Cross-sectional, case-control and longitudinal associations between exposure to glucagon-like peptide-1 receptor agonists and the dispensing of antidepressants

AIM

To determine if the dispensing of glucagon-like peptide (GLP)-1 receptor agonists is associated with increased dispensing of antidepressants.

MATERIALS AND METHODS

We used cross-sectional, case-control and retrospective cohort study designs to examine the association between dispensed GLP-1 receptor agonists and antidepressants between 2012 and 2022 in the 10% random sample of the Australian Pharmaceutical Benefits Scheme (PBS) data. PBS-listed GLP-1 receptor agonists, exenatide, dulaglutide and semaglutide were the exposures. Outcomes were the odds ratio [ORs; 99% confidence interval (CI)] and hazard ratio (99% CI) of being dispensed any antidepressant. Analyses were adjusted for demographic measures and the dispensing of medicines to manage cardiovascular diseases or anxiety/insomnia. Statistical tests were two-sided at the 1% level of significance.

RESULTS

In total, 358 075 of 1 746 391 individuals were dispensed antidepressants, and 8495 of the 24 783 dispensed a GLP-1 receptor agonist were also dispensed an antidepressant in 2022 (OR 1.44; 99% CI 1.38-1.50); 24 103 of the 1 746 391 participants had been dispensed a GLP-1 receptor agonist between 2012 and 2021, and of these 8083 were dispensed antidepressants in 2022 (OR 1.52; 99% CI 1.46-1.59). The 2012 cohort included 1 213 316 individuals who had not been dispensed antidepressants that year. The hazard ratio of being dispensed an antidepressant between 2013 and 2022 following the dispensing of a GLP-1 receptor agonist was 1.19 (99% CI 1.12-1.27). Additional analyses restricting the time of exposure confirmed these associations for all PBS-listed GLP-1 receptor agonists.

CONCLUSIONS

Individuals exposed to GLP-1 receptor agonists are at greater risk of being dispensed antidepressants. The possible impact of GLP-1 receptor agonists on the mood of consumers requires ongoing vigilance and further research.

Observational evidence linking psychotropic medicines to the dispensing of opioid agents in later life

BACKGROUND

The use of opioid medicines is common in developed countries, particularly among older adults and those with mental health disorders. It is unclear if the association between mental disorders and opioid medicines is causal, or is due to reverse causality or confounding.

METHODS

We used a 10% random sample of the Australian Pharmaceutical Benefits Scheme (years 2012-2022) to examine the cross-sectional, case-control and longitudinal association between the dispensing of antidepressants, anxiolytics, hypnotics, antipsychotics and lithium, and opioid medicines. We used logistic regression, structural equation models (SEM), and Cox regression to analyze the data. Analyses were adjusted for age (years), sex, and number of non-psychotropic medicines dispensed during the year.

RESULTS

The 2022 file contained 804 334 individuals aged 50 years or over (53.1% women), of whom 181 690 (22.6%) received an opioid medicine. The adjusted odds ratio of being dispensed opioid medicines was 1.44 (99% CI = 1.42-1.46) for antidepressants, 1.97 (99% CI = 1.92-2.03) for anxiolytics, 1.55 (99% CI = 1.51-1.60) for hypnotics, 1.32 (99% CI = 1.27-1.38) for antipsychotics, and 0.60 (99% CI = 0.53-0.69) for lithium. Similar associations were noticed when we compared participants who were or not dispensed opioid medicines in 2022 for exposure to psychotropic agents between 2012 and 2021. SEM confirmed that this association was not due to reverse causality. The dispensing of antidepressants was associated with increased adjusted hazard (HR) of subsequent dispensing of opioid medicines (HR = 1.29, 99% CI = 1.27-1.30). Similar associations were observed for anxiolytics, hypnotics and antipsychotics, but not lithium.

CONCLUSIONS

The dispensing of opioid medicines is higher among older individuals exposed to antidepressants, anxiolytics, hypnotics and antipsychotics than those who are not. These associations are not due to reverse causality or study design. Preventive strategies seeking to minimise the risk of inappropriate use of opioid medicines in later life should consider targeting this high-risk population.

