rates were 8.5%, 4.6% and 23.0% respectively and increased with gestation (P trends all <0.01). Other factors associated with an increased caesarean section risk included: any placenta praevia or placental abruption, birth at a metropolitan private hospital, large-for-gestational-age birthweight, and any maternal chronic condition. During labour, the most frequently used types of analgesia were systemic narcotics (46.0%) and regional blocks (34.7%) while among those who had a caesarean section, 40.7% had a general anaesthetic.

CONCLUSIONS

In Western Australia between 2010-2015, the caesarean section rates among women with antepartum stillbirths were low, in line with current guidelines.

Patterns of recurrent preterm birth in Western Australia: A 36-year state-wide population-based study

BACKGROUND

It is known that a previous preterm birth increases the risk of a subsequent preterm birth, but a limited number of studies have examined this beyond two consecutive pregnancies.

AIMS

This study aimed to assess the risk and patterns of (recurrent) preterm birth up to the fourth pregnancy.

MATERIALS AND METHODS

We used Western Australian routinely linked population health datasets to identify women who had two or more consecutive singleton births (≥20 weeks gestation) from 1980 to 2015. A log-binomial model was used to calculate risk ratios (RRs) and 95% confidence interval (CIs) for preterm birth risk in the third and fourth deliveries by the combined outcomes of previous pregnancies.

RESULTS

We analysed 255 435 women with 651 726 births. About 7% of women had a preterm birth in the first delivery, and the rate of continuous preterm birth recurrence was 22.9% (second), 44.9% (third) and 58.5% (fourth) deliveries. The risk of preterm birth at the third delivery was highest for women with two prior indicated preterm births (RR 12.5, 95% CI: 11.3, 13.9) and for those whose first pregnancy was 32-36 weeks gestation, and second pregnancy was less than 32 weeks gestation (RR 11.8, 95% CI: 10.3, 13.5). There were similar findings for the second and fourth deliveries.

CONCLUSIONS

Our findings demonstrate that women with any prior preterm birth were at greater risk of preterm birth in subsequent pregnancies compared with women with only term births, and the risk increased with shorter gestational length, and the number of previous preterm deliveries, especially sequential ones.

Institutional Variation in 30‐Day Complications Following Catheter Ablation of Atrial Fibrillation

Background

Complications are a measure of procedural quality, yet variation in complication rates following catheter ablation of atrial fibrillation (AF) among hospitals has not been systematically examined. We examined institutional variation in the risk‐standardized 30‐day complication rates (RSCRs) following AF ablation which may suggest variation in care quality.

Methods and Results

This cohort study included all patients >18 years old undergoing AF ablations from 2012 to 2017 in Australia and New Zealand. The primary outcome was procedure‐related complications occurring during the hospital stay and within 30 days of hospital discharge. We estimated the hospital‐specific risk‐standardized complication rates using a hierarchical generalized linear model. A total of 25 237 patients (mean age, 62.5±11.4 years; 30.2% women; median length of stay 1 day [interquartile range, 1–2 days]) were included. Overall, a complication occurred in 1400 (5.55%) patients (4.34% in hospital, 1.46% following discharge, and 0.25% experienced both). Bleeding (3.31%), pericardial effusion (0.74%), and infection (0.44%) were the most common complications while stroke/transient ischemic attack (0.24%), cardiorespiratory failure and shock (0.19%), and death (0.08%) occurred less frequently. Among 46 hospitals that performed ≥25 ablations during the study period, the crude complication rate varied from 0.00% to 21.43% (median, 5.74%). After adjustment for differences in patient and procedural characteristics, the median risk‐standardized complication rate was 5.50% (range, 2.89%–10.31%), with 10 hospitals being significantly different from the national average.

Conclusions

Procedure‐related complications occur in 5.55% of patients undergoing AF ablations, although the risk of complications varies 3‐fold among hospitals, which suggests potential disparities in care quality and the need for efforts to standardize AF ablation practices among hospitals.

Trends and burden of diabetes in pregnancy among Aboriginal and non-Aboriginal mothers in Western Australia, 1998-2015

Background

Diabetes in pregnancy (DIP), which includes pre-gestational and gestational diabetes, is more prevalent among Aboriginal women. DIP and its adverse neonatal outcomes are associated with diabetes and cardiovascular disease in the offspring. This study investigated the impact of DIP on trends of large for gestational age (LGA) in Aboriginal and non-Aboriginal populations, and added to the limited evidence on temporal trends of DIP burden in these populations.

Methods

We conducted a retrospective cohort study that included all births in Western Australia between 1998 and 2015 using linked population health datasets. Time trends of age-standardised and crude rates of pre-gestational and gestational diabetes were estimated in Aboriginal and non-Aboriginal mothers. Mixed-effects multivariable logistic regression was used to estimate the association between DIP and population LGA trends over time.

Results

Over the study period, there were 526,319 births in Western Australia, of which 6.4% were to Aboriginal mothers. The age-standardised annual rates of pre-gestational diabetes among Aboriginal mothers rose from 4.3% in 1998 to 5.4% in 2015 and remained below 1% in non-Aboriginal women. The comparable rates for gestational diabetes increased from 6.7 to 11.5% over the study period in Aboriginal women, and from 3.5 to 10.2% among non-Aboriginal mothers. LGA rates in Aboriginal babies remained high with inconsistent and no improvement in pregnancies complicated by gestational diabetes and pre-gestational diabetes, respectively. Regression analyses showed that DIP explained a large part of the increasing LGA rates over time in Aboriginal babies.

Conclusions

There has been a substantial increase in the burden of pre-gestational diabetes (Aboriginal women) and gestational diabetes (Aboriginal and non-Aboriginal) in recent decades. DIP appears to substantially contribute to increasing trends in LGA among Aboriginal babies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12663-6.

Developing a prediction model to estimate the true burden of respiratory syncytial virus (RSV) in hospitalised children in Western Australia

Respiratory syncytial virus (RSV) is a leading cause of childhood morbidity, however there is no systematic testing in children hospitalised with respiratory symptoms. Therefore, current RSV incidence likely underestimates the true burden. We used probabilistically linked perinatal, hospital, and laboratory records of 321,825 children born in Western Australia (WA), 2000-2012. We generated a predictive model for RSV positivity in hospitalised children aged < 5 years. We applied the model to all hospitalisations in our population-based cohort to determine the true RSV incidence, and under-ascertainment fraction. The model's predictive performance was determined using cross-validated area under the receiver operating characteristic (AUROC) curve. From 321,825 hospitalisations, 37,784 were tested for RSV (22.8% positive). Predictors of RSV positivity included younger admission age, male sex, non-Aboriginal ethnicity, a diagnosis of bronchiolitis and longer hospital stay. Our model showed good predictive accuracy (AUROC: 0.87). The respective sensitivity, specificity, positive predictive value and negative predictive values were 58.4%, 92.2%, 68.6% and 88.3%. The predicted incidence rates of hospitalised RSV for children aged < 3 months was 43.7/1000 child-years (95% CI 42.1-45.4) compared with 31.7/1000 child-years (95% CI 30.3-33.1) from laboratory-confirmed RSV admissions. Findings from our study suggest that the true burden of RSV may be 30-57% higher than current estimates.

