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

Long-term outcomes after hospitalization for atrial fibrillation or flutter

BACKGROUND AND AIMS

Atrial fibrillation (AF) and flutter are common causes of hospitalizations but contemporary long-term outcomes following these episodes are uncertain. This study assessed outcomes up to 10 years after an acute AF or flutter hospitalization.

METHODS

Patients hospitalized acutely with a primary diagnosis of AF or flutter from 2008-17 from all public and most private hospitals in Australia and New Zealand were included. Kaplan-Meier methods and flexible parametric survival modelling were used to estimate survival and loss in life expectancy, respectively. Competing risk model accounting for death was used when estimating incidence of non-fatal outcomes.

RESULTS

A total of 260 492 adults (mean age 70.5 ± 14.4 years, 49.6% female) were followed up for 1 068 009 person-years (PY), during which 69 167 died (incidence rate 6.5/100 PY) with 91.2% survival at 1 year, 72.7% at 5 years, and 55.2% at 10 years. Estimated loss in life expectancy was 2.6 years, or 16.8% of expected life expectancy. Re-hospitalizations for heart failure (2.9/100 PY), stroke (1.7/100 PY), and myocardial infarction (1.1/100 PY) were common with respective cumulative incidences of 16.8%, 11.0%, and 7.1% by 10 years. Re-hospitalization for AF or flutter occurred in 21.3% by 1 year, 35.3% by 5 years, and 41.2% by 10 years (11.6/100 PY). The cumulative incidence of patients undergoing catheter ablation of AF was 6.5% at 10 years (1.2/100 PY).

CONCLUSIONS

Patients hospitalized for AF or flutter had high death rates with an average 2.6-year loss in life expectancy. Moreover, re-hospitalizations for AF or flutter and related outcomes such as heart failure and stroke were common with catheter ablation used infrequently for treatment, which warrant further actions.

Long-term incidence, risk factors and complications for venous thromboembolism in patients with systemic lupus erythematosus

AIM

To compare frequency, incidence rates (IR), risk factors and outcomes of a first venous thromboembolic event (VTE) between patients with systemic lupus erythematosus (SLE) and controls.

METHODS

Using state-wide longitudinal hospital data from Western Australia (WA), we recorded venous thrombosis (VT) and pulmonary embolism (PE) in patients with SLE (n = 1854, median age 40, 86% female) and matched hospitalised controls (n = 12,107, median age 40 years, females 88.6%) in the period 1985-2015. Results presented are medians, frequency, IR per 1000 person years (PY) and odds, rate, or adjusted hazard ratios (OR/RR/a-HR) with 95% confidence intervals (CI).

RESULTS

Patients with SLE had significantly higher odds (12.8 vs 3.3%; OR 4.26, CI 3.60-5.05) and IR for a first VTE (10.09 vs 1.52; RR 6.64; CI 5.56-7.79). Over the three study decades, the IR for PE declined in patients with SLE from 7.74 to 3.75/1000 PY (p < .01) with no changes observed for VT or in controls. VTE recurred more frequently in patients with SLE (24.1% vs 10.2 %) (p < .01). Antiphospholipid antibodies (aPL) (a-HR 4.24, CI 2.50-7.19), serositis (a-HR 2.70, CI 1.86-3.91), lupus nephritis (a-HR 1.75 CI 1.25-2.33) and thrombocytopenia (a-HR 1.65 (1.10-2.49) were the strongest disease risk factors for VTE only in patients with SLE, while arterial hypertension, smoking and obesity were independent VTE risk factors for both groups. VTE was not associated with an increased risk for arterial events, but PE increased the risk for pulmonary hypertension (PH) in both patients with SLE (a-HR 6.47, CI 3.73-11.23) and controls (a-HR 9.09, CI 3.50-23.63). VTE increased the risk of death in both patients with SLE (a-HR 2.02, CI 1.50-2.70) and controls (a-HR 6.63, CI 5.21-8.42) after 10 years of follow-up.

CONCLUSIONS

VTE affected 12.8% of patients with SLE at six times the VTE rate in controls with aPL as the strongest, but not the only risk factor in SLE. The risk of PH was increased in both groups following PE, but VTE did not associate with an increased risk of arterial events.

Associations between endometriosis and adverse pregnancy and perinatal outcomes: a population-based cohort study

PURPOSE

To examine the association between endometriosis and adverse pregnancy and perinatal outcomes (preeclampsia, placenta previa, and preterm birth).

METHODS

A population-based retrospective cohort study was conducted among 468,778 eligible women who contributed 912,747 singleton livebirths between 1980 and 2015 in Western Australia (WA). We used probabilistically linked perinatal and hospital separation data from the WA data linkage system's Midwives Notification System and Hospital Morbidity Data Collection databases. We used a doubly robust estimator by combining the inverse probability weighting with the outcome regression model to estimate adjusted risk ratios (RR) and 95% confidence intervals (CIs).

RESULTS

There were 19,476 singleton livebirths among 8874 women diagnosed with endometriosis. Using a doubly robust estimator, we found pregnancies in women with endometriosis to be associated with an increased risk of preeclampsia with RR of 1.18, 95% CI 1.11-1.26, placenta previa (RR 1.59, 95% CI 1.42-1.79) and preterm birth (RR 1.45, 95% CI 1.37-1.54). The observed association persisted after stratified by the use of Medically Assisted Reproduction, with a slightly elevated risk among pregnancies conceived spontaneously.

CONCLUSIONS

In this large population-based cohort, endometriosis is associated with an increased risk of preeclampsia, placenta previa, and preterm birth, independent of the use of Medically Assisted Reproduction. This may help to enhance future obstetric care among this population.

Cancer Risk and Mortality in Hospitalized Patients With Idiopathic Inflammatory Myopathies in Western Australia

OBJECTIVE

To compare cancer incidence, type, and survival between patients with idiopathic inflammatory myopathies (IIMs) in Western Australia (WA) and the general population.

METHODS

Administrative health data for hospitalized patients with incident IIM (n = 803, 56.5% female, median age 62.0 yrs), classified by a validated algorithm as polymyositis (PM; 36.2%), dermatomyositis (DM; 27.4%), inclusion body myositis (IBM; 17.1%), overlap myositis (OM; 10.7%), and other IIM (8.6%), were linked to WA cancer and death registries for the period of 1980 to 2014. Cancer incidence rates (CIRs) before and after IIM diagnosis as well as cancer mortality were compared with age-, sex-, and calendar year-matched controls (n = 3225, 54.9% female, median age 64 yrs) by rate ratios (RRs) and Kaplan-Meier survival estimates.

RESULTS

The prediagnosis CIR was similar for patients with IIM and controls (6.57 vs 5.95; RR 1.11, 95% CI 0.88-1.39) and for patients evolving to DM (n = 220) or other IIM subtypes (6.59 vs 6.56; RR 1.01, 95% CI 0.38-3.69). During follow-up, CIR was higher for all DM (4.05, 95% CI 3.04-5.29), with increased CIR for lung cancer vs controls (1.05 vs 0.33; RR 3.18, 95% CI 1.71-5.47). Cancer post diagnosis shortened life span by 59 months for patients with IIM (103 vs 162 months, P < 0.01), but reduced survival rates were observed only in patients with DM and IBM.

CONCLUSION

Cancer risk was not increased prior to IIM, but CIR for lung cancer was increased following DM diagnosis. As cancer reduced survival only in patients with DM and IBM, these data support a strategy of limited cancer screening in IIM.

Prevalence and prognostic significance of cardiac autonomic neuropathy in community-based people with type 2 diabetes: the Fremantle Diabetes Study Phase II

BACKGROUND

There is a paucity of contemporary data on the prevalence and prognostic significance of cardiac autonomic neuropathy (CAN) from community-based cohorts with type 2 diabetes assessed using gold standard methods. The aim of this study was to assess these aspects of CAN in the longitudinal observational Fremantle Diabetes Study Phase II (FDS2).

METHODS

FDS2 participants were screened at baseline using standardised cardiovascular reflex tests (CARTs) of heart rate variation during deep breathing, Valsalva manoeuvre and standing. CAN (no/possible/definite) was assessed from the number of abnormal CARTs. Multinomial regression identified independent associates of CAN status. Cox proportional hazards modelling determined independent baseline predictors of incident heart failure (HF) and ischaemic heart disease (IHD), and all-cause mortality.

RESULTS

Of 1254 participants assessed for CAN, 86 (6.9%) were outside CART age reference ranges and valid CART data were unavailable for 338 (27.0%). Of the remaining 830 (mean age 62.3 years, 55.3% males, median diabetes duration 7.3 years), 51.0%, 33.7% and 15.3% had no, possible or definite CAN, respectively. Independent associates of definite CAN (longer diabetes duration, higher body mass index and resting pulse rate, antidepressant and antihypertensive therapies, albuminuria, distal sensory polyneuropathy, prior HF) were consistent with those reported previously. In Kaplan-Meier analysis, definite CAN was associated with a lower likelihood of incident IHD and HF versus no/possible CAN (P < 0.001) and there was a graded increase in all-cause mortality risk from no CAN to possible and definite CAN (P < 0.001). When CAN category was added to the most parsimonious models, it was not a significant independent predictor of IHD (P ≥ 0.851) or HF (P ≥ 0.342). Possible CAN (hazard ratio (95% CI) 1.47 (1.01, 2.14), P = 0.046) and definite CAN (2.42 (1.60, 3.67), P < 0.001) increased the risk of all-cause mortality versus no CAN.

CONCLUSIONS

Routine screening for CAN in type 2 diabetes has limited clinical but some prognostic value.

Investigating maternal and neonatal health outcomes associated with continuing or ceasing dexamphetamine treatment for women with attention-deficit hyperactivity disorder during pregnancy: a retrospective cohort study

PURPOSE

Attention-deficit hyperactivity disorder (ADHD) is becoming more commonly diagnosed in women, consequently, more women of reproductive age are taking ADHD medication, such as dexamphetamine. However, the safety associated with continuing or ceasing dexamphetamine during pregnancy is unclear. This study investigates outcomes associated with the continuation of dexamphetamine during pregnancy compared to those who ceased or were unexposed.