Analysis and evaluation of explainable artificial intelligence on suicide risk assessment

This study explores the effectiveness of Explainable Artificial Intelligence (XAI) for predicting suicide risk from medical tabular data. Given the common challenge of limited datasets in health-related Machine Learning (ML) applications, we use data augmentation in tandem with ML to enhance the identification of individuals at high risk of suicide. We use SHapley Additive exPlanations (SHAP) for XAI and traditional correlation analysis to rank feature importance, pinpointing primary factors influencing suicide risk and preventive measures. Experimental results show the Random Forest (RF) model is excelling in accuracy, F1 score, and AUC (>97% across metrics). According to SHAP, anger issues, depression, and social isolation emerge as top predictors of suicide risk, while individuals with high incomes, esteemed professions, and higher education present the lowest risk. Our findings underscore the effectiveness of ML and XAI in suicide risk assessment, offering valuable insights for psychiatrists and facilitating informed clinical decisions.

Prospective Association Between the Dispensing of Antidepressants and of Medications to Treat Osteoporosis in Older Age

BACKGROUND

Osteoporosis is a common condition associated with fragility fractures, especially in older individuals and women. Antidepressants have emerged as a potential risk factor, but their association with bone fragility remains uncertain because the results of past studies are difficult to generalize. We aimed to investigate the association between antidepressant exposure and subsequent treatment for osteoporosis in a nationally representative sample of Australians.

METHODS

Cohort study using a 10% random sample of the Pharmaceutical Benefits Scheme (PBS) data for 2012, that included 566,707 individuals aged older than or equal to 50 years not dispensed osteoporosis medications. The effect of exposure to antidepressants during 2012 (prevalent or incident) or later (up to 2022) was examined using Cox regression models adjusted for age, sex, comorbidities and other psychotropic medications.

RESULTS

Over 10 years, 73,360 (12.94%) received osteoporosis medications; 16,216 (22.10%) had been dispensed antidepressants in 2012. The hazard of osteoporosis medication dispensing was higher among those exposed to antidepressants (HR = 1.16, 99% CI = 1.14-1.18; average duration of follow up: 8.0 ± 3.1 years, range: 1-10 years). The hazard of osteoporosis medication diminished with increasing age, and the effect of antidepressants was 37%-76% more pronounced among men in the 50s and 60s. Different classes of antidepressants had a similar risk profile.

CONCLUSION

The dispensing of antidepressants in older age is associated with higher hazard of subsequent dispensing of medications for osteoporosis, and this association is more marked for young older adults, particularly men. Clinicians should monitor the bone health of older individuals treated with antidepressants in order to decrease the morbidity associated with fragility fractures.

Adherence to pharmacotherapy: sine qua non for reducing cumulative risk of premature coronary disease in familial hypercholesterolemia

PURPOSE OF REVIEW

Familial hypercholesterolemia (FH) is a dominant and highly penetrant monogenic disorder present from birth that markedly elevates plasma low-density lipoprotein (LDL)-cholesterol concentration and, if untreated, leads to atherosclerotic cardiovascular disease (ASCVD). The risk of ASCVD can be substantially reduced with lipid-lowering treatment (LLT). However, adherence to LLT remains a major challenge in FH patients and an under-recognized issue. We review several barriers to treatment adherence and implementation strategies for improving adherence in patients with FH.

RECENT FINDINGS

Barriers that negatively affect patient adherence to treatment include the misunderstanding of perceived and actual risk of FH and the benefits of LLT, inadequate knowledge, lack of standardization of treatment, insufficient monitoring of LDL-cholesterol level, and inequalities in healthcare resources. Education of patients, carers and healthcare providers, guideline-directed treatment goals, regular monitoring, medication regimen simplification and greater access to established and new drugs are crucial enablers for improving adherence to treatment. However, given FH is present from birth, strategies for life-long adherence from childhood or young adulthood is critically important and requires further study. To be effective, strategies should be multifaceted, targeted and patient-centred involving a multidisciplinary-team with support from family, communities and peer groups.

SUMMARY

FH confers a significant risk for ASCVD from a young age. Achieving better medication adherence is foundational for improving clinical outcomes and reducing the burden of atherosclerosis over a lifetime. Identification of key barriers and enablers are critical for implementing better adherence to treatment across the life-course of patients with FH.

Contemporary trends in anaphylaxis burden and healthcare utilisation in Western Australia: A linked data study

Background

Anaphylaxis is a growing public health problem in Australia. To determine the extent of the problem, we linked multiple health datasets to examine temporal trends in anaphylaxis events across the health system in Western Australia (WA).

Methods

We identified an anaphylaxis cohort from 1980 to 2020 using linked datasets from ambulance, emergency departments, hospital inpatients and deaths. Age-standardised anaphylaxis event rates were calculated from 2010 to 2020. Dataset-specific rates for anaphylaxis were also examined, to show differences in health care utilisation. Annual percent change in rates (2010-2019) were estimated using age-adjusted Poisson regression models.