Association between craniofacial anomalies, intellectual disability and autism spectrum disorder: Western Australian population-based study

BACKGROUND

Accurate knowledge of the relationship between craniofacial anomalies (CFA), intellectual disability (ID) and autism spectrum disorder (ASD) is essential to improve services and outcomes. The aim is to describe the association between CFA, ID and ASD using linked population data.

METHODS

All births (1983-2005; n = 566,225) including CFA births (comprising orofacial clefts, craniosynostosis, craniofacial microsomia and mandibulofacial dysostosis) surviving to 5 years were identified from the birth, death, birth defects and midwives population data sets. Linked data from these data sets were followed for a minimum of 5 years from birth until 2010 in the intellectual disability database to identify ID and ASD. These associations were examined using a modified Poisson regression.

RESULTS

Prevalence of ID and ASD was higher among CFA (especially with additional anomalies) than those without [prevalence ratio 5.27, 95% CI 4.44, 6.25]. It was higher among CFA than those with other gastrointestinal and urogenital anomalies but lower than nervous system and chromosomal anomalies. Children with CFA and severe ID had a higher proportion of nervous system anomalies.

CONCLUSIONS

Findings indicate increased ID and ASD among CFA but lower than nervous system and chromosomal anomalies. This population evidence can improve early identification of ID/ASD among CFA and support service planning.

IMPACT

Our study found about one in ten children born with craniofacial anomalies (CFA) are later identified with intellectual disability (ID). Prevalence of ID among CFA was higher than those with other gastrointestinal, urogenital, and musculoskeletal birth defects but lower than those with the nervous system and chromosomal abnormalities. Most children with craniofacial anomalies have a mild-to-moderate intellectual disability with an unknown aetiology. On average, intellectual disability is identified 2 years later for children born with non-syndromic craniofacial anomalies than those with syndromic conditions. Our findings can improve the early identification of ID/ASD among CFA and support service planning.

A Demographic Profile of Mothers and Their Children Who Are Victims of Family and Domestic Violence: Using Linked Police and Hospital Admissions Data

The aim of this study was to examine the key sociodemographic characteristics of Australian mothers and their children who were victims of family and domestic violence (FDV) that resulted in the male perpetrator being criminally charged for the offense or the mother being hospitalized. A population-based retrospective cohort study using de-identified linked health and police data of mothers with children born 1987-2010 who were victims of FDV 2004-2008 was utilized. Results indicate that mothers who were identified in police data are different demographically from those identified in health data and differed again from mothers identified in both health and police data. Within Western Australia, 3% of the population identify as Aboriginal; however, 44% of mothers identified as victims in police data and 73% within the health data were Aboriginal. Of the mothers identified in police data, 30% were under 25 years of age at their first assault recorded in police data compared with 21% in those identified in both police and hospital data. Most mothers identified as victims of FDV in police data had children present at their assault (60.6%). Prevalence of FDV exposure, identified in police data, was significantly different in Aboriginal children compared with non-Aboriginal children. Aboriginal children had a 19-fold (p < .0001) increased difference in prevalence of exposure compared with their non-Aboriginal counterparts. The study reveals the challenges in identifying victims of FDV when relying on a single data source for research and highlights the need for multiple datasets when investigating FDV. The overrepresentation of Aboriginal mothers and children should be taken in the context of the long-lasting impact of colonization. As such, prevention and early intervention strategies need to be underpinned by Aboriginal communities' cultural authority.

Neonatal Outcomes of Infants Born to Pregnant Women With Substance Use Disorders: A Multilevel Analysis of Linked Data

OBJECTIVE

This study examines the associations of substance use disorders in pregnancy with a set of neonatal outcomes.

METHODS

This is a quantitative retrospective study. Three linked datasets of a 10-year period (2007-2016) from New South Wales, Australia, were examined. Pregnant women were identified positive for substance use disorders when at least one hospital admission during pregnancy or delivery had opioid-, or cannabis-, or stimulant-, or alcohol- or two or more of the four substance groups- related ICD-10-AM diagnostic code. As there was a hierarchical structure in the dataset, the adjusted odds ratio (AOR) was estimated using multilevel logistic regression.

FINDINGS

Of the 622,640 birth records, 1677 (0.27%) women had opioid-related, 1857 (0.30%) had cannabis-related, 552 (0.09%) had stimulant-related, 595 (0.10%) had alcohol-related and 591 (0.09%) had polysubstance-related ICD-10-AM diagnostic codes. There were significant relationships between opioid use in pregnancy and neonatal health outcomes including preterm birth (AOR 3.2; 95% CI 2.8, 3.7) and admission to the neonatal intensive care unit (NICU) (AOR 10.0; 95% CI 8.8, 11.3). Substance use disorders due to cannabis, stimulants, alcohol or polysubstance were significantly associated with preterm birth, low birthweight, low APGAR score and admission to NICU. Also, alcohol and polysubstance use disorders in pregnancy were found to be significantly associated with stillbirth.

CONCLUSION

Results demonstrate that substance use disorders in pregnancy are associated with an increased risk of adverse neonatal outcomes. Early identification of substance use disorders through screening and adherence to pharmacotherapy and other psychosocial interventions could improve neonatal outcomes.

Changing age-specific trends in incidence, comorbidities and mortality of hospitalised heart failure in Western Australia between 2001 and 2016

BACKGROUND

Incident heart failure (HF) hospitalisation rates in most high-income countries are stable or declining. However, HF incidence may be increasing in younger people linked to changing risk factor profiles in the general population. We examined age and sex-specific patterns of incidence, comorbidities and mortality of hospitalised HF in Western Australia (WA) between 2001 and 2016.

METHODS AND RESULTS

All WA residents aged 25-94 years, with an incident (first-ever) principal HF discharge diagnosis between 2001 and 2016 were included (n = 22,476). Poisson regression derived annual age and sex-standardised rates of incident HF and 1-year mortality overall, and by age groups (25-54, 55-74, 75-94), across the study period. Overall, the age and sex-standardised rates of incident HF increased marginally by 0.6% per year (95% confidence interval (CI), 0.3, 0.8) whereas incidence increased by 3.1% per year (95% CI, 2.2, 4.0) in the 25-54 year age-group (trend p < 0.0001). There was a high prevalence (≥15%) of obesity, diabetes mellitus, cardiomyopathy, hypertension, ischemic heart disease, atrial fibrillation, and chronic kidney disease in younger HF patients. Overall standardised 1-year mortality declined by -1.0% per year (95%CI, -0.4, -1.6), driven largely by the mortality decline in the 55-74 year age group.

CONCLUSION

Incident HF hospitalisation rates have been rising in WA since 2006, notably in individuals under 55 years. The underlying reasons require further investigation, particularly the population-attributable risk related to increasing obesity and diabetes mellitus in the general population. Rising HF incidence along with declining mortality rates portends to an increasing HF burden in the community.

The role of confounding in the association between pregnancy complications and subsequent preterm birth: a cohort study

OBJECTIVE

To estimate the degree of confounding necessary to explain the associations between complications in a first pregnancy and the subsequent risk of preterm birth.

DESIGN

Population-based cohort study.

SETTING

Western Australia.