METHODS

A population-based retrospective cohort of women from Western Australia who had been dispensed dexamphetamine during pregnancy and gave birth between 2003 and 2018. Women had either continued to take dexamphetamine throughout pregnancy (continuers, n = 547) or ceased dexamphetamine before the end of the second trimester (ceasers, n = 297). Additionally, a matched (1:1) comparison group of women who were dispensed an ADHD medication prior to pregnancy but not during pregnancy (unexposed) was included in the study (n = 844). Multivariable generalised linear models were used to compare maternal and neonatal health outcomes.

RESULTS

Compared to continuers, ceasers had greater odds of threatened abortion (OR: 2.28; 95%CI: 1.00, 5.15; p = 0.049). The unexposed had some benefits compared to the continuers, which included lower risk of preeclampsia (OR: 0.58; 95%CI: 0.35, 0.97; p = 0.037), hypertension (OR: 0.32; 95%CI: 0.11, 0.93; p = 0.036), postpartum haemorrhage (OR: 0.57; 95%CI: 0.41, 0.80; p = 0.001), neonatal special care unit admittance (OR: 0.16; 95%CI: 0.12, 0.20; p < 0.001) and fetal distress (OR: 0.73; 95%CI: 0.54, 0.99; p = 0.042).

CONCLUSION

Continuing dexamphetamine throughout pregnancy was not associated with an increase in adverse neonatal and maternal health outcomes compared to ceasing. Ceasing dexamphetamine during pregnancy was associated with increased odds of threatened abortion compared with continuing dexamphetamine. However, this is something that requires further investigation due to the small sample size, difficulties examining timing, and the inability to examine spontaneous abortions. The unexposed showed some benefits compared to the continuers, suggesting that where possible the cessation of dexamphetamine prior to pregnancy may be advisable.

Assessing the utility of night-time presentations as a proxy for alcohol-related harm among young emergency department trauma patients

OBJECTIVE

To assess the usefulness of night-time presentations to measure alcohol-related harm (ARH) in young trauma patients, aged 12-24 years, attending Western Australian EDs.

METHODS

A retrospective longitudinal study examined alcohol-related ED presentations in Western Australia (WA; 2002-2016) among 12- to 24-year-olds. Data from the Emergency Department Data Collection, WA State Trauma Registry Database and Hospital Morbidity Data Collection were used to identify ARH through specific codes and text searches. These were compared to ARH estimates based on presentation time. Statistical analysis involved sensitivity and specificity calculations and Cox proportional hazards modelling.

RESULTS

We identified 2644 (17.8%) night-time presentations as a proxy measure of ARH among the 14 887 presentations of patients aged 12-24 years. This closely matched the 3064 (20.6%) identified as ARH through coding methods. The highest risk for an ARH presentation occurred during the night hours between 00.00 and 04.59 hours. During these hours, the risk was 4.4-5.1 times higher compared to presentations at midday (between 12.00 and 12.59 hours). However, when looking at individual patients, we observed that night-time presentations were not a strong predictor of ARH (sensitivity: 0.39; positive predictive value: 0.46).

CONCLUSIONS

Implementing targeted interventions during night hours could be beneficial in addressing ARH presentations. However, relying solely on the time of presentation as a proxy for ARH is unlikely to effectively identify ARH in young individuals. Instead, the present study emphasises the importance of implementing mandatory data collection strategies in EDs to ensure accurate measurement of ARH cases.

The burdensome logistics of data linkage in Australia - the example of a national registry for congenital heart disease

Objective Data linkage is a very powerful research tool in epidemiology, however, establishing this can be a lengthy and intensive process. This paper reports on the complex landscape of conducting data linkage projects in Australia. Methods We reviewed the processes, required documentation, and applications required to conduct multi-jurisdictional data linkage across Australia, in 2023. Results Obtaining the necessary approvals to conduct linkage will likely take nearly 2 years (estimated 730 days, including 605 days from initial submission to obtaining all ethical approvals and an estimated further 125 days for the issuance of unexpected additionally required approvals). Ethical review for linkage projects ranged from 51 to 128 days from submission to ethical approval, and applications consisted of 9-25 documents. Conclusions Major obstacles to conducting multi-jurisdictional data linkage included the complexity of the process, and substantial time and financial costs. The process was characterised by inefficiencies at several levels, reduplication, and a lack of any key accountabilities for timely performance of processes. Data linkage is an invaluable resource for epidemiological research. Further streamlining, establishing accountability, and greater collaboration between jurisdictions is needed to ensure data linkage is both accessible and feasible to researchers.

The spectrum of idiopathic inflammatory myopathies in Western Australia: epidemiological characteristics and mortality over time

To determine long term overall and subgroup specific incidence rates and associated mortality for idiopathic inflammatory myopathies (IIM) in a population wide study. We included patients hospitalised between 1980 and 2015 with incident IIM as defined by relevant diagnostic codes for dermatomyositis (DM) polymyositis (PM), inclusion body myositis (IBM), other IIM and overlap myositis (OM) in the Western Australia Health Hospital Morbidity Data Collection (n = 846). Trends over time for annual incidence rate per million population (AIR) were analysed by least square regression and Kaplan-Meier survival and mortality rates (MR)/100 person years compared with a matched control group (n = 3681). The averaged AIR for all IIM was 19 (CI 10.4-27.5) and stable over time with point prevalence reaching 205.3 (CI 185.6-226.6) per million in 2015. Over time, the AIR for DM 5.0 (CI 0.6-9.4) and IBM 3.3 (CI 0.7-9.6) was stable, while AIR decreased for PM (p < 0.01) and increased for other IIM (p < 0.01) and OM (p < 0.01). IBM patients were eldest at diagnosis (68 years, CI 59-77) with male preponderance in IBM (53.4%) and other IIM (55.8%) groups. Crude mortality (54.5 vs 41.3%), MR ratio (6.65 vs 5.91) and 5 (65.8% vs 71.6%) and 10-year (52.5% vs 58.7%) survival were all worse for IIM patients (all p < 0.05). IBM patients had highest MR (10.1; CI 8.38-12.14) and lowest 10-year survival (39.2%). While cardiovascular disease and cancer were predominant causes of death, they were proportionally lower in IIM patients, where respiratory and rheumatic disease were more frequent causes of death. While the overall incidence of IIM in WA was stable over 35 years, the spectrum of IIM has changed significantly with increases especially in other IIM and OM. The overall prognosis with IIM remains guarded with 10-year survival just over 50%.

The hidden impact of alcohol on young victims: an analysis of alcohol-related police offences resulting in hospitalisation

BACKGROUND

Alcohol-related harm (ARH) is a significant public health concern affecting young individuals, particularly those involved in alcohol-related police incidents resulting in hospitalisation. However, the impact of alcohol on young victims remains under researched. This study aimed to identify the characteristics of offenders and victims involved in these incidents, analyse the types of offences, and understand the under-ascertainment of ARH in hospital records.

METHODS

A retrospective longitudinal study of 12-24-year-olds born between 1980 and 2005 was conducted using linked data from hospital admissions, emergency department presentations, and police incident records. Alcohol-related incidents were identified based on the attending officers' opinions in the Western Australia Police's Incident Management System (IMS). Logistic and log-binomial regression were utilised to analyse the factors associated with victimisation and under-ascertainment of ARH.

RESULTS

Our study included 22,747 individuals (11,433 victims and 11,314 offenders) involved in alcohol-related police incidents, with a small majority of victims being female (53%, n = 6,074) and a large majority of offenders being male (84.3%, n = 9,532). Most victims did not receive a diagnosis of ARH (71%, n = 760). Women were 10 times more likely to have been a victim in ARH police incidents and 2 times more likely to have an undiagnosed alcohol-related hospital admission than men. Victims and offenders predominantly came from disadvantaged areas and major cities. Aboriginal individuals were overrepresented as both offenders and victims. A significant proportion of individuals experienced emergency department presentations or hospital admissions, with head injuries being the most common. Assault causing bodily harm was the most prevalent offence resulting in hospitalisation (66%, n = 2,018).

CONCLUSIONS

There is a noteworthy disparity between the quantity of hospital admissions attributed to alcohol-related incidents and the number of cases that are formally classified as ARH in the hospital system. This disparity highlights a more profound issue of substantial under-ascertainment or inadequate identification of ARH than previously acknowledged. Our findings justify the prioritisation of prevention strategies, beyond improvement in the documentation of alcohol-related hospitalisation. Considering the scale of the problem, and the underestimation of the burden of alcohol-related hospitalisation, a proportional increase in investment is necessary to achieve population-level reductions in ARH.

Long-Term Pattern and Associated Costs of Re-hospitalisations in Patients After Index Atrial Fibrillation Admission in Western Australia, 2011-2017

AIMS

This study aimed to determine total and cardiovascular-specific re-hospitalisation patterns and associated costs within 2 years of index atrial fibrillation (AF) admission in Western Australia (WA).

METHOD

Patients aged 25-94 years, surviving an index (first-in-period) AF hospitalisation (principal diagnosis) from 2011 to 2015 were identified from WA-linked administrative data and followed for 2 years. Person-level hospitalisation costs ($ Australian dollar) were computed using the Australian Refined Diagnosis Related Groups and presented as median with first and third quartile costs.

RESULTS

The cohort comprised 17,080 patients, 59.0% men, mean age 69.6±13.3 (standard deviation) years, and 59.0% had a CHA2DS2-VA (one point for congestive heart failure, hypertension, diabetes mellitus, vascular disease or age 65-74 years; two points for prior stroke/transient ischaemic attack or age ≥75 years) score of 2 or more. Within 2 years, 13,776 patients (80.6%) were readmitted with median of 2 (1-4) readmissions. Among total all-cause readmissions (n=54,240), 40.1% were emergent and 36.6% were cardiovascular-related, led by AF (19.5%), coronary events (5.8%), and heart failure (4.2%). The median index AF admission cost was $3,264 ($2,899-$7,649) while cardiovascular readmission costs were higher, particularly stroke ($10,732 [$4,179-23,390]), AF ablation ($7,884 [$5,283-$8,878]), and heart failure ($6,759 [$6,081-$13,146]). Average readmission costs over 2 years per person increased by $4,746 (95% confidence interval [CI] $4,459-$5,033) per unit increase in baseline CHA2DS2-VA score. The average 2-year hospitalisation costs per patient, including index admission, was $27,820 (95% CI $27,308-$28,333) and total WA costs were $475.2 million between 2011 and 2017.