Results

A total of 19 140 individuals (mean age 31 years; 51% female) experienced 24 239 anaphylaxis events between 2010 and 2020. From 2010 to 2019, the average annual percent increase (95% CI) in rates was 5.3% (4.8-5.8%), from 70.3 to 113.9, with rates reducing to 76.5/100 000 population in 2020. Adolescents and young adults aged 5-14 years and 15-24 years had the greatest increase of 6.9% (5.6-8.1%) and 6.8% (5.6-8.0) respectively, with those over 25 years increasing by approximately 5% per year and children 1-4 years showing the lowest annual increase of 2.6% (1.1-4.2%). The highest absolute rates were seen in under 1 year (269.7/100 000; 2019). There has been an acceleration of trends from 2015 to 2019, underpinned by large increases in 15-24 and 25-34 years. All databases, show similar increasing trends, with ambulance attendance (33.7 per 100 000), emergency presentation (89.8 per 100 000) and hospital admissions (46.2 per 100 000), for anaphylaxis highest in 2019. However, whilst ambulance and emergency presentations have grown by 8.9% (95%CI 7.9-9.8%) and 6.6% per year (95%CI 6.0-7.2%), respectively, hospitalisations appear to be steadying with only a 0.9% (95%CI 0.2-1.6%) yearly rise.

Conclusion

Rates of anaphylaxis continue to increase, with WA having higher rates than previous estimates for Australia. Whilst rates are still high in infants, lower trends in children compared to older ages may indicate better prevention of allergy. Results show more people experiencing anaphylaxis now receive care in emergency and ambulance, rather than hospital. Further exploration of the patient care journey through prehospital and inpatient care is required, to understand the changing health demands of people who experience anaphylaxis.

Clinical outcomes and health care costs of transferring rural Western Australians for invasive coronary angiography, and a cost-effective alternative care model: a retrospective cross-sectional study

OBJECTIVES

To examine the severity of coronary artery disease (CAD) in people from rural or remote Western Australia referred for invasive coronary angiography (ICA) in Perth and their subsequent management; to estimate the cost savings were computed tomography coronary angiography (CTCA) offered in rural centres as a first line investigation for people with suspected CAD.

DESIGN

Retrospective cohort study.

SETTING, PARTICIPANTS

Adults with stable symptoms in rural and remote WA referred to Perth public tertiary hospitals for ICA evaluation during the 2019 calendar year.

MAIN OUTCOME MEASURES

Severity and management of CAD (medical management or revascularisation); health care costs by care model (standard care or a proposed alternative model with local CTCA assessment).

RESULTS

The mean age of the 1017 people from rural and remote WA who underwent ICA in Perth was 62 years (standard deviation, 13 years); 680 were men (66.9%), 245 were Indigenous people (24.1%). Indications for referral were non-ST elevation myocardial infarction (438, 43.1%), chest pain with normal troponin level (394, 38.7%), and other (185, 18.2%). After ICA assessment, 619 people were medically managed (60.9%) and 398 underwent revascularisation (39.1%). None of the 365 patients (35.9%) without obstructed coronaries (< 50% stenosis) underwent revascularisation; nine patients with moderate CAD (50-69% stenosis; 7%) and 389 with severe CAD (≥ 70% stenosis or occluded vessel; 75.5%) underwent revascularisation. Were CTCA used locally to determine the need for referral, 527 referrals could have been averted (53%), the ICA:revascularisation ratio would have improved from 2.6 to 1.6, and 1757 metropolitan hospital bed-days (43% reduction) and $7.3 million in health care costs (36% reduction) would have been saved.

CONCLUSION

Many rural and remote Western Australians transferred for ICA in Perth have non-obstructive CAD and are medically managed. Providing CTCA as a first line investigation in rural centres could avert half of these transfers and be a cost-effective strategy for risk stratification of people with suspected CAD.

Risk of early recurrence and mortality in high-risk myocardial infarction patients: A population-based linked data study

Background

Survival during the early period following myocardial infarction (MI) has significantly improved although there are limited data on cardiovascular recurrence during this period.

Methods

We identified all emergency hospitalisations for MI from November 1, 2011 to October 31, 2016 in Western Australia from a linked hospitalisation/mortality dataset. Patients were included if they survived >3 days, had no acute kidney injury, and had ≥1 of: ≥65 years, prior MI, diabetes or peripheral arterial disease. Outcomes were major adverse cardiovascular events (MACE, a composite of CVD death, recurrent MI or stroke), cardiovascular disease (CVD) death, all-cause mortality, recurrent MI and stroke. Cumulative risks at 90-days and 1-year were estimated from Kaplan-Meier analyses and predictors of each outcome from multivariable Cox regression models.