POPULATION

Women (n = 125 473) who gave birth to their first and second singleton children between 1998 and 2015.

MAIN OUTCOME MEASURES

Relative risk (RR) of a subsequent preterm birth (<37 weeks of gestation) with complications of pre-eclampsia, placental abruption, small-for-gestational age and perinatal death (stillbirth and neonatal death within 28 days of birth). We derived e-values to determine the minimum strength of association for an unmeasured confounding factor to explain away an observed association.

RESULTS

Complications in a first pregnancy were associated with an increased risk of a subsequent preterm birth. Relative risks were significantly higher when the complication was recurrent, with the exception of first-term perinatal death. The association with subsequent preterm birth was strongest when pre-eclampsia was recurrent. The risk of subsequent preterm birth with pre-eclampsia was 11.87 (95% CI 9.52-14.79) times higher after a first term birth with pre-eclampsia, and 64.04 (95% CI 53.58-76.55) times higher after a preterm first birth with pre-eclampsia, than an uncomplicated term birth. The e-values were 23.22 and 127.58, respectively.

CONCLUSIONS

The strong associations between recurrent pre-eclampsia, placental abruption and small-for-gestational age with preterm birth supports the hypothesis of shared underlying causes that persist from pregnancy to pregnancy. High e-values suggest that recurrent confounding is unlikely, as any such unmeasured confounding factor would have to be uncharacteristically large.

TWEETABLE ABSTRACT

First pregnancy complications are associated with a higher risk of subsequent preterm birth, with evidence strongest for pregnancies complicated by pre-eclampsia.

Factors driving CT utilisation in tertiary hospitals: a decomposition analysis using linked administrative data in Western Australia

OBJECTIVES

While CT scanning plays a significant role in healthcare, its increasing use has raised concerns about inappropriate use. This study investigated factors driving the changing use of CT among people admitted to tertiary hospitals in Western Australia (WA).

DESIGN AND SETTING

A repeated cross-sectional study of CT use in WA in 2003-2005 and 2013-2015 using linked administrative heath data at the individual patient level.

PARTICIPANTS

A total of 2 375 787 tertiary hospital admissions of people aged 18 years or older.

MAIN OUTCOME MEASURE

Rate of CT scanning per 1000 hospital admissions.

METHODS

A multivariable decomposition model was used to quantify the contribution of changes in patient characteristics and changes in the probability of having a CT over the study period.

RESULTS

The rate of CT scanning increased by 112 CT scans per 1000 admissions over the study period. Changes in the distribution of the observed patient characteristics were accounted for 62.7% of the growth in CT use. However, among unplanned admissions, changes in the distribution of patient characteristics only explained 17% of the growth in CT use, the remainder being explained by changes in the probability of having a CT scan. While the relative probability of having a CT scan generally increased over time across most observed characteristics, it reduced in young adults (-2.8%), people living in the rural/remote areas (-0.8%) and people transferred from secondary hospitals (-0.8%).

CONCLUSIONS

Our study highlights potential improvements in practice towards reducing medical radiation exposure in certain high risk population. Since changes in the relative probability of having a CT scan (representing changes in scope) rather than changes in the distribution of the patient characteristics (representing changes in need) explained a major proportion of the growth in CT use, this warrants more in-depth investigations in clinical practices to better inform health policies promoting appropriate use of diagnostic imaging tests.

Incidence and causes of early unplanned readmission after hospitalisation with peripheral arterial disease in Australia and New Zealand

OBJECTIVE

To evaluate the characteristics and predictors of unplanned readmission within 30 days of hospitalisation for the treatment of peripheral arterial disease (PAD) in Australia and New Zealand.

DESIGN

Analysis of hospitalisations data in the Admitted Patient Collection for each Australian state and territory and the New Zealand National Minimum Dataset (Hospital Events).

SETTING

All public and 80% of private hospitals in Australia and New Zealand.

PARTICIPANTS

Adults (18 years or older) hospitalised with a primary or conditional secondary diagnosis of PAD during 1 January 2010 - 31 December 2015.

MAIN OUTCOME MEASURE

Rate of unplanned readmission (any cause) within 30 days of hospitalisation with PAD.

RESULTS

Of 104 979 admissions included in our analysis (mean patient age, 73.7 years; SD, 12.4 years), 9765 were followed by at least one unplanned readmission within 30 days of discharge (9.3%): 3395 within one week (34.8%) and 7828 within three weeks (80.2%). The most frequent readmission primary diagnoses were atherosclerosis (1477, 15.3%), type 2 diabetes (1057, 10.8%), and "complications of procedures not elsewhere classified" (963, 9.9%). Readmission was more frequent after acute (4830 of 26 304, 18.4%) than elective PAD hospitalisations (4935 of 78 675, 6.3%), but the readmission characteristics were similar. Factors associated with greater likelihood of readmission included acute PAD hospitalisations (odds ratio [OR], 2.04; 95% CI, 1.96-2.17), surgical intervention during the PAD hospitalisation (OR, 1.74; 95% CI, 1.64-1.84), and chronic limb-threatening ischaemia (OR, 1.55; 95% CI, 1.47-1.63).

CONCLUSION

Unplanned readmissions within 30 days of hospitalisation for PAD are often for potentially preventable reasons. Their number should be reduced to improve clinical outcomes for people with PAD.

Explainable artificial intelligence for pharmacovigilance: What features are important when predicting adverse outcomes?

BACKGROUND AND OBJECTIVE

Explainable Artificial Intelligence (XAI) has been identified as a viable method for determining the importance of features when making predictions using Machine Learning (ML) models. In this study, we created models that take an individual's health information (e.g. their drug history and comorbidities) as inputs, and predict the probability that the individual will have an Acute Coronary Syndrome (ACS) adverse outcome.

METHODS

Using XAI, we quantified the contribution that specific drugs had on these ACS predictions, thus creating an XAI-based technique for pharmacovigilance monitoring, using ACS as an example of the adverse outcome to detect. Individuals aged over 65 who were supplied Musculo-skeletal system (anatomical therapeutic chemical (ATC) class M) or Cardiovascular system (ATC class C) drugs between 1993 and 2009 were identified, and their drug histories, comorbidities, and other key features were extracted from linked Western Australian datasets. Multiple ML models were trained to predict if these individuals would have an ACS related adverse outcome (i.e., death or hospitalisation with a discharge diagnosis of ACS), and a variety of ML and XAI techniques were used to calculate which features - specifically which drugs - led to these predictions.

RESULTS

The drug dispensing features for rofecoxib and celecoxib were found to have a greater than zero contribution to ACS related adverse outcome predictions (on average), and it was found that ACS related adverse outcomes can be predicted with 72% accuracy. Furthermore, the XAI libraries LIME and SHAP were found to successfully identify both important and unimportant features, with SHAP slightly outperforming LIME.

CONCLUSIONS

ML models trained on linked administrative health datasets in tandem with XAI algorithms can successfully quantify feature importance, and with further development, could potentially be used as pharmacovigilance monitoring techniques.

Hospitalisation for systemic lupus erythematosus associates with an increased risk of mortality in Australian patients from 1980 to 2014: a longitudinal, population-level, data linkage, cohort study

Objective

Mortality rates for patients with SLE have not been reported in Australia. This study determined the association between a hospitalisation for SLE with mortality.