CONCLUSIONS

Patients after index AF hospitalisation have a high risk of cardiovascular and other readmissions with considerable healthcare cost implications. Readmission costs increased progressively with baseline CHA2DS2-VA score. Better integrated management of AF and coexistent comorbidities is likely key to reducing readmissions and associated costs.

Excess Bed Days and Hospitalization Costs Associated With 30-Day Complications Following Catheter Ablation of Atrial Fibrillation

BACKGROUND

The incidence and type of complications following catheter ablation of atrial fibrillation have been extensively examined, but the impact associated with these complications on the length of stay and hospitalization costs is unknown.

METHODS AND RESULTS

This cohort study included 20 117 adult patients (mean age 62.6±11.4 years, 30.3% women, median length of stay 1 day [interquartile range 1-2 days]) undergoing atrial fibrillation ablation in financial years 2011 to 2017 in Australia with available cost data from the National Hospital Cost Data Collection, which determines government reimbursement of health services provided. The primary outcome was the costs associated with complications occurring up to 30 days postdischarge adjusted for inflation to 2021 Australian dollars. We used generalized linear models to estimate the increase in length of stay and cost associated with complications, adjusting for patient characteristics. Within 30 days of hospital discharge, 1151 (5.72%) patients experienced a complication with bleeding (3.35%) and pericardial effusion (0.75%) being the most common. On average, the occurrence of a complication was associated with an adjusted 3.3 (95% CI, 3.1-3.6) excess bed days of hospital care (totaling 3851 days), and a $7812 (95% CI, $6754-$8870) increase in hospitalization cost (totaling $9.0 million). Most of the total excess cost was attributable to bleeding ($3.8 million, 41.9% of total excess cost) and pericardial effusion ($1.6 million, 18.2%).

CONCLUSIONS

Complications following atrial fibrillation ablation were associated with significant increase in length of stay and hospitalization costs, most of which were attributable to bleeding and pericardial effusion. Strategies to improve procedural safety and reduce health care costs should focus on these complications.

Overweight/obesity and other predictors of gestational diabetes among Aboriginal and non-Aboriginal women in Western Australia

This population-based study investigated the association of BMI and other predictors with gestational diabetes mellitus (GDM) among Australian Aboriginal and non-Aboriginal mothers. We conducted a state-wide retrospective cohort study that included all singleton births in Western Australia (n = 134,552) between 2012 and 2015 using population health datasets linked by the Western Australian Data Linkage Branch. Associations between GDM and its predictors were estimated as adjusted relative risks (aRRs) from multivariable generalised linear models. Adjusted ratio of relative risks (aRRRs) compared RRs in Aboriginal and non-Aboriginal mothers. Adjusted population attributable fractions estimated the contribution of overweight/obesity to GDM burden, and adjusted predicted probabilities for GDM were plotted against BMI levels. The following predictors had stronger associations with GDM in Aboriginal, compared to non-Aboriginal, mothers: maternal obesity (aRR [95% CI] 3.16 [2.54-3.93]; aRRR 1.57 [1.26-1.94]), previous LGA (aRR 1.70 [1.37-2.12]; aRRR 1.41 [1.13-1.76]) and previous macrosomia (birthweight ≥ 4 kg) (aRR 1.55 [1.24-1.94]; aRRR 1.53 [1.22-1.91]). 46.1% (95% CI: 36.6-54.1) of GDM cases in Aboriginal women (23.3% in non-Aboriginal mothers, 95% CI: 21.6-25.1) were attributed to overweight/obesity. Compared to non-Aboriginal mothers, adjusted GDM probabilities were higher at all BMI levels and showed greater increase with BMI. Overweight/obesity is a key driver of GDM among Aboriginal women. Association between BMI and GDM is stronger in Aboriginal, compared to non-Aboriginal, women especially at higher BMI.

Linking health survey data with health insurance data: methodology, challenges, opportunities and recommendations for public health research. An experience from the HISlink project in Belgium

In recent years, the linkage of survey data to health administrative data has increased. This offers new opportunities for research into the use of health services and public health. Building on the HISlink use case, the linkage of Belgian Health Interview Survey (BHIS) data and Belgian Compulsory Health Insurance (BCHI) data, this paper provides an overview of the practical implementation of linking data, the outcomes in terms of a linked dataset and of the studies conducted as well as the lessons learned and recommendations for future links.Individual BHIS 2013 and 2018 data was linked to BCHI data using the national register number. The overall linkage rate was 92.3% and 94.2% for HISlink 2013 and HISlink 2018, respectively. Linked BHIS-BCHI data were used in validation studies (e.g. self-reported breast cancer screening; chronic diseases, polypharmacy), in policy-driven research (e.g., mediation effect of health literacy in the relationship between socioeconomic status and health related outcomes, and in longitudinal study (e.g. identifying predictors of nursing home admission among older BHIS participants). The linkage of both data sources combines their strengths but does not overcome all weaknesses.The availability of a national register number was an asset for HISlink. Policy-makers and researchers must take initiatives to find a better balance between the right to privacy of respondents and society's right to evidence-based information to improve health. Researchers should be aware that the procedures necessary to implement a link may have an impact on the timeliness of their research. Although some aspects of HISlink are specific to the Belgian context, we believe that some lessons learned are useful in an international context, especially for other European Union member states that collect similar data.

Use of CT, ED presentation and hospitalisations 12 months before and after a diagnosis of cancer in Western Australia: a population-based retrospective cohort study

OBJECTIVE

To examine the use of CT, emergency department (ED)-presentation and hospitalisation and in 12 months before and after a diagnosis of cancer.

DESIGN

Population-based retrospective cohort study.

SETTING

West Australian linked administrative records at individual level.

PARTICIPANTS

104 009 adults newly diagnosed with cancer in 2004-2014.

MAIN OUTCOME MEASURES

CT use, ED presentations, hospitalisations.

RESULTS

As compared with the rates in the 12th month before diagnosis, the rate of CT scans started to increase from 2 months before diagnosis with an increase in both ED presentations and hospitalisation from 1 month before the diagnosis. These rates peaked in the month of diagnosis for CT scans (477 (95% CI 471 to 482) per 1000 patients), and for hospitalisations (910 (95% CI 902 to 919) per 1000 patients), and the month prior to diagnosis for ED (181 (95% CI 178 to 184) per 1000 patients) then rapidly reduced after diagnosis but remained high for the next 12 months. While the patterns of the health services used were similar between 2004 and 2014, the rate of the health services used during after diagnosis was higher in 2014 versus 2004 except for CT use in patients with lymphohaematopoietic cancer with a significant reduction.

CONCLUSION

Our results showed an increase in demand for health services from 2 months before diagnosis of cancer. Increasing use of health services during and post cancer diagnosis may warrant further investigation to identify factors driving this change.

The impact of diabetes during pregnancy on neonatal outcomes among the Aboriginal population in Western Australia: a whole-population study

BACKGROUND

Aboriginal and Torres Strait Islander (hereafter Aboriginal) women have a high prevalence of diabetes in pregnancy (DIP), which includes pre-gestational diabetes mellitus (PGDM) and gestational diabetes mellitus (GDM). We aimed to characterize the impact of DIP in babies born to Aboriginal mothers.

METHODS

A retrospective cohort study, using routinely collected linked health data that included all singleton births (N = 510 761) in Western Australia between 1998 and 2015. Stratified by Aboriginal status, generalized linear mixed models quantified the impact of DIP on neonatal outcomes, estimating relative risks (RRs) with 95% CIs. Ratio of RRs (RRRs) examined whether RRs differed between Aboriginal and non-Aboriginal populations.

RESULTS

Exposure to DIP increased the risk of adverse outcomes to a greater extent in Aboriginal babies. PGDM heightened the risk of large for gestational age (LGA) (RR: 4.10, 95% CI: 3.56-4.72; RRR: 1.25, 95% CI: 1.09-1.43), macrosomia (RR: 2.03, 95% CI: 1.67-2.48; RRR: 1.39, 95% CI: 1.14-1.69), shoulder dystocia (RR: 4.51, 95% CI: 3.14-6.49; RRR: 2.19, 95% CI: 1.44-3.33) and major congenital anomalies (RR: 2.14, 95% CI: 1.68-2.74; RRR: 1.62, 95% CI: 1.24-2.10). GDM increased the risk of LGA (RR: 2.63, 95% CI: 2.36-2.94; RRR: 2.00, 95% CI: 1.80-2.22), macrosomia (RR: 1.95, 95% CI: 1.72-2.21; RRR: 2.27, 95% CI: 2.01-2.56) and shoulder dystocia (RR: 2.78, 95% CI: 2.12-3.63; RRR: 2.11, 95% CI: 1.61-2.77). Birthweight mediated about half of the DIP effect on shoulder dystocia only in the Aboriginal babies.

CONCLUSIONS

DIP differentially increased the risks of fetal overgrowth, shoulder dystocia and congenital anomalies in Aboriginal babies. Improving care for Aboriginal women with diabetes and further research on preventing shoulder dystocia among these women can reduce the disparities.

Reproductive and sexual health of Australian adolescents exposed to family and domestic violence

BACKGROUND

There is a dearth of research investigating sexually transmitted infections (STIs) in children exposed to family and domestic violence (FDV). Further, there is no research on terminations of pregnancy in children exposed to FDV.

METHODS

This retrospective cohort study used linked administrative data from Western Australia to investigate whether exposure to FDV is associated with a risk of hospitalisations for STIs and terminations of pregnancy in adolescents. This study involved children born from 1987 to 2010 whose mother was a victim of FDV. Identification of family and domestic violence was from two sources: police and hospital records. This approach provided an exposed cohort of 16 356 and a non-exposed cohort of 41 996. Dependant variables were hospitalisations for pregnancy terminations and STIs in children aged from 13 up to 18 years of age. The primary explanatory variable was exposure to FDV. Multivariable Cox regression was used to investigate the association of FDV exposure and the outcomes.

RESULTS

Following adjustment for sociodemographic and clinical factors, children exposed to FDV had an increased risk of hospitalisations for STIs (HR 1.49, 95% CI 1.15 to 1.92) and terminations of pregnancy (HR 1.34, 95% CI 1.09 to 1.63) as an adolescent than non-exposed peers.

CONCLUSION

Children exposed to FDV are at an increased risk of hospitalisation for STI and termination of pregnancy as an adolescent. Effective interventions are needed to support children exposed to FDV.