Results

There were 8024 high-risk MI patients identified (males 61.8%). Median age was 73.7 years (IQR 66.3-82.2). Half of the risk of MACE occurred in the first 90-days post-MI (6.6% vs 12.6% at 1-year) and was underpinned by risk of recurrent MI. Risk was generally higher in women than men (MACE: 6.0% males, 7.7% females, p = 0.0025; CVD mortality: 1.7% males, 3.7% females; all-cause mortality: 2.8% males, 5.6% females, p < 0.0001). Independent predictors of 90-day MACE were increasing age, heart failure history, hypertension and prior stroke. Female sex was not associated with a higher rate of any of the outcomes after multivariable adjustment.

Conclusion

Half of cardiovascular events in the year following an MI occur within 90-days, demonstrating that reductions in MI burden could be achieved by further targeted intervention in the early period following an MI.

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.

Antihypertensive Medication Adherence and the Risk of Vascular Events and Falls After Stroke: A Real-World Effectiveness Study Using Linked Registry Data

BACKGROUND

Real-world evidence is limited on whether antihypertensive medications help avert major adverse cardiovascular events (MACE) after stroke without increasing the risk of falls. We investigated the association of adherence to antihypertensive medications on the incidence of MACE and falls requiring hospitalization after stroke.

METHODS

A retrospective cohort study of adults who were newly dispensed antihypertensive medications after an acute stroke (Australian Stroke Clinical Registry 2012-2016; Queensland and Victoria). Pharmaceutical dispensing records were used to determine medication adherence according to the proportion of days covered in the first 6 months poststroke. Outcomes between 6 and 18 months postdischarge included: (i) MACE, a composite outcome of all-cause death, recurrent stroke or acute coronary syndrome; and (ii) falls requiring hospitalization. Estimates were derived using Cox models, adjusted for >30 confounders using inverse probability treatment weights.

RESULTS

Among 4076 eligible participants (median age 68 years; 37% women), 55% had a proportion of days covered ≥80% within 6 months postdischarge. In the subsequent 12 months, 360 (9%) participants experienced a MACE and 337 (8%) experienced a fall requiring hospitalization. After achieving balance between groups, participants with a proportion of days covered ≥80% had a reduced risk of MACE (hazard ratio: 0.68; 95% CI: 0.54-0.84) and falls requiring hospitalization (subdistribution hazard ratio: 0.78; 95% CI: 0.62-0.98) than those with a proportion of days covered <80%.

CONCLUSIONS

High adherence to antihypertensive medications within 6 months poststroke was associated with reduced risks of both MACE and falls requiring hospitalization. Patients should be encouraged to adhere to their antihypertensive medications to maximize poststroke outcomes.

Overview of registries for anaphylaxis: a scoping review

OBJECTIVE

This review aimed to describe the scope and operational features of anaphylaxis registries, and to assess their contribution to improving knowledge of anaphylaxis and care of patients who experience anaphylaxis by measuring their research output.

INTRODUCTION

Structured data collection and reporting systems, such as registries, are needed to better understand the burden of anaphylaxis and to protect the growing number of patients with severe allergy. There is a need to characterize current anaphylaxis registries to identify their value in anaphylaxis surveillance, management, and research. Information synthesized in this review will provide knowledge on benefits and gaps in current registries, which may inform the implementation and global standardization of future anaphylaxis reporting systems.

INCLUSION CRITERIA

This scoping review considered literature describing registries worldwide that enroll patients who have experienced anaphylaxis. Published and gray literature sources were included if they described the scope and operational features of anaphylaxis registries.

METHODS

This review followed the JBI methodology for scoping reviews. Embase, MEDLINE, Scopus, and CINAHL were searched for relevant articles. Identified keywords and index terms were adapted for searches of gray literature sources, using Google advanced search functions. Only full-text studies in English were considered for inclusion. Two independent reviewers conducted title and abstract screening and those that did not meet the inclusion criteria were excluded. The full text of potentially relevant articles were retrieved; full-text screening and data extraction were also conducted by two independent reviewers. Any discrepancies were resolved through discussion or with a third reviewer. Tables and a narrative summary were used to describe and compare the scope and features (eg, inclusion criteria, patient demographics, clinical symptoms) of the identified anaphylaxis registries, and to outline their output to assess their contribution to research and clinical practice for anaphylaxis.