Methods

Population-level cohort study of patients with SLE (n=2112; 25 710 person-years) and general population comparators (controls) (n=21, 120; 280 637 person-years) identified from hospital records contained within the WA Rheumatic Disease Epidemiological Registry from 1980 to 2013. SLE was identified by ICD-9-CM: 695.4, 710.0, ICD-10-AM: L93.0, M32.0. Controls were nearest matched (10:1) for age, sex, Aboriginality and temporality. Using longitudinal linked health data, we assessed the association between a hospitalisation for SLE mortality and mortality with univariate and multivariate Cox proportional hazards and competing risks regression models.

Results

At timezero, patients with SLE were similar in age (43.96 years), with higher representation of females (85.1% vs 83.4%, p=0.038), Aboriginal Australians (7.8% vs 6.0%) and smokers (20.5% vs 13.2%). Before study entry, patients with SLE (mean lookback 9 years) had higher comorbidity accrual (Charlson Comorbidity Index ≥1 item (42.0% vs 20.5%)), especially cardiovascular disease (CVD) (44.7% vs 21.0%) and nephritis (16.4% vs 0.5%), all p<0.001. During follow-up (mean 12.5 years), 548 (26.0%) patients with SLE and 2450 (11.6%) comparators died. A hospitalisation for SLE increased the unadjusted (HR 2.42, 95% CI 2.20 to 2.65) and multivariate-adjusted risk of mortality (aHR 2.03, 95% CI 1.84 to 2.23), which reduced from 1980 to 1999 (aHR 1.42) to 2000–2014 (aHR 1.27). Females (aHR 2.11), Aboriginal Australians (aHR 3.32), socioeconomically disadvantaged (aHR 2.49), and those <40 years old (aHR 7.46) were most vulnerable. At death, patients with SLE had a higher burden of infection (aHR 4.38), CVD (aHR 2.09) and renal disease (aHR 3.43), all p<0.001.

Conclusions

A hospitalisation for SLE associated with an increased risk of mortality over the 1980–2014 period compared with the general population. The risk was especially high in younger (<40 years old), socioeconomically disadvantaged and Aboriginal Australians.

Effect of frailty on initiation of statins following incident acute coronary syndromes in patients aged ≥75 years

INTRODUCTION

Statin use for preventing recurrent acute coronary syndromes (ACS) is low in older people due to many clinical factors, including frailty. Using the recently developed hospital frailty risk score, which allows ascertainment of frailty from real-world data, we examined the association between frailty and initiation of statin treatment following incident ACS in patients aged ≥75 years. Our secondary aim was to determine whether non-initiation of statins was associated with more conservative treatment, defined as non-receipt of evidence-based medicines and/or coronary artery procedures.

METHODS

We used person-linked hospital administrative and Pharmaceutical Benefits Scheme data to identify incident ACS admissions between 2005 and 2008 in Western Australia and prescription medicine use, respectively. Outcomes were receipt of any statin, high-dose statin, beta-blockers, renin-angiotensin system inhibitors (RASI), antiplatelets and coronary artery procedures within six months of the incident ACS and were analysed using multivariable generalised linear regression models.

RESULTS

In 1,558 patients (52.4% female, mean age 82.6 years), initiation of any statin or high-dose statin decreased with increasing frailty. The adjusted risk ratios for any statin were 0.89 (95% CI: 0.82-0.97) and 0.67 (95% CI: 0.54-0.85) for the intermediate- and high-frailty categories compared with the low-frailty category, respectively. Compared with patients who received statins, those not receiving statins were less likely (p<0.001) to receive beta-blockers (80.8% vs 51.5%), RASI (86.9% vs 62.1%), antiplatelets (90.9% vs 65.1%) or a coronary artery procedure (65.9% vs 21.1%).

CONCLUSIONS

Increasing frailty is inversely associated with initiation of statins and generally leads to a more conservative approach to treatment of older patients with ACS.

Predicting Future Geographic Hotspots of Potentially Preventable Hospitalisations Using All Subset Model Selection and Repeated K-Fold Cross-Validation

Long-term future prediction of geographic areas with high rates of potentially preventable hospitalisations (PPHs) among residents, or "hotspots", is critical to ensure the effective location of place-based health service interventions. This is because such interventions are typically expensive and take time to develop, implement, and take effect, and hotspots often regress to the mean. Using spatially aggregated, longitudinal administrative health data, we introduce a method to make such predictions. The proposed method combines all subset model selection with a novel formulation of repeated k-fold cross-validation in developing optimal models. We illustrate its application predicting three-year future hotspots for four PPHs in an Australian context: type II diabetes mellitus, heart failure, chronic obstructive pulmonary disease, and "high risk foot". In these examples, optimal models are selected through maximising positive predictive value while maintaining sensitivity above a user-specified minimum threshold. We compare the model's performance to that of two alternative methods commonly used in practice, i.e., prediction of future hotspots based on either: (i) current hotspots, or (ii) past persistent hotspots. In doing so, we demonstrate favourable performance of our method, including with respect to its ability to flexibly optimise various different metrics. Accordingly, we suggest that our method might effectively be used to assist health planners predict excess future demand of health services and prioritise placement of interventions. Furthermore, it could be used to predict future hotspots of non-health events, e.g., in criminology.

The Influence of Choice of Surgical Procedure on Long-Term Survival After Cardiac Surgery

BACKGROUND

There is some interest in long-term survival after various cardiac surgical strategies, including off-pump versus on-pump coronary artery surgery (CAG), mitral valve (MV) repair versus replacement, and aortic valve (AV) bioprosthetic versus mechanical replacement.

METHODS

We studied patients older than 49 years of age, recording risk factors and surgical details at the time of surgery. We classified procedures as: MV surgery with or without concurrent grafts or valves; AV surgery with or without concurrent CAG; or isolated CAG. Follow-up was through the state death register and state-wide hospital attendance records. Risk-adjusted survival was estimated using Cox proportional hazards. Observed survival was compared to the expected age- and sex- matched population survival.

RESULTS

During a median follow-up of 14.8 years 5,807 of 11,718 patients died. The difference between observed and expected survival varied between 3.4 years for AV surgery and 9.6 years for females undergoing MV surgery. The risk-adjusted mortality hazard rate after off-pump CAG was 0.93 (95% CI 0.8-1.0, p=0.84), MV repair 0.67 (95% CI 0.6-0.8, p<0.0001), MV bioprosthesis 0.82 (95% CI 0.81 (0.6-1.0, p=0.11) and bioprosthetic AV replacement 1.02 (95% CI 0.9-1.2, p=0.82).

CONCLUSIONS

Compared to the general population, cardiac surgical patients have a shorter than expected life expectancy. We observed a survival benefit of mitral valve repair over replacement. We did not observe significant survival differences between off-pump and on-pump CAG, nor between bioprosthetic and mechanical replacement.

Linking education and hospital data in England: linkage process and quality

INTRODUCTION

Linkage of administrative data for universal state education and National Health Service (NHS) hospital care would enable research into the inter-relationships between education and health for all children in England.

OBJECTIVES

We aim to describe the linkage process and evaluate the quality of linkage of four one-year birth cohorts within the National Pupil Database (NPD) and Hospital Episode Statistics (HES).