Does OSA Increase Risk for Cancer?: A Large Historical Sleep Clinic Cohort Study

BACKGROUND

The relationship between OSA and cancer is unclear.

RESEARCH QUESTION

What is the association between OSA and cancer prevalence and incidence in a large Western Australian sleep clinic cohort (N = 20,289)?

STUDY DESIGN AND METHODS

OSA severity was defined by apnea-hypopnea index (AHI) and nocturnal hypoxemia (duration and percentage at oxygen saturation < 90%) measured by in-laboratory polysomnogram. Measures of potential confounding included age, sex, BMI, smoking status, socioeconomic status, and BP. Outcomes were determined from the Western Australian cancer and death registries. Analyses were confined within periods using consistent AHI scoring criteria: January 1, 1989, to July 31, 2002 (American Sleep Disorders Association criteria), and August 1, 2002, to June 30, 2013 (Chicago criteria). We examined associations of AHI and nocturnal hypoxemia with cancer prevalence using logistic regression and cancer incidence using Cox regression analyses.

RESULTS

Cancer prevalence at baseline was 329 of 10,561 in the American Sleep Disorders Association period and 633 of 9,728 in the Chicago period. Nocturnal hypoxemia but not AHI was independently associated with prevalent cancer following adjustment for participant age, sex, BMI, smoking status, socioeconomic status, and BP. Of those without prevalent cancer, cancer was diagnosed in 1,950 of 10,232 (American Sleep Disorders Association) and 623 of 9,095 (Chicago) participants over a median follow-up of 11.2 years. Compared with the reference category (no OSA, AHI < 5 events per hour), univariable models estimated higher hazard ratios for cancer incidence for mild (AHI 5-15 events per hour), moderate (AHI 15.1-30 events per hour), and severe (AHI > 30 events per hour) OSA. Multivariable analyses consistently revealed associations between age and, in some cases, sex, BMI, and smoking status, with cancer incidence. After adjusting for confounders, multivariable models showed no independent association between OSA severity and increased cancer incidence.

INTERPRETATION

Nocturnal hypoxemia is independently associated with prevalent cancer. OSA severity is associated with incident cancer, although this association seems secondary to other risk factors for cancer development. OSA is not an independent risk factor for cancer incidence.

Predicting liver-related events in NAFLD: A predictive model

BACKGROUND AND AIMS

Management of NAFLD involves noninvasive prediction of fibrosis, which is a surrogate for patient outcomes. We aimed to develop and validate a model predictive of liver-related events (LREs) of decompensation and/or HCC and compare its accuracy with fibrosis models.

APPROACH AND RESULTS

Patients with NAFLD from Australia and Spain who were followed for up to 28 years formed derivation (n = 584) and validation (n = 477) cohorts. Competing risk regression and information criteria were used for model development. Accuracy was compared with fibrosis models using time-dependent AUC analysis. During follow-up, LREs occurred in 52 (9%) and 11 (2.3%) patients in derivation and validation cohorts, respectively. Age, type 2 diabetes, albumin, bilirubin, platelet count, and international normalized ratio were independent predictors of LRE and were combined into a model [NAFLD outcomes score (NOS)]. The NOS model calibrated well [calibration slope, 0.99 (derivation), 0.98 (validation)] with excellent overall performance [integrated Brier score, 0.07 (derivation) and 0.01 (validation)]. A cutoff ≥1.3 identified subjects at a higher risk of LRE, (sub-HR 24.6, p < 0.001, 5-year cumulative incidence 38% vs 1.0%, respectively). The predictive accuracy at 5 and 10 years was excellent in both derivation (time-dependent AUC,0.92 and 0.90, respectively) and validation cohorts (time-dependent AUC,0.80 and 0.82, respectively). The NOS was more accurate than the fibrosis-4 or NAFLD fibrosis score for predicting LREs at 5 and 10 years ( p < 0.001).

CONCLUSIONS

The NOS model consists of readily available measures and has greater accuracy in predicting outcomes in patients with NAFLD than existing fibrosis models.

Severe maternal morbidity following stillbirth in Western Australia 2000-2015: a population-based study

PURPOSE

There is scant literature about the management of stillbirth and the subsequent risk of severe maternal morbidity (SMM). We aimed to assess the risk of SMM associated with stillbirths compared with live births and whether this differed by the presence of maternal comorbidities.

METHODS

In this retrospective cohort study, we used a population-based dataset of all stillbirths and live births ≥ 20 weeks' gestation in Western Australia between 2000 and 2015. SMM was identified using a published Australian composite for use with routinely collected hospital morbidity data. Maternal comorbidities were identified in the Hospital Morbidity Data Collection or the Midwives Notification System using a modified Australian chronic disease composite. Multivariable Poisson regression was used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for factors associated with SMM in analyses stratified by the presence of maternal comorbidities. Singleton and multiple pregnancies were examined separately.

RESULTS

This study included 458,639 singleton births (2319 stillbirths and 456,320 live births). The adjusted RRs for SMM among stillbirths were 2.30 (95% CI 1.77, 3.00) for those without comorbidities and 4.80 (95% CI 4.11, 5.59) (Interaction P value < 0.0001) for those with comorbidities compared to live births without and with comorbidities, respectively.

CONCLUSION

In Western Australia between 2000 and 2015, mothers of stillbirths both with and without any maternal comorbidities had an increased risk of SMM compared with live births. Further investigation into why women who have had a stillbirth without any existing conditions or pregnancy complications develop SMM is warranted.

Factors Predicting Secondary Respiratory Morbidity Following Early-Life Respiratory Syncytial Virus Infections: Population-Based Cohort Study

Background

The association between early-life respiratory syncytial virus (RSV) infections and later respiratory morbidity is well established. However, there is limited evidence on factors that influence this risk. We examined sociodemographic and perinatal factors associated with later childhood respiratory morbidity requiring secondary care following exposure to a laboratory-confirmed RSV episode in the first 2 years.

Methods

We used a probabilistically linked whole-of-population-based birth cohort including 252 287 children born in Western Australia between 2000 and 2009 with follow-up to the end of 2012. Cox proportional hazards models estimated adjusted hazard ratios (aHRs) of the association of various risk factors with the first respiratory episode for asthma, wheezing, and unspecified acute lower respiratory infection beyond the age of 2 years.

Results

The analytic cohort included 4151 children with a confirmed RSV test before age 2 years. The incidence of subsequent respiratory morbidity following early-life RSV infection decreased with child age at outcome (highest incidence in 2-<4-year-olds: 41.8 per 1000 child-years; 95% CI, 37.5-46.6), increased with age at RSV infection (6-<12-month-olds: 23.6/1000 child-years; 95% CI, 19.9-27.8; 12-<24-month-olds: 22.4/1000 child-years; 95% CI, 18.2-22.7) and decreasing gestational age (50.8/1000 child-years; 95% CI, 33.5-77.2 for children born extremely preterm, <28 weeks gestation). Risk factors included age at first RSV episode (6-<12 months: aHR, 1.42; 95% CI, 1.06-1.90), extreme prematurity (<28 weeks: aHR, 2.22; 95% CI, 1.40-3.53), maternal history of asthma (aHR, 1.33; 95% CI, 1.04-1.70), and low socioeconomic index (aHR, 1.76; 95% CI, 1.03-3.00).

Conclusions

Our results suggest that in addition to preterm and young infants, children aged 12-<24 months could also be potential target groups for RSV prevention to reduce the burden of later respiratory morbidities associated with RSV.

Balance and Strength Measures are Associated With Mortality in Older Men

OBJECTIVES

As people age, rates of morbidity and mortality are heterogenous. Balance and strength performance may contribute to this, offering modifiable risk factors for mortality. We aimed to compare relationships of balance and strength performance with all-cause and cause-specific mortality.

DESIGN

The Health in Men Study, a cohort study, using wave 4 as baseline for analyses (2011-2013).

SETTING AND PARTICIPANTS

1335 older men (>65 years old), initially recruited April 1996-January 1999 in Western Australia, were included.

METHODS

Physical tests included a strength (knee extension test) and balance measure (modified Balance Outcome Measure for Elder Rehabilitation (mBOOMER) Score), derived from baseline physical assessments. Outcome measures included all-cause, cardiovascular, and cancer mortality, ascertained via the WADLS death registry. Data were analyzed using Cox proportional hazards regression models (age as analysis time, adjusted for sociodemographic data, health behaviors, and conditions).

RESULTS

Four hundred seventy-three participants died before the end of follow-up (December 17, 2017). Better performance on both the mBOOMER score and knee extension test was associated with lower likelihood of all-cause [hazard ratio (HR) 0.83, 95% CI 0.80-0.87, and HR 0.96, 95% CI 0.95-0.98, respectively] and cardiovascular mortality (HR 0.82, 95% CI 0.77-0.87, and HR 0.96, 95% CI 0.94-0.98, respectively). Better mBOOMER score performance was associated with lower likelihood of cancer mortality (HR 0.90, 95% CI 0.83-0.98) only when including participants with prior cancer.

CONCLUSIONS AND IMPLICATIONS

In summary, this study demonstrates an association of poorer performance in both strength and balance with future all-cause and cardiovascular mortality. Notably, these results clarify the relationship of balance with cause-specific mortality, with balance equaling strength as a modifiable risk factor for mortality.

Perinatal outcomes of Aboriginal women with mental health disorders

OBJECTIVE

Maternal mental disorders have been associated with adverse perinatal outcomes such as low birthweight and preterm birth, although these links have been examined rarely among Australian Aboriginal populations. We aimed to evaluate the association between maternal mental disorders and adverse perinatal outcomes among Aboriginal births.

METHODS

We used whole population-based linked data to conduct a retrospective cohort study (N = 38,592) using all Western Australia singleton Aboriginal births (1990-2015). Maternal mental disorders were identified based on the International Classification of Diseases diagnoses and grouped into six broad diagnostic categories. The perinatal outcomes evaluated were preterm birth, small for gestational age, perinatal death, major congenital anomalies, foetal distress, low birthweight and 5-minute Apgar score. We employed log-binomial/-Poisson models to calculate risk ratios and 95% confidence intervals.