METHODS

We used multi-step deterministic linkage algorithms to link longitudinal records from state schools to the chronology of records in the NHS Personal Demographics Service (PDS; linkage stage 1), and HES (linkage stage 2). We calculated linkage rates and compared pupil characteristics in linked and unlinked samples for each stage of linkage and each cohort (1990/91, 1996/97, 1999/00, and 2004/05).

RESULTS

Of the 2,287,671 pupil records, 2,174,601 (95%) linked to HES. Linkage rates improved over time (92% in 1990/91 to 99% in 2004/05). Ethnic minority pupils and those living in more deprived areas were less likely to be matched to hospital records, but differences in pupil characteristics between linked and unlinked samples were moderate to small.

CONCLUSION

We linked nearly all pupils to at least one hospital record. The high coverage of the linkage represents a unique opportunity for wide-scale analyses across the domains of health and education. However, missed links disproportionately affected ethnic minorities or those living in the poorest neighbourhoods: selection bias could be mitigated by increasing the quality and completeness of identifiers recorded in administrative data or the application of statistical methods that account for missed links.

HIGHLIGHTS

Longitudinal administrative records for all children attending state school and acute hospital services in England have been used for research for more than two decades, but lack of a shared unique identifier has limited scope for linkage between these databases.We applied multi-step deterministic linkage algorithms to 4 one-year cohorts of children born 1 September-31 August in 1990/91, 1996/97, 1999/00 and 2004/05. In stage 1, full names, date of birth, and postcode histories from education data in the National Pupil Database were linked to the NHS Personal Demographic Service. In stage 2, NHS number, postcode, date of birth and sex were linked to hospital records in Hospital Episode Statistics.Between 92% and 99% of school pupils linked to at least one hospital record. Ethnic minority pupils and pupils who were living in the most deprived areas were least likely to link. Ethnic minority pupils were less likely than white children to link at the first step in both algorithms.Bias due to linkage errors could lead to an underestimate of the health needs in disadvantaged groups. Improved data quality, more sensitive linkage algorithms, and/or statistical methods that account for missed links in analyses, should be considered to reduce linkage bias.

Machine learning risk prediction model for acute coronary syndrome and death from use of non-steroidal anti-inflammatory drugs in administrative data

Our aim was to investigate the usefulness of machine learning approaches on linked administrative health data at the population level in predicting older patients’ one-year risk of acute coronary syndrome and death following the use of non-steroidal anti-inflammatory drugs (NSAIDs). Patients from a Western Australian cardiovascular population who were supplied with NSAIDs between 1 Jan 2003 and 31 Dec 2004 were identified from Pharmaceutical Benefits Scheme data. Comorbidities from linked hospital admissions data and medication history were inputs. Admissions for acute coronary syndrome or death within one year from the first supply date were outputs. Machine learning classification methods were used to build models to predict ACS and death. Model performance was measured by the area under the receiver operating characteristic curve (AUC-ROC), sensitivity and specificity. There were 68,889 patients in the NSAIDs cohort with mean age 76 years and 54% were female. 1882 patients were admitted for acute coronary syndrome and 5405 patients died within one year after their first supply of NSAIDs. The multi-layer neural network, gradient boosting machine and support vector machine were applied to build various classification models. The gradient boosting machine achieved the best performance with an average AUC-ROC of 0.72 predicting ACS and 0.84 predicting death. Machine learning models applied to linked administrative data can potentially improve adverse outcome risk prediction. Further investigation of additional data and approaches are required to improve the performance for adverse outcome risk prediction.

Utilisation and safety of catheter ablation of atrial fibrillation in public and private sector hospitals

Background

Little is known about the utilisation and safety of catheter ablation of atrial fibrillation (AF) among public and private sector hospitals.

Aims

To examine the uptake of AF ablations and compare procedural safety between the sectors.

Method:

Hospitalisation data from all public and private hospitals in four large Australian states (NSW, QLD, VIC and WA) were used to identify patients undergoing AF ablation from 2012 to 17. The primary endpoint was any procedure-related complications up to 30-days post-discharge. Logistic regression was used to evaluate the association between treatment at a public hospital and risk of complications adjusting for covariates.

Results

Private hospitals performed most of the 21,654 AF ablations identified (n = 16,992, 78.5 %), on patients who were older (63.5 vs. 59.9y) but had lower rates of heart failure (7.9 % vs. 10.4 %), diabetes (10.2 % vs. 14.1 %), and chronic kidney diseases (2.4 % vs. 5.2 %) (all p < 0.001) than those treated in public hospitals. When compared with private hospitals, public hospitals had a higher crude rate of complications (7.25 % vs. 4.70 %, p < 0.001). This difference remained significant after adjustment (OR 1.74 [95 % CI 1.54–2.04]) and it occurred with both in-hospital (OR 1.83 [1.57–2.14]) and post-discharge (OR 1.39 [1.06–1.83]) complications, with certain complications including acute kidney injury (OR 5.31 [3.02–9.36]), cardiac surgery (OR 5.18 [2.19–12.27]), and pericardial effusion (OR 2.18 [1.50–3.16]).

Conclusions

Private hospitals performed most of AF ablations in Australia with a lower rate of complications when compared with public hospitals. Further investigations are needed to identify the precise mechanisms of this observed difference.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06874-7.

The Australian burden of invasive group A streptococcal disease: a narrative review

The Australian and New Zealand governments have allocated significant funding to advance efforts towards a group A Streptococcus (Strep A) vaccine. The argument for Strep A vaccine development has to date focussed on prevention of non-invasive disease (e.g. pharyngitis) and immune-mediated complications (especially rheumatic heart disease). Because of the poorer prognosis and theoretically more precisely known burden of invasive, compared to non-invasive disease, exploration of the burden of invasive Strep A disease could lend further support to the vaccine business case. This narrative review critically assesses the Australian incidence of invasive Strep A disease. Case notification data were first assessed through government sources, expressing annual incidence as cases per 100 000 population. Published literature accessed through PubMed and MEDLINE was assessed to March 2020. Where estimates could be updated by replicating reported methods with publicly available data, this was performed. Invasive Strep A disease is currently notifiable in Queensland and the Northern Territory only. The magnitude, degree of certainty and recency of estimates vary by state/territory and between sub-populations, including higher incidence among Indigenous Australians compared to non-Indigenous Australians. According to inpatient records from 2017 to 2018, the Australian incidence of invasive Strep A disease was 8.3 per 100 000. However, this is likely to be an underestimate. Preventing invasive Strep A disease is an important use for a Strep A vaccine. This narrative review highlights deficiencies in our current understanding of the Australian disease burden. These difficulties would be overcome by nationally consistent mandatory case reporting.

DNA methylation patterns within whole blood of adolescents born from assisted reproductive technology are not different from adolescents born from natural conception

STUDY QUESTION

Do the epigenome-wide DNA methylation profiles of adolescents born from ART differ from the epigenome of naturally conceived counterparts?

SUMMARY ANSWER

No significant differences in the DNA methylation profiles of adolescents born from ART [IVF or ICSI] were observed when compared to their naturally conceived, similar aged counterparts.

WHAT IS KNOWN ALREADY

Short-term and longer-term studies have investigated the general health outcomes of children born from IVF treatment, albeit without common agreement as to the cause and underlying mechanisms of these adverse health findings. Growing evidence suggests that the reported adverse health outcomes in IVF-born offspring might have underlying epigenetic mechanisms.

STUDY DESIGN, SIZE, DURATION

The Growing Up Healthy Study (GUHS) is a prospective study that recruited 303 adolescents and young adults, conceived through ART, to compare various long-term health outcomes and DNA methylation profiles with similar aged counterparts from Generation 2 from the Raine Study. GUHS assessments were conducted between 2013 and 2017. The effect of ART on DNA methylation levels of 231 adolescents mean age 15.96 ± 1.59 years (52.8% male) was compared to 1188 naturally conceived counterparts, 17.25 ± 0.58 years (50.9% male) from the Raine Study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

DNA methylation profiles from a subset of 231 adolescents (13-19.9 years) from the GUHS, generated using the Infinium Methylation Epic Bead Chip (EPIC) array were compared to 1188 profiles from the Raine Study previously measured using the Illumina 450K array. We conducted epigenome-wide association approach (EWAS) and tested for an association between the cohorts applying Firth's bias reduced logistic regression against the outcome of ART versus naturally conceived offspring. Additionally, within the GUHS cohort, we investigated differences in methylation status in fresh versus frozen embryo transfers, cause of infertility as well as IVF versus ICSI conceived offspring. Following the EWAS analysis we investigated nominally significant probes using Gene Set Enrichment Analysis (GSEA) to identify enriched biological pathways. Finally, within GUHS we compared four estimates (Horvath, Hanuum, PhenoAge [Levine], and skin Horvath) of epigenetic age and their correlation with chronological age.

MAIN RESULTS AND THE ROLE OF CHANCE

Between the two cohorts, we did not identify any DNA methylation probes that reached a Bonferroni corrected P-value < 1.24E-0.7. When comparing IVF versus ICSI conceived adolescents within the GUHS cohort, after adjustment for participant age, sex, maternal smoking, multiple births, and batch effect, three methylation probes (cg15016734, cg26744878 and cg20233073) reached a Bonferroni correction of 6.31E-08. After correcting for cell count heterogeneity, two of the aforementioned probes remained significant and an additional two probes (cg 0331628 and cg 20235051) were identified. A general trend towards hypomethylation in the ICSI offspring was observed. All four measures of epigenetic age were highly correlated with chronological age and showed no evidence of accelerated epigenetic aging within their whole blood.

LIMITATIONS, REASONS FOR CAUTION

The small sample size coupled with the use of whole blood, where epigenetic differences may occur in other tissue. This was corrected by the utilized statistical method that accounts for imbalanced sample size between groups and adjusting for cell count heterogeneity. Only a small portion of the methylome was analysed and rare individual differences may be missed.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings provide further reassurance that the effects of the ART manipulations occurring during early embryogenesis, existing in the neonatal period are indeed of a transient nature and do not persist into adolescence. However, we have not excluded that alternative epigenetic mechanisms may be at play.

STUDY FUNDING/COMPETING INTEREST(S)

This project was supported by NHMRC project Grant no. 1042269 and R.J.H. received funding support from Ferring Pharmaceuticals Pty Ltd. R.J.H. is the Medical Director of Fertility Specialists of Western Australia and a shareholder in Western IVF. He has received educational sponsorship from Merck Sharp & Dohme Corp.- Australia, Merck-Serono Australia Pty Ltd and Ferring Pharmaceuticals Pty Ltd. P.B. is the Scientific Director of Concept Fertility Centre, Subiaco, Western Australia. J.L.Y. is the Medical Director of PIVET Medical Centre, Perth, Western Australia. The remaining authors have no conflicts of interest.

Evidence-Based Decision Making 6: Administrative Databases as Secondary Data Source for Epidemiologic and Health Service Research

Health-care systems require reliable information on which to base health-care planning and make decisions, as well as to evaluate their policy impact. Administrative data, predominantly captured for non-research purposes, provide important information about health services use, expenditures, and clinical outcomes and may be used to assess quality of care. With increased digitalization and accessibility of administrative databases, this data is more readily available for health service research purposes, aiding evidence-based decision making. This chapter discusses the utility of administrative data for population-based studies of health and health care.

Alcohol-related harm in emergency departments: linking to subsequent hospitalizations to quantify under-reporting of presentations

TITLE

Alcohol-related harm in emergency departments: linking to subsequent hospitalizations to quantify under-reporting of presentations.

AIMS

To quantify the proportion of emergency department (ED) presentations that could be identified as alcohol-related when linking to a patient's subsequent hospitalization, compared with using ED data alone, and to assess that comparison according to the change in alcohol harm rates over time and potential variations within subpopulations.

DESIGN

A retrospective study using linked hospital administrative data to identify ED patients who had subsequent alcohol-related hospitalizations.

SETTING

Western Australia.

PARTICIPANTS

A total of 533 816 Western Australian young people (246 866 females and 286 950 males), aged 12-24 years.

MEASUREMENTS

Whether or not presentations of young people to ED could be identified as alcohol-related, and for those that were not, how many had a subsequent alcohol-related hospitalization. Rates and proportions of alcohol-related harm for both methods of ascertainment were estimated by sex and Aboriginality across different age groups.

FINDINGS

Alcohol-related hospitalizations that followed an initial presentation at ED allowed the identification of an additional 19 994 alcohol-related presentations (95% increase). Linking to additional hospitalization information also resulted in significant variation in alcohol-related harm trends. In particular, trends in alcohol-related ED presentations for 21-24-year-old males were stable to slightly increasing using only ED data, but decreased after linking with hospitalization data (P < 0.05). Similarly, trends among Aboriginal persons aged 21-24 shifted from increasing using only ED data to being stable in comparison to presentations using subsequent hospitalizations (P < 0.05).

CONCLUSIONS

Among young people in Western Australia, twice as many emergency department presentations could be identified as being alcohol-related using diagnosis information from subsequent hospitalizations compared with emergency department data alone. When supplemented with hospitalization data, trends in alcohol-related harm presentations become significantly different within some subpopulations compared with using emergency department presentation data alone.

Disparities in severe neonatal morbidity and mortality between Aboriginal and non-Aboriginal births in Western Australia: a decomposition analysis

BACKGROUND

The health disadvantages faced by Australian Aboriginal peoples are evidenced in early life, although few studies have focused on the reasons for population-level inequalities in more severe adverse outcomes. This study aimed to examine the scale of disparity in severe neonatal morbidity (SNM) and mortality between Aboriginal and non-Aboriginal births and quantify the relative contributions of important maternal and infant factors.

METHOD

A retrospective cohort study with singleton live births (≥32 weeks' gestation) was conducted using Western Australia linked whole population datasets, from 1999 to 2015. Aboriginal status was determined based on the mothers' self-reported ethnic origin. An Australian validated indicator was adapted to identify neonates with SNM. The Oaxaca-Blinder method was employed to calculate the contribution of each maternal and infant factor to the disparity in SNM and mortality.