RESULTS

After adjustment for sociodemographic factors and pre-existing medical conditions, having a maternal mental disorder in the five years before the birth was associated with adverse perinatal outcomes, with risk ratios (95% confidence intervals) ranging from 1.26 [1.17, 1.36] for foetal distress to 2.00 [1.87, 2.15] for low birthweight. We found similar associations for each maternal mental illness category and neonatal outcomes, with slightly stronger associations when maternal mental illnesses were reported within 1 year rather than 5 years before birth and for substance use disorder.

CONCLUSIONS

This large population-based study demonstrated an increased risk of several adverse birth outcomes among Aboriginal women with mental disorders. Holistic perinatal care, treatment and support for women with mental disorders may reduce the burden of adverse birth outcomes.

Temporal trends in chronic complications of diabetes by sex in community-based people with type 2 diabetes: the Fremantle Diabetes Study

BACKGROUND

Whether recent reductions in cardiovascular disease (CVD) events and mortality in type 2 diabetes apply equally to both sexes is largely unknown. The aim of this study was to characterize temporal changes in CVD events and related outcomes in community-based male and female Australian adults with type 2 diabetes or without known diabetes.

METHODS

Participants from the longitudinal observational Fremantle Diabetes Study Phases I (FDS1; n = 1291 recruited 1993-1996) and II (FDS2; n = 1509 recruited 2008-2011) and four age-, sex- and postcode-matched individuals without diabetes (FDS1 n = 5159; FDS2 n = 6036) were followed for first myocardial infarction, stroke, heart failure hospitalization, lower extremity amputation, CVD death and all-cause mortality. Five-year incidence rates (IRs) for males versus females in FDS1 and FDS2 were calculated, and IR ratios (IRRs) derived.

RESULTS

The FD1 and FDS2 participants were of mean age 64.0 and 65.4 years, respectively, and 48.7% and 51.8% were males. For type 2 diabetes, IRRs for all endpoints were 11-62% lower in FDS2 than FDS1 for both sexes. For participants without diabetes, IRRs were 8-56% lower in FDS2 versus FDS1 apart from stroke in females (non-significantly 41% higher). IRRs for males versus females across FDS phases were not significantly different for participants with type 2 diabetes or those without diabetes (P-values for male * FDS2 interaction ≥ 0.0.083 adjusted for age). For risk factors in participants with type 2 diabetes, greater improvements between FDS1 and FDS2 in smoking rates in males were offset by a greater reduction in systolic blood pressure in females.

CONCLUSIONS

The incidence of chronic complications in Australians with type 2 diabetes and without diabetes has fallen similarly in both sexes over recent decades, consistent with comparably improved overall CVD risk factor management.

Hospitalizations and Cost of Inpatient Care for Physical Diseases in Survivors of Childhood Cancer in Western Australia: A Longitudinal Matched Cohort Study

BACKGROUND

The long-term effects of childhood cancer are unclear in the Australian context. We examined hospitalization trends for physical diseases and estimated the associated inpatient care costs in all 5-year childhood cancer survivors (CCS) diagnosed in Western Australia (WA) from 1982 to 2014.

METHODS

Hospitalization records for 2,938 CCS and 24,792 comparisons were extracted from 1987 to 2019 (median follow-up = 12 years, min = 1, max = 32). The adjusted hazard ratio (aHR) of hospitalization with 95% confidence intervals (CI) was estimated using the Andersen-Gill model for recurrent events. The cumulative burden of hospitalizations over time was assessed using the mean cumulative count method. The adjusted mean cost of hospitalization was estimated using the generalized linear models.

RESULTS

We identified a higher risk of hospitalization for all-cause (aHR, 2.0; 95% CI, 1.8-2.2) physical disease in CCS than comparisons, with the highest risk for subsequent malignant neoplasms (aHR, 15.0; 95% CI, 11.3-19.8) and blood diseases (aHR, 6.9; 95% CI, 2.6-18.2). Characteristics associated with higher hospitalization rates included female gender, diagnosis with bone tumors, cancer diagnosis age between 5 and 9 years, multiple childhood cancer diagnoses, multiple comorbidities, higher deprivation, increased remoteness, and Indigenous status. The difference in the mean total hospitalization costs for any disease was significantly higher in survivors than comparisons (publicly funded $11,483 United States Dollar, P < 0.05).

CONCLUSIONS

The CCS population faces a significantly higher risk of physical morbidity and higher cost of hospital-based care than the comparisons.

IMPACT

Our study highlights the need for long-term follow-up healthcare services to prevent disease progression and mitigate the burden of physical morbidity on CCS and hospital services.

The lasting impact of family and domestic violence on neonatal health outcomes

OBJECTIVES

To compare the health of neonates born to women who experienced family and domestic violence (FDV) 12 months prior to birth, with the health of neonates born to women with an earlier history of FDV and women with no history of FDV.

METHODS

A retrospective cohort of women who experienced FDV within 12 months of birth (antenatal FDV [AFDV]) (n = 1230) was identified using data from the Western Australia (WA) Police Force Incident Management System and WA Hospital Morbidity Data Collection. Two comparison cohorts were used, the first including women with a history of FDV (HFDV) 12-60 months prior to birth (n = 1549) and the second with no history of FDV (NFDV) recorded (n = 3690). Hospital, birth, mortality, and congenital anomaly data were used in generalized linear models to examine and compare neonatal health outcomes.

RESULTS

Women in the AFDV group had higher proportions of factors associated with poor neonatal outcomes including smoking (42.4%), substance use (23.0%), and mental health disorders (34.8%). Neonates born to AFDV mothers had significantly higher odds of congenital anomalies (OR: 1.51, 95% CI: 1.18-1.94), low birth weight (1.74, 1.45-2.10), and preterm birth (1.48, 1.22-1.79) compared with neonates born to NFDV mother. Neonatal health outcomes in those born to AFDV women were not significantly different from those born to HFDV women.

CONCLUSIONS

Antenatal and historical FDV were associated with poor neonatal health outcomes. Additional pregnancy and social support should be offered to women who have experienced FDV during or prior to pregnancy.

Unplanned Readmissions and Long-Term Mortality Risk After Incident Heart Failure Hospitalisation in Western Australia, 2001-2015

AIMS

To investigate the frequency and predictors of unplanned readmissions after incident heart failure (HF) hospitalisation and the association between readmissions and mortality over two years.

METHODS

We performed a retrospective cohort study using Western Australian morbidity and mortality data to identify all patients, aged 25-94 years, who survived an incident (first-ever) HF hospitalisation (principal diagnosis) between 2001-2015. Ordinal logistic regression models determined the covariates independently associated with unplanned readmission(s). Cox proportional hazards models with time-varying exposures determined the hazard ratios (HR) of one or more readmissions for mortality over two years after incident HF.

RESULTS

Of 18,693 patients, 53.4% male, mean age 74.4 (standard deviation [SD] 13.6) years, 61.3% experienced 32,431 unplanned readmissions (39.7% cardiovascular-related) within two years. Leading readmission causes were HF (19.1%), respiratory diseases (12.6%), and ischaemic heart disease (9.6%). All-cause death occurred in 27.2% of the cohort, and the multivariable-adjusted mortality HR of 1 (versus 0) readmission was 2.5 (95% confidence interval [CI], 2.3-2.7) increasing to 5.0 (95% CI, 4.7-5.4) for 2+ readmissions. The adjusted mortality HR of 1 and 2+ (versus 0) HF-specific readmission was 2.0 (95% CI, 1.8-2.1) and 3.6 (95% CI, 3.2-3.9), respectively. Coexistent cardiovascular and other comorbidities were independently associated with increased readmission and mortality risk.

CONCLUSION

This study underlines the high burden of recurrent unplanned cardiovascular and other readmissions within two years after incident HF hospitalisation, and their additive adverse impact on mortality. Integrated multidisciplinary management of concomitant comorbidities, in addition to HF-targeted treatments, is necessary to improve long-term prognosis in HF patients.

Long-term exposure to low-concentration PM2.5 and heart disease in older men in Perth, Australia: The Health in Men Study

Exposure to particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5) is associated with increased risk of heart disease, but less is known about the relationship at low concentrations. This study aimed to determine the dose-response relationship between long-term PM2.5 exposure and risk of incident ischemic heart disease (IHD), incident heart failure (HF), and incident atrial fibrillation (AF) in older men living in a region with relatively low ambient air pollution.

Methods

PM2.5 exposure was estimated for 11,249 older adult males who resided in Perth, Western Australia and were recruited from 1996 to 1999. Participants were followed until 2018 for the HF and AF outcomes, and until 2017 for IHD. Cox-proportional hazards models, using age as the analysis time, and adjusting for demographic and lifestyle factors were used. PM2.5 was entered as a restricted cubic spline to model nonlinearity.

Results

We observed a mean PM2.5 concentration of 4.95 μg/m3 (SD 1.68 μg/m3) in the first year of recruitment. After excluding participants with preexisting disease and adjusting for demographic and lifestyle factors, PM2.5 exposure was associated with a trend toward increased incidence of IHD, HF, and AF, but none were statistically significant. At a PM2.5 concentration of 7 μg/m3 the hazard ratio for incident IHD was 1.04 (95% confidence interval [CI] = 0.86, 1.25) compared with the reference category of 1 μg/m3.

Conclusions

We did not observe a significant association between long-term exposure to low-concentration PM2.5 air pollution and IHD, HF, or AF.

Hospitalizations from Birth to 28 Years in a Population Cohort of Individuals Born with Five Rare Craniofacial Anomalies in Western Australia

OBJECTIVE

To describe trends, age-specific patterns, and factors influencing hospitalizations for 5 rare craniofacial anomalies (CFAs).

METHODS

Data on livebirths (1983-2010; n = 721 019) including rare CFA (craniofacial microsomia, mandibulofacial dysostosis, Pierre Robin sequence, Van der Woude syndrome, and frontonasal dysplasia), episodes of death, and demographic and perinatal factors were identified from the Western Australian Register of Developmental Anomalies, Death Registrations and Midwives Notification System. Information on incident craniofacial and noncraniofacial related admissions, length of hospital stay, and intensive care and emergency-related admissions were identified using principal diagnosis and procedural codes were extracted from the Hospital Morbidity Data Collection and linked to other data sources. Associations of hospitalizations by age groups as well as demographic and perinatal factors were expressed as incidence rate ratio (IRR).