RESULTS

Analyses included 425 070 births, with 15 967 (3.8%) SNM and mortality cases. The disparity in SNM and mortality between Aboriginal and non-Aboriginal births was 2.9 percentage points (95% CI 2.6 to 3.2). About 71% of this gap was explained by differences in modelled factors including maternal area of residence (23.8%), gestational age (22.2%), maternal age (7.5%) and antenatal smoking (7.2%).

CONCLUSIONS

There is a considerable disparity in SNM and mortality between Aboriginal and non-Aboriginal births in Western Australia with the majority of this related to differences in maternal sociodemographic factors, antenatal smoking and gestational age. Public health programmes targeting these factors may contribute to a reduction in early life health differentials and benefit Aboriginal population health through the life course.

Injuries in mothers hospitalised for domestic violence-related assault: a whole-population linked data study

OBJECTIVE

To retrospectively assess a cohort of mothers for characteristics of injuries that they have suffered as a result of family and domestic violence (FDV) and which have required admission to a hospital during both the intrapartum and postpartum periods.

DESIGN AND SETTING

Retrospective, whole-population linked data study of FDV in Western Australia using the Western Australia birth registry from 1990 to 2009 and Hospital Morbidity Data System records from 1970 to 2013.

MAIN OUTCOME MEASURES

Number of hospitalisations, and mode, location and type of injuries recorded, with particular focus on the head and neck area.

RESULTS

There were 11 546 hospitalisations for mothers due to FDV. 8193 hospitalisations recorded an injury code to the head and/or neck region. The upper and middle thirds of the face and scalp were areas most likely to receive superficial injuries (58.7% or 4158 admissions), followed by the mouth and oral cavity (9.7% or 687 admissions). Fracture to the mandible accounted for 479 (4.2%) admissions and was almost equal to the sum of the next three most common facial fractures (nasal, maxillary and orbital floor). Mothers more likely to be hospitalised due to a head injury from FDV included those with more than one child (OR=1.17, 95% CI 1.03 to 1.30) and those with infants (<1 year old) (OR=1.40, 95% CI 1.04 to 1.90) and young children (<7 years old) (OR=1.15, 95% CI 1.01 to 1.30).

CONCLUSIONS

FDV is a serious and ongoing problem and front-line clinicians are in need of evidence-based guidelines to recognise and assist victims of FDV. Mothers with children in their care are a particularly vulnerable group.

GENDER DIFFERENCES IN COMPLICATIONS FOLLOWING CATHETER ABLATION OF ATRIAL FIBRILLATION

AIM

Population studies that provide unbiased estimates of gender differences in risk of complications following catheter ablation of atrial fibrillation (AF) are sparse. We sought to evaluate the association of female gender and risk of complications following AF ablation in a nation-wide cohort.

METHODS AND RESULTS

We identified 35,211 patients (29.5% females) undergoing AF ablations from 2008-17 using national hospitalization data from Australia and New Zealand. The primary outcome was any procedural complication occurring up to 30-days after discharge. Logistic regression was used to adjust for differences in baseline characteristics between sexes. Compared with males, females were older (mean age 64.9 vs. 61.2 years), had higher rates of hypertension (14.0% vs. 11.6%) and hematological disorders (5.3% vs. 3.8%) and experienced a higher rate of procedural complications (6.96% vs. 5.41%) (all p<0.001). This gender disparity remained significant after adjustment (OR 1.25 [95%CI 1.14-1.38], p<0.001) and was driven by an increased risk of vascular injury (OR 1.86 [1.23-2.82], p=0.003), pericarditis (OR 1.86 [1.16-2.67], p=0.008), pericardial effusion (OR 1.71 [1.35-2.17], p< 0.001), and bleeding (OR 1.30 [1.15-1.46], p<0.001). Notably, the gender difference persisted over time (OR for the most recent period 1.19 [1.003-1.422], p=0.046) despite a declining complication rate in both men and women.

CONCLUSION

Females undergoing AF ablations experienced a 25% higher risk of procedural complications compared with males, a disparity that has persisted over time despite a falling complication rate. Efforts to reduce this gender disparity should focus on reducing the incidence of pericardial effusion, pericarditis, vascular injury, and bleeding.

Comparison of stillbirth trends over two decades in Wales, United Kingdom and Western Australia: An international retrospective cohort study

BACKGROUND

Stillbirth is a critical public health issue worldwide. While the rates in high-income countries are relatively low, there are persistent between-country disparities.

OBJECTIVES

To compare stillbirth rates and trends in Wales and the State of Western Australia (WA), Australia, and provide insights into any differences.

METHODS

In this international retrospective cohort study, we pooled population-based data collections of all births ≥24 weeks' gestation (excluding terminations for congenital anomalies) between 1993 and 2015, divided into six time periods. The stillbirth rate per 1000 births was estimated for each cohort in each time period. Multivariable Poisson regression analyses, adjusted for appropriateness of growth, socio-economic status, maternal age, and multiple birth, were performed to evaluate the interaction between cohort and time period. Relative risk (RR) and 95% confidence interval (CI) for each time period and cohort were calculated.

RESULTS

There were 767 731 births (3725 stillbirths) in Wales and 648 373 (2431 stillbirths) in WA. The overall stillbirth rate declined by 15.9% over the study period in Wales (from 5.3 in 1993-96 to 4.5 per 1000 births in 2013-15; P_trend  < .01) but by 40.4% in WA (from 4.9 to 2.9 per 1000 births in WA; P_trend  < .01). Using 1993-96 in WA as the reference group, the adjusted RRs for stillbirths at 37-38 weeks' gestation in the most recent study period (2013-15) were 0.85 (95% CI 0.64, 1.13) in Wales and 0.51 (95% CI 0.36, 0.73) in WA.

CONCLUSIONS

The stillbirth rates between Wales and WA have widened in the last two decades (especially among late-term births), although the absolute rates for both are distinctly higher than the best-performing nations. While the differences may be partly explained by timing of birth and maternal life style behaviours such as smoking, it is important to identify and ameliorate the associated risk factors to support a reduction in preventable stillbirths.

Long-term outcomes following endovascular and surgical revascularization for peripheral artery disease: a propensity score-matched analysis

AIMS

Peripheral artery disease (PAD) revascularization can be performed by either endovascular or open surgical approach. Despite increasing use of endovascular revascularization, it is still uncertain which strategy yields better long-term outcomes.

METHODS AND RESULTS

This retrospective cohort study evaluated patients hospitalized with PAD in Australia and New Zealand who underwent either endovascular or surgical revascularization between 2008 and 2015, and compared procedures using a propensity score-matched analysis. Hybrid interventions were excluded. The primary endpoint was mortality or major adverse limb events (MALE), defined as a composite endpoint of acute limb ischaemia, urgent surgical or endovascular reintervention, or major amputation, up to 8 years post-hospitalization using time-to-event analyses 75 189 patients fulfilled eligibility (15 239 surgery and 59 950 endovascular), from whom 14 339 matched pairs (mean ± SD age 71 ± 12 years, 73% male) with good covariate balance were identified. Endovascular revascularization was associated with an increase in combined MALE or mortality [hazard ratio (HR) 1.13, 95% confidence interval (CI): 1.09-1.17, P < 0.001]. There was a similar risk of MALE (HR 1.04, 95% CI: 0.99-1.10, P = 0.15), and all-cause urgent rehospitalizations (HR 1.01, 95% CI: 0.98-1.04, P = 0.57), but higher mortality (HR 1.16, 95% CI: 1.11-1.21, P < 0.001) when endovascular repair was compared to surgery. In subgroup analysis, these findings were consistent for both claudication and chronic limb-threatening ischaemia presentations.

CONCLUSION

Although the long-term risk of MALE was comparable for both approaches, enduring advantages of surgical revascularization included lower long-term mortality. This is at odds with some prior PAD studies and highlights contention in this space.

The accuracy of administrative health data for identifying patients with rheumatoid arthritis: a retrospective validation study using medical records in Western Australia

The use of administrative health datasets is increasingly important for research on disease trends and outcome. The Western Australian (WA) Rheumatic Disease Epidemiological Registry contains longitudinal health data for over 10,000 patients with rheumatoid arthritis (RA). Accurate coding for RA is essential to the validity of this dataset. Investigate the diagnostic accuracy of International Classification of Diseases (ICD)-based discharge codes for RA at WA's largest tertiary hospital. Medical records for a sample of randomly selected patients with ICD-10 codes (M05.00-M06.99) in the hospital discharge database between 2008 and 2020 were retrospectively reviewed. Rheumatologist-reported diagnoses and ACR/EULAR classification criteria were used as reference standards to determine accuracy measures. Medical chart review was completed for 87 patients (mean (± SD) age 64.7 ± 17.2 years), 67.8% female). A total of 80 (91.9%) patients had specialist confirmed RA diagnosis, while seven patients (8%) had alternate clinical diagnoses. Among 87 patients, 69 patients (79.3%) were fulfilled ACR/EULAR classification criteria. The agreement between the reference standards was moderate (Kappa 0.41). Based on rheumatologist-reported diagnoses and ACR/EULAR classification criteria, primary diagnostic codes for RA alone had a sensitivity of (90% vs 89.8%), and PPV (90.9% vs 63.6%), respectively. A combination of a diagnostic RA code with biologic infusion codes in two or more codes increased the PPV to 97.9%. Hospital discharge diagnostic codes in WA identify RA patients with a high degree of accuracy. Combining a primary diagnostic code for RA with biological infusion codes can further increase the PPV.

Assessing the Burden of Laboratory-Confirmed Respiratory Syncytial Virus Infection in a Population Cohort of Australian Children Through Record Linkage

BACKGROUND

Significant progress has been made towards an effective respiratory syncytial virus (RSV) vaccine. Age-stratified estimates of RSV burden are urgently needed for vaccine implementation. Current estimates are limited to small cohorts or clinical coding data only. We present estimates of laboratory-confirmed RSV across multiple severity levels.

METHODS

We linked laboratory, perinatal, and hospital data of 469 589 children born in Western Australia in 1996-2012. Respiratory syncytial virus tests and detections were classified into community, emergency department (ED), and hospital levels to estimate infection rates. Clinical diagnoses given to children with RSV infection presenting to ED or hospitalized were identified.

RESULTS

In 2000-2012, 10% (n = 45 699) of children were tested for RSV and 16% (n = 11 461) of these tested positive. Respiratory syncytial virus was detected in community, ED (both 0.3 per 1000 child-years), and hospital (2.4 per 1000 child-years) settings. Respiratory syncytial virus-confirmed rates were highest among children aged <3 months (31 per 1000 child-years). At least one third of children with RSV infection presenting to ED were diagnosed as other infection, other respiratory, or other (eg, agranulocytosis).

CONCLUSIONS

Respiratory syncytial virus is pervasive across multiple severity levels and diagnoses. Vaccines targeting children <3 months must be prioritized. Given that most children are never tested, estimating the under-ascertainment of RSV infection is imperative.

Exploring the association between stroke and acute myocardial infarction and statins adherence following a medicines co-payment increase

OBJECTIVES

Patient contributions (co-payments) for one months' supply of a publicly-subsidised medicine in Australia were increased by 21% in January 2005 (US$2.73-$3.31 for social security recipients and $17.05-$20.58 for others). This study investigates the relationship between patients' use of statin medication and hospitalisation for acute coronary syndrome and stroke, following this large increase in co-payments.

METHODS

We designed a retrospective cohort study of all patients in Western Australia who were dispensed statin medication between 2004 and 05. Data for the cohort was obtained from State and Federal linked databases. We divided the cohort into those who discontinued, reduced or continued statin therapy in the first six months after the co-payment increase. The primary outcome was two-year hospitalisation for acute coronary syndrome or stroke-related event. Analysis was conducted using Fine and Gray competing risk methods, with death as the competing risk.

RESULTS

There were 207,066 patients using statins prior to the co-payment increase. Following the increase, 12.5% of patients reduced their use of statin medication, 3.3% of patients discontinued therapy, and 84.2% continued therapy. There were 4343 acute coronary syndrome and stroke-related hospitalisations in the two-year follow-up period. Multivariate analysis demonstrated that discontinuing statins increased the risk of hospitalisation for acute coronary syndrome or stroke-related events by 18% (95%CI = 0.1%-40%) compared to continuing therapy. Subgroup analysis showed that men aged <70 years were at increased risk of 54-63% after discontinuing statins compared to those continuing, but that women and older men were not.

CONCLUSION

Discontinuing statin medication after a large increase patient cost contribution was associated with higher rates of acute coronary syndrome and stroke-related hospitalisation in men under 70 years. The findings highlight the importance of continued adherence to prescribed statin medication, and that discontinuing therapy for non-clinical reasons (such as cost) can possibly have negative consequences particularly for younger men.

Relative incidence and predictors of pulmonary arterial hypertension complicating type 2 diabetes: The Fremantle Diabetes Study Phase I

AIMS

To determine the relative incidence and predictors of pulmonary arterial hypertension (PAH) in type 2 diabetes.

METHODS

Hospitalizations for/with and death from/with PAH, and all-cause mortality, were ascertained from validated databases for participants from the longitudinal, community-based Fremantle Diabetes Study Phase I (FDS1; n = 1287) and age-, sex- and zip code-matched people without diabetes (n = 5153) between entry (1993-1996) and end-2017. Incidence rates (IRs) and IR ratios (IRRs) were calculated. Cox proportional hazards and competing risk models generated cause-specific (cs) and subdistribution (sd) hazard ratios (HRs) for incident PAH.

RESULTS

In the pooled cohort (mean age 64.0 years, 49% males), 49 (3.8%) of the type 2 diabetes participants and 133 (2.6%) of those without diabetes developed PAH during 106,556 person-years of follow-up (IRs (95% CI) 262 (194-346) and 151 (127-179) /100,000 person-years, respectively; IRR 1.73 (1.22-2.42), P = 0.001). Type 2 diabetes was associated with an unadjusted csHR of 1.97 (1.42-2.74) and sdHR of 1.44 (1.04-2.00) (P ≤ 0.03); after adjustment for age, sex, and co-morbidities, these were 1.43 (0.83-2.47) and 1.36 (0.97-1.91), respectively (P ≥ 0.07).

CONCLUSIONS

Type 2 diabetes is associated with an increased risk of PAH but this is no longer significant after adjustment for other explanatory variables and the competing risk of death.