RESULTS

The incident hospitalizations were 3 times as high for rare CFA (IRR 3.22-3.72) throughout childhood into adolescence than those without. Children with rare CFA had 3-4 times as many potentially preventable hospitalizations until 18 years of age than those without. Specifically, respiratory infections (IRR 2.13-2.35), ear infections (IRR 7.92-26.28), and oral health-related conditions contributed for most noncraniofacial admissions until the adolescence period. A greater incidence of noncraniofacial related hospitalizations was observed among Indigenous children, births with intrauterine growth restrictions, and families with high socioeconomic disadvantage.

CONCLUSIONS

Throughout childhood, individuals with rare CFA had greater hospital service use, specifically for potentially preventable conditions, than those without. These population-level findings can inform new preventive strategies and early disease management targeted toward reducing preventable hospitalizations.

Investigating local variation in disease rates within high-rate regions identified using smoothing

Exploratory disease maps are designed to identify risk factors of disease and guide appropriate responses to disease and helpseeking behaviour. However, when produced using aggregatelevel administrative units, as is standard practice, disease maps may mislead users due to the Modifiable Areal Unit Problem (MAUP). Smoothed maps of fine-resolution data mitigate the MAUP but may still obscure spatial patterns and features. To investigate these issues, we mapped rates of Mental Health- Related Emergency Department (MHED) presentations in Perth, Western Australia, in 2018/19 using Australian Bureau of Statistics (ABS) Statistical Areas Level 2 (SA2) boundaries and a recent spatial smoothing technique: the Overlay Aggregation Method (OAM). Then, we investigated local variation in rates within high-rate regions delineated using both approaches. The SA2- and OAM-based maps identified two and five high-rate regions, respectively, with the latter not conforming to SA2 boundaries. Meanwhile, both sets of high-rate regions were found to comprise a select number of localised areas with exceptionally high rates. These results demonstrate how, due to the MAUP, disease maps that are produced using aggregate-level administrative units are unreliable as a basis for delineating geographic regions of interest for targeted interventions. Instead, reliance on such maps to guide responses may compromise the efficient and equitable delivery of healthcare. Detailed investigation of local variation in rates within high-rate regions identified using both administrative units and smoothing is required to improve hypothesis generation and the design of healthcare responses.

Maternal incarceration increases the risk of self-harm but not suicide: a matched cohort study

AIMS

Children of incarcerated mothers are at increased risk of experiencing multiple adversity such as poverty, mental illness and contact with child protection services (CPS), including being taken into out of home care (OOHC). However, little is known about whether these children are at increased risk of suicide or self-harm compared to children not exposed to maternal incarceration or about the factors that may contribute to this. We aimed to investigate differences in the risk of suicide and self-harm between children exposed to maternal incarceration and those not exposed and examine how socio-demographic factors, maternal mental illness and CPS contact (with or without OOHC) may affect these outcomes.

METHODS

We used a retrospective matched cohort study design, comparing 7674 children exposed to maternal incarceration with 7674 non-exposed children. We used multivariable Cox proportional hazards regression to compare the risk of suicide and self-harm between exposed and non-exposed groups, controlling for geographical remoteness, CPS contact and maternal mental illness.

RESULTS

There was no significant difference in the rate of suicide (rate ratio [RR] = 1.49; 95% confidence interval [CI]: 0.78, 2.87) or risk of suicide (adjusted hazard ratio [aHR] = 0.92; 95% CI: 0.43, 1.96) between the two groups. However, the exposed group had a significantly higher rate of self-harm (RR = 2.83; 95% CI: 2.50, 3.21) and a significantly higher risk of self-harm (aHR = 1.74; 95% CI: 1.45, 2.09) compared to those non-exposed. CPS contact with or without OOHC was independently associated with an increased risk of self-harm for both groups.

CONCLUSION

Children exposed to maternal incarceration are at an increased risk of self-harm and should be prioritized to receive targeted, multimodal support that continues after the mother's release from prison. The association between CPS contact and self-harm warrants further research.

Evidence-based medication adherence among seniors in the first year after heart failure hospitalisation and subsequent long-term outcomes: a restricted cubic spline analysis of adherence-outcome relationships

PURPOSE

Non-adherence to heart failure (HF) medications is associated with poor outcomes. We used restricted cubic splines (RCS) to assess the continuous relationship between adherence to renin-angiotensin system inhibitors (RASI) and β-blockers and long-term outcomes in senior HF patients.

METHODS

We identified a population-based cohort of 4234 patients, aged 65-84 years, 56% male, who were hospitalised for HF in Western Australia between 2003 and 2008 and survived to 1-year post-discharge (landmark date). Adherence was calculated using the proportion of days covered (PDC) in the first year post-discharge. RCS Cox proportional-hazards models were applied to determine the relationship between adherence and all-cause death and death/HF readmission at 1 and 3 years after the landmark date.

RESULTS

RCS analysis showed a curvilinear adherence-outcome relationship for both RASI and β-blockers which was linear above PDC 60%. For each 10% increase in RASI and β-blocker adherence above this level, the adjusted hazard ratio for 1-year all-cause death fell by an average of 6.6% and 4.8% respectively (trend p < 0.05) and risk of all-cause death/HF readmission fell by 5.4% and 5.8% respectively (trend p < 0.005). Linear reductions in adjusted risk for these outcomes at PDC ≥ 60% were also seen at 3 years after landmark date (all trend p < 0.05).

CONCLUSION

RCS analysis showed that for RASI and β-blockers, there was no upper adherence level (threshold) above 60% where risk reduction did not continue to occur. Therefore, interventions should maximise adherence to these disease-modifying HF pharmacotherapies to improve long-term outcomes after hospitalised HF.

Thirty-Day Unplanned Readmissions Following Elective and Acute Percutaneous Coronary Intervention

BACKGROUND

Prior studies have reported a high rate of unplanned readmissions following acute percutaneous coronary intervention (PCI). Data outside the USA comparing 30-day unplanned readmissions following elective PCI to those who undergo acute PCI remain limited.

METHODS

Patients who underwent a PCI procedure in Australia and New Zealand between 2010 and 2015 were included. We determined the rates, causes and predictors of 30-day unplanned readmissions, as well as rates of repeat revascularisation procedures, for patients who underwent an elective or acute PCI. Predictors of readmissions were identified using logistic regression.

RESULTS

A total of 199,686 PCI encounters were included, of which 74,890 (37.5%) were elective and 124,796 (62.5%) were acute procedures. Overall, 10.6% of patients had at least one unplanned readmission within 30 days of discharge with lower rates following elective PCI (7.0%) compared to acute PCI (12.7%) (p<0.01). Non-specific chest pain was the commonest cause of readmission after elective and acute PCI, accounting for 20.7% and 21.5% of readmission diagnoses, respectively. Readmissions for acute myocardial infarction (13.0% vs 4.6%, p<0.01) and heart failure (6.5% vs 3.3%, p<0.01) were higher following acute PCI compared to elective PCI. Among readmitted patients, 16.7% had a coronary catheterisation, 12.2% had a PCI and 0.7% had coronary artery bypass surgery. Multivariable predictors of 30-day unplanned readmission included female sex and comorbidities such as heart failure, metastatic disease, chronic lung disease and renal failure (p<0.0001 for all).

CONCLUSIONS

Unplanned readmissions following elective or acute PCI are high. Clinical and quality-control measures are required to prevent avoidable readmissions in both settings.

The effect of TNF treatment uptake on incident hospital admission in Western Australia

OBJECTIVE

Treatment strategies for juvenile idiopathic arthritis (JIA) have shifted significantly over the last 20 years. We examined the effect of the introduction of government-subsidised TNF inhibitor (TNFi) treatment on incident hospitalisation for JIA.

METHODS

Western Australian (WA) hospital data were used to identify patients < 16 years hospitalised with JIA between 1990 and 2012. Changes in the number of patients with an incident hospitalisation, overall admissions and admissions for joint aspiration were examined using join-point regression TNFi dispensing data from 2002-2012 was used to describe defined daily doses (DDD)/1000 population/day.

RESULTS

We included 786 patients (59.2% girls, median age 8 years) with a first-time admission with JIA. The annual incident admission rate was 7.9 per 100,000 person-years (95%CI: 7.3, 8.4) which did not change significantly between 1990 and 2012 (annual percentage change (APC): 1.3, 95%CI: -0.3, 2.8). Annual hospital-based prevalence of JIA reached 0.72/1000 in 2012. DDD for TNFi usage rose steadily from 2003 indicating TNFi usage by 1/2700 children in 2012, while overall admission rates (APC 3.7; 95%CI: 2.3, 5.1) and admission rates for joint injections (APC 4.9%; 95%CI: 3.8, 6.0) also increased significantly in that period.

CONCLUSION

Incident inpatient admission rates for JIA were stable over a 22-year period. The uptake of TNFi was not associated with lower admission rates for JIA, due mainly to an increase in admissions for joint injection. These results indicate a notable but unexpected change in hospital-based management of JIA since the introduction of TNFi therapy in WA, where hospital-based prevalence of JIA is slightly higher than in North America.

Patterns, trends, and factors influencing hospitalizations for craniosynostosis in Western Australia. A population-based study

Understanding hospital service use among children with a diagnosis of craniosynostosis (CS) is important to improve services and outcomes. This study aimed to describe population-level trends, patterns, and factors influencing hospitalizations for craniosynostosis in Western Australia. Data on live births (1990-2010; n = 554,624) including craniosynostosis, episodes of death, demographic, and perinatal factors were identified from the midwives, birth defects, hospitalizations, and death datasets. Information on craniosynostosis and non-craniosynostosis-related admissions, cumulative length of hospital stay (cLoS), intensive care unit, and emergency department-related admissions were extracted from the hospitalization dataset and linked to other data sources. These associations were examined using negative binomial regression presented as annual percent change and associations of hospitalizations by age groups, demographic, and perinatal factors were expressed as incidence rate ratio (IRR). We found an increasing trend in incident hospitalizations but a marginal decline in cLoS for craniosynostosis over the observed study period. Perinatal conditions, feeding difficulties, nervous system anomalies, respiratory, and other infections contributed to majority of infant non-CS-related admissions.Respiratory infections accounted for about twice the number of admissions for individuals with CS (IRRs 1.94-2.34) across all observed age groups. Higher incidence of non-CS hospitalizations was observed among females, with associated anomalies, to families with highest socioeconomic disadvantage and living in remote areas of the state.   Conclusion: Marginal reduction in the cLoS for CS-related admissions observed over the 21-year period are potentially indicative of improved peri-operative care. However, higher incidence of respiratory infection-related admissions for syndromic synostosis is concerning and requires investigation.

Emergent readmission and long-term mortality risk after incident atrial fibrillation hospitalisation

OBJECTIVE

To assess the frequency and predictors of unplanned readmissions after hospitalisation for incident atrial fibrillation (AF) and the association of readmissions with mortality over 2 years.

METHODS

We performed a retrospective cohort study using Western Australian morbidity and mortality data to identify all patients, aged 25-94 years, who survived incident (first-ever) hospitalisation for AF (principal diagnosis), between 2001 and 2015. Ordinal logistic models determined the covariates independently associated with unplanned readmission(s), and Cox proportional hazards models with time-varying exposures determined the hazard ratios (HR) of one or more readmissions for mortality over 2 years after incident AF.

RESULTS

Of 22 956 patients, 57.7% male, mean age 67.9 (SD 13.8) years, 44.0% experienced 22 053 unplanned readmissions within 2 years, 50.6% being cardiovascular-related. All-cause death occurred in 8.0% of the cohort, and the multivariable-adjusted mortality HR of 1 (vs 0) readmission was 2.9 (95% CI 2.6 to 3.3), increasing to 5.6 (95% CI 5.0 to 6.5) for 3+ readmissions. First emergent readmission for AF, stroke, heart failure or myocardial infarction was independently associated with an increased hazard for mortality. Coexistent cardiovascular and other comorbidities were independently associated with increased readmission and mortality risk, whereas AF ablation was associated with reduced risk.

CONCLUSION

This study highlights the large burden of unplanned all-cause and cardiovascular-specific readmissions within 2 years after being hospitalised for incident AF and their associated adverse impact on mortality. Concomitant comorbidities are independently associated with unplanned hospitalisations and mortality, which supports integrated multidisciplinary management of comorbidities, along with AF-targeted treatments, to improve long-term outcomes in patients with AF.

Why and how we can use data linkage in oral health research: a narrative review

OBJECTIVES

Poor oral health, impacting health and wellbeing across the life-course, is a costly and wicked problem. Data (or record) linkage is the linking of different sets of data (often administrative data gathered for non-research purposes) that are matched to an individual and may include records such as medical data, housing information and sociodemographic information. It often uses population-level data or 'big data'. Data linkage provides the opportunity to analyse complex associations from different sources for total populations. The aim of the paper is to explore data linkage, how it is important for oral health research and what promise it holds for the future.

METHODS

This is a narrative review of an approach (data linkage) in oral health research.

RESULTS

Data linkage may be a powerful method for bringing together various population datasets. It has been used to explore a wide variety of topics with many varied datasets. It has substantial current and potential application in oral health research.

CONCLUSIONS

Use of population data linkage is increasing in oral health research where the approach has been very useful in exploring the complexity of oral health. It offers promise for exploring many new areas in the field.

Computed Tomography Angiography for Detection of Pulmonary Embolism in Western Australia Shows Increasing Use with Decreasing Diagnostic Yield

(1) Background: Pulmonary embolism (PE) can be fatal. Computed tomography pulmonary angiography (CTPA) can accurately diagnose PE, but it should be used only when reasonable pre-test probability exists. Overtesting with CTPA exposes patients to excess ionizing radiation and contrast media, while PE overdiagnosis leads to the treatment of small emboli unlikely to cause harm. This study assessed trends in CTPA use and diagnostic yield. We also assessed trends in PE hospitalizations and mortality to indicate PE severity. (2) Methods: Analysis of Western Australian linked administrative data for 2003-2015 including hospitalizations, emergency department (ED) attendances, and CTPA performed at hospitals. Age-sex standardized trends were calculated for CTPA use, PE hospitalizations, and mortality (as a proxy for severity). Logistic regression assessed diagnostic yield of CTPA following unplanned ED presentations. (3) Results: CTPA use increased from 3.3 per 10,000 person-years in 2003 (95% CI 3.0-3.6) to 17.1 per 10,000 person-years (16.5-17.7) in 2015. Diagnostic yield of CTPA increased from 12.7% in 2003 to 17.4% in 2005, declining to 12.2% in 2015 (p = 0.049). PE hospitalizations increased from 3.8 per 10,000 (3.5-4.1) in 2003 to 5.2 per 10,000 (4.8-5.5) in 2015. Mortality remained constant at 0.50 per 10,000 (0.39-0.62) in 2003 and 0.42 per 10,000 (0.32-0.51) in 2015. (4) Conclusions: CTPA increased from 2003 to 2015, while diagnostic yield decreased, potentially indicating overtesting. PE mortality remained constant despite increasing hospitalizations, likely indicating a higher proportion of less severe cases. As treatment can be harmful, this could represent overdiagnosis.

Unplanned 30-day readmissions, comorbidity and impact on one-year mortality following incident heart failure hospitalisation in Western Australia, 2001-2015

BACKGROUND

Readmissions within 30 days after heart failure (HF) hospitalisation is considered an important healthcare quality metric, but their impact on medium-term mortality is unclear within an Australian setting. We determined the frequency, risk predictors and relative mortality risk of 30-day unplanned readmission in patients following an incident HF hospitalisation.

METHODS

From the Western Australian Hospitalisation Morbidity Data Collection we identified patients aged 25-94 years with an incident (first-ever) HF hospitalisation as a principal diagnosis between 2001 and 2015, and who survived to 30-days post discharge. Unplanned 30-day readmissions were categorised by principal diagnosis. Logistic and Cox regression analysis determined the independent predictors of unplanned readmissions in 30-day survivors and the multivariable-adjusted hazard ratio (HR) of readmission on mortality within the subsequent year.

RESULTS

The cohort comprised 18,241 patients, mean age 74.3 ± 13.6 (SD) years, 53.5% males, and one-third had a modified Charlson Comorbidity Index score of ≥ 3. Among 30-day survivors, 15.5% experienced one or more unplanned 30-day readmission, of which 53.9% were due to cardiovascular causes; predominantly HF (31.4%). The unadjusted 1-year mortality was 15.9%, and the adjusted mortality HR in patients with 1 and ≥ 2 cardiovascular or non-cardiovascular readmissions (versus none) was 1.96 (95% confidence interval (CI) 1.80-2.14) and 3.04 (95% CI, 2.51-3.68) respectively. Coexistent comorbidities, including ischaemic heart disease/myocardial infarction, peripheral arterial disease, pneumonia, chronic kidney disease, and anaemia, were independent predictors of both 30-day unplanned readmission and 1-year mortality.

CONCLUSION

Unplanned 30-day readmissions and medium-term mortality remain high among patients who survived to 30 days after incident HF hospitalisation. Any cardiovascular or non-cardiovascular readmission was associated with a two to three-fold higher adjusted HR for death over the following year, and various coexistent comorbidities were important associates of readmission and mortality risk. Our findings support the need to optimize multidisciplinary HF and multimorbidity management to potentially reduce repeat hospitalisation and improve survival.

Early mortality among aboriginal and non-aboriginal women who had a preterm birth in Western Australia: A population-based cohort study

BACKGROUND

Having a preterm (<37 weeks' gestation) birth may increase a woman's risk of early mortality. Aboriginal and Torres Strait Islander (hereafter Aboriginal) women have higher preterm birth and mortality rates compared with other Australian women.

OBJECTIVES

We investigated whether a history of having a preterm birth was associated with early mortality in women and whether these associations differed by Aboriginal status.

METHODS

This retrospective cohort study used population-based perinatal records of women who had a singleton birth between 1980 and 2015 in Western Australia linked to Death Registry data until June 2018. The primary and secondary outcomes were all-cause and cause-specific mortality respectively. After stratification by Aboriginal status, rate differences were calculated, and Cox proportional hazard regression was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for all-cause and cause-specific mortality.

RESULTS

There were 20,244 Aboriginal mothers (1349 deaths) and 457,357 non-Aboriginal mothers (7646 deaths) with 8.6 million person-years of follow-up. The all-cause mortality rates for Aboriginal mothers who had preterm births and term births were 529.5 and 344.0 (rate difference 185.5, 95% CI 135.5, 238.5) per 100,000 person-years respectively. Among non-Aboriginal mothers, the corresponding figures were 125.5 and 88.6 (rate difference 37.0, 95% CI 29.4, 44.9) per 100,000 person-years. The HR for all-cause mortality for Aboriginal and non-Aboriginal mothers associated with preterm birth were 1.48 (95% CI 1.32, 1.66) and 1.35 (95% CI 1.26, 1.44), respectively, compared with term birth. Compared with mothers who had term births, mothers of preterm births had higher relative risks of mortality from diabetes, cardiovascular, digestive and external causes.

CONCLUSIONS

Both Aboriginal and non-Aboriginal women who had a preterm birth had a moderately increased risk of mortality up to 38 years after the birth, reinforcing the importance of primary prevention and ongoing screening.

The influence of acculturation on the risk of preterm birth and low birthweight in migrant women residing in Western Australia

BACKGROUND

The risk of preterm birth (PTB) and low birthweight (LBW) may change over time the longer that immigrants reside in their adopted countries. We aimed to study the influence of acculturation on the risk of these outcomes in Australia.

METHODS

A retrospective cohort study using linked health data for all non-Indigenous births from 2005-2013 in Western Australia was undertaken. Acculturation was assessed through age on arrival, length of residence, interpreter use and having an Australian-born partner. Adjusted odds ratios (aOR) for term-LBW and PTB (all, spontaneous, medically-indicated) were calculated using multivariable logistic regression in migrants from six ethnicities (white, Asian, Indian, African, Māori, and 'other') for different levels of acculturation, compared to the Australian-born population as the reference.

RESULTS

The least acculturated migrant women, those from non-white non-Māori ethnic backgrounds who immigrated at age ≥18 years, had an overseas-born partner, lived in Australia for < 5 years and used a paid interpreter, had 58% (aOR 1.58, 95% CI 1.15-2.18) higher the risk of term-LBW and 40% (aOR 0.60, 95% CI 0.45-0.80) lower risk of spontaneous PTB compared to the Australian-born women. The most acculturated migrant women, those from non-white non-Māori ethnic backgrounds who immigrated at age <18 years, had an Australian-born partner, lived in Australia for > 10 years and did not use an interpreter, had similar risk of term-LBW but 43% (aOR 1.43, 95% CI 1.14-1.78) higher risk of spontaneous PTB than the Australian-born women.

CONCLUSION

Acculturation is an important factor to consider when providing antenatal care to prevent PTB and LBW in migrants. Acculturation may reduce the risk of term-LBW but, conversely, may increase the risk of spontaneous PTB in migrant women residing in Western Australia. However, the effect may vary by ethnicity and warrants further investigation to fully understand the processes involved.

Ambient air pollution and risk of incident dementia in older men living in a region with relatively low concentrations of pollutants: The Health in Men Study

BACKGROUND

In areas with moderate to severe air pollution, pollutant concentrations are associated with dementia risk. It is unclear whether the same relationship is present in regions with lower ambient air pollution.

OBJECTIVE

To determine whether exposure to air pollution is associated with risk of incident dementia in general, and Alzheimer's disease and vascular dementia in particular, in older men living in a relatively low ambient air pollution region.

METHODS

The cohort comprised 11,243 men residing in Perth, Australia. Participants were aged ≥65 years and free of a dementia diagnosis at time of recruitment in 1996-1999. Incident dementia was identified from recruitment to 2018 via ICD diagnosis codes and subsequent study waves. Concentrations for three air pollutants, nitrogen dioxide (NO₂), fine particulate matter less than 2.5 μm in diameter (PM_2.5), and black carbon (BC) were estimated at participants' home addresses using land-use regression models. We used Cox proportional hazards regression models adjusting for smoking status, physical activity, BMI, education, and socio-economic status.

RESULTS

Of 3053 (27.2%) incident cases of dementia, 1670 (54.7%) and 355 (11.6%) had documented Alzheimer's disease and vascular dementia. The average concentration of NO₂ was 13.5 (SD 4.4) μg/m³, of PM_2.5 was 4.54 (SD 1.6) μg/m³ and of BC was 0.97 (SD 0.29) ×10^-5 m^-1. None of the air pollutants were associated with incident dementia or Alzheimer's disease. In the unadjusted model, increased exposure to PM_2.5 was associated with an increased risk of vascular dementia (for a 5 μg/m³ increase: HR 1.62, 95% CI 1.13, 2.31). However, this association was attenuated following adjustment for confounders (HR 1.39, 95% CI 0.93, 2.08). NO₂ and BC were not associated with vascular dementia incidence.

DISCUSSION

Exposure to air pollution is not associated with increased risk of incident dementia in older men living in a region with relatively low ambient air pollution.

The relationship between thyroid dysfunction, cardiovascular morbidity and mortality in type 2 diabetes: The Fremantle Diabetes Study Phase II

AIMS

It is uncertain whether subclinical thyroid dysfunction is associated with cardiovascular disease (CVD) events and mortality in people with type 2 diabetes. The aim of this study was to determine whether undetected thyroid disease increases the risk of incident CVD and death in type 2 diabetes.

METHODS

One thousand two hundred fifty participants with type 2 diabetes (mean age 65.3 years, 56.5% males, median diabetes duration 8.0 years) without known thyroid disease and not taking medications known to affect thyroid function were categorised, based on baseline serum free thyroxine (FT4) and thyrotropin (TSH) concentrations, as euthyroid, overt hypothyroid (increased TSH, low FT4), subclinical hypothyroid (increased TSH, normal FT4), overt thyrotoxic (decreased TSH, raised FT4) or subclinical thyrotoxic (decreased TSH, normal FT4). Incident myocardial infarction, incident stroke, all-cause and cardiovascular mortality were ascertained during a mean 6.2-6.7 years of follow-up.

RESULTS

Most participants with newly-detected thyroid dysfunction had subclinical hypothyroidism (77.2%) while overt/subclinical thyrotoxicosis was infrequent. Compared to participants with TSH 0.34-2.9 mU/L, those with TSH > 5.1 mU/L were not at increased risk of incident myocardial infarction (adjusted hazard ratio (95% confidence limits) 1.77 (0.71, 2.87)), incident stroke (1.66 (0.58, 4.78)), all-cause mortality (0.78 (0.44, 1.37)) or cardiovascular mortality (1.16 (0.38, 3.58)). Independent baseline associates of subclinical hypothyroidism included estimated glomerular filtration rate and systolic blood pressure.

CONCLUSIONS

Subclinical hypothyroidism was not independently associated with CVD events or mortality in community-dwelling people with type 2 diabetes despite its associations with CVD risk factors, questioning strategies to identify and/or treat mild thyroid dysfunction outside usual care.

Bias in the association between advanced maternal age and stillbirth using left truncated data

Restriction to analysis of births that survive past a specified gestational age (typically 20 weeks gestation) leads to biased exposure-outcome associations. This bias occurs when the cause of restriction (early pregnancy loss) is influenced by both the exposure and unmeasured factors that also affect the outcome. The aim of this study is to estimate the magnitude of bias resulting from left truncated data in the association between advanced maternal age and stillbirth. We simulated data for the causal pathway under a collider-stratification mechanism. Simulation parameters were based on an observed birth cohort from Western Australia and a range of plausible values for the prevalence of early pregnancy loss, unmeasured factor U and the odds ratios for the selection effects. Selection effects included the effects of maternal age on early pregnancy loss, U on early pregnancy loss, and U on stillbirth. We compared the simulation scenarios to the observed birth cohort that was truncated to pregnancies that survived beyond 20 gestational weeks. We found evidence of marginal downward bias, which was most prominent for women aged 40 + years. Overall, we conclude that the magnitude of bias due to left truncation is minimal in the association between advanced maternal age and stillbirth.

Development of prognostic model for preterm birth using machine learning in a population-based cohort of Western Australia births between 1980 and 2015

Preterm birth is a global public health problem with a significant burden on the individuals affected. The study aimed to extend current research on preterm birth prognostic model development by developing and internally validating models using machine learning classification algorithms and population-based routinely collected data in Western Australia. The longitudinal retrospective cohort study involved all births in Western Australia between 1980 and 2015, and the analytic sample contains 81,974 (8.6%) preterm births (< 37 weeks of gestation). Prediction models for preterm birth were developed using regularised logistic regression, decision trees, Random Forests, extreme gradient boosting, and multi-layer perceptron (MLP). Predictors included maternal socio-demographics and medical conditions, current and past pregnancy complications, and family history. Class weight was applied to handle imbalanced outcomes and stratified tenfold cross-validation was used to reduce overfitting. Close to half of the preterm births (49.1% at 5% FPR, 95% CI 48.9%,49.5%) were correctly classified by the best performing classifier (MLP) for all women when current pregnancy information was available. The sensitivity was boosted to 52.7% (95% CI 52.1%,53.3%) after including past obstetric history in a sub-population of births from multiparous women. Around half of the preterm birth can be identified antenatally at high specificity using population-based routinely collected maternal and pregnancy data. The performance of the prediction models depends on the available predictor pool that is individual and time specific.

Neonatal outcomes associated with in utero exposure to oxycodone, overall and by trimester of exposure: A retrospective cohort study

Oxycodone is commonly used by pregnant women for the treatment of pain. However, the potential risk associated with its use in pregnancy have not been robustly evaluated. The objective of this study was to examine neonatal outcomes associated with prenatal oxycodone exposure. State dispensing records were matched with midwives records to identify women who had been dispensed oxycodone during pregnancy (n=302). A matched comparison group of women who had been prescribed oxycodone prior to pregnancy was also identified (n=604). Hospital, mortality and congenital abnormality data were obtained for each mother-child dyad. Neonatal outcomes were examined for association with any exposure during pregnancy and trimester specific exposure, using generalized linear models. First trimester exposure was not associated with a significant increased risk of congenital anomalies (OR: 1.74 95%CI: 0.78, 3.87). Second trimester exposure to oxycodone was associated with reduction in average length of gestation (aCoef:-0.83, 95%CI: -1.26, -0.41) and birth weight (aCoef:-188, 95%CI: -299, -76). Second trimester exposure was also associated with an increased risk of very preterm birth (<32 weeks) (OR: 5.03, 95%CI: 1.95, 12.98) and admission to the special care nursery (aOR:1.99, 95%CI: 1.30, 3.03). Third trimester exposure to oxycodone was associated with a reduction in average length of gestation (aCoef:-0.33, 95%CI: -0.63, -0.02) compared with the comparison group. The use of oxycodone in pregnancy was not associated with an increased risk of congenital anomalies. However, oxycodone exposure was associated with a short period of gestation, preterm birth, and NAS, which likely contributed to a longer period of hospitalization following birth. PERSPECTIVE: This article assesses the neonatal risks associated with prenatal exposure to oxycodone, providing clinicians and patients with important information on the safety of oxycodone in the treatment of pain in pregnancy.

Opioid poisoning during pregnancy: prevalence, characteristics, and neonatal outcomes

While it has been postulated that opioid poisoning during pregnancy may cause adverse maternal and neonatal outcomes, the harm associated with opioid poisoning during pregnancy has not been robustly examined. Pregnant women admitted to hospital or presenting to the emergency department (ED) in Western Australia (WA) with a diagnosis of opioid poisoning were identified by linking state midwifery records with hospital and ED administrative data. Maternal and neonatal outcomes were compared with opioid poisoning that occurred in the 12 months prior to conception or the 12 months following birth. Between 2003 and 2018, 57 neonates were born to women who had experienced opioid poisoning during pregnancy (14.1 per 100,000 births) in WA. The incidence of opioid poisoning in the year prior to pregnancy (IRR: 3.04, 95%CI: 2.30, 4.02) and the year following pregnancy (IRR: 1.96, 95%CI: 1.46, 2.64) was significantly higher than during pregnancy. Opioid poisoning during pregnancy was less likely to involve multiple substances and be intentional (rather than accidental). Neonatal conditions associated with in utero hypoxia were significantly less common in neonates born to women who experience opioid poisoning prior to pregnancy compared with during pregnancy (OR: 0.17, 95%CI: 0.04, 0.80). Opioid poisoning in pregnancy was not associated with an increased risk of other serious adverse neonatal outcomes. Opioid poisoning during pregnancy is uncommon and less likely to be intentional and involve multiple substances. Opioid poisoning during pregnancy is likely associated with an increased risk of conditions associated with in utero hypoxia.

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.