RESULTS

A total of 77 full-text publications and eight gray literature sources were used to extract data. The literature search identified 19 anaphylaxis registries, with sites in 28 countries including Europe, the United Kingdom, Canada, the United States, Korea, and Australia. The main purposes of the identified registries were to collect clinical data for research; provide clinical support tools to improve patient care; and operate as allergen surveillance systems to protect the wider community with allergies. Differences in inclusion and health care settings exist, with 11 collecting data on anaphylaxis of any cause, two on food reactions alone, three on fatal anaphylaxis, one on perioperative anaphylaxis, and two on allergic reactions (including anaphylaxis). Five registries enroll cases in allergy centers, five in hospital settings, one in schools, and others target a combination of general practitioners, specialists in emergency departments, and other relevant hospital departments and allergy outpatient clinics. Only three registries operate under a mandatory framework. A total of 57 publications were considered research outputs from registries. All registries except two have published studies from collected data, with the greatest number of articles published from 2019 to the present. Publications mostly addressed questions regarding demographic profile, causes and cofactors, severity, fatal reactions, and gaps in management.

CONCLUSIONS

This review demonstrated that anaphylaxis registries differ in their scope and operation, having been established for different purposes. Importantly, registries have contributed significantly to research, which has highlighted gaps in anaphylaxis management, provoking allergens, and informed targets for prevention for severe and fatal events. Beyond this, registries relay information about anaphylaxis to clinicians and regulatory bodies to improve patient care and protect the community. The ability to link registry data with other health datasets, standardization of data across registries, and incorporation of clinical care indicators to promote quality health care across the health system represent important targets for future systems.

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.

Temporal trends in myocardial infarction case fatality: methodological challenges and prevention targets

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Health and Medical Research Council of AustraliaHealy Medical Research Foundation

Background

Case fatality is an important indicator of severity and quality of care for myocardial infarction (MI). Most studies focus on hospitalised case fatality, which does not capture the total burden of MI deaths. Additionally, changes in diagnostic criteria and acute clinical care, and evidence that identifying all coronary heart disease (CHD) events better captures this patient group,1 have led to suggestions that a different definition of case fatality is required.

Purpose

The aim of the study was to determine the impact of different definitions of case fatality on the composition of fatal cases, and to measure trends in case fatality across a range of case definitions.

Methods

A whole-state linked hospital/death dataset was used to identify all MI, acute coronary syndromes (ACS) and CHD events (fatal + nonfatal) from 1997-2015. The traditional MI case fatality definition included all MI deaths as the numerator, stratified as MI hospitalisation with death ≤28 days, non-MI hospitalisation with MI death ≤28 days, or pre-hospital MI deaths. The denominator was all MIs (fatal plus nonfatal MI). ACS and a broader CHD definition were trialled, with ACS or CHD deaths as the numerator respectively, stratified in a similar manner as MI. Case fatality was age-standardised by 5-year age group using the internal age distribution of each definition as the standard.

Results

From 1997 to 2015, there were 76,928 MI events, 126,470 ACS events, and 235,100 CHD events. Of the MI cohort, 64.1% were men, and 13.0% had a prior MI, with a similar pattern in the ACS and CHD cohorts. For the traditional definition of MI case fatality, 10,819 deaths (53.9%) occurred pre-hospital, 4990 deaths in those hospitalised for MI and dying ≤28 days (24.8%), and 4271 MI deaths (21.3%) ≤28 days of a non-MI hospitalisation (Figure). Using the broadest CHD definition of case fatality, there was a similar proportion of pre-hospital deaths, but a higher proportion of CHD deaths in those with a non-CHD hospitalisation.

In men, age-standardised MI case fatality declined from 40.0% in 1997 to 17.3% by 2015; in women, the decline was from 41.9% to 18.2%. In contrast, using the ACS and broad CHD definitions, age-standardised case fatality was lower than for MI throughout the study period, with a smaller temporal decline (ACS: men 22.2% to 13.1%, women 20.5% to 13.0%; CHD: men 20.6% to 12.4%, women 19.3% to 12.3%).

Conclusion

Despite substantial falls in MI case fatality, the fatal burden remains high. Regardless of the case fatality definition, pre-hospital deaths from acute or all CHD have remained high over time, highlighting the need to target the pre-hospital setting. Caution is needed when using different definitions of case fatality to ensure relevant statistics are used, particularly for temporal trends.

Figure Legend. Proportion of MI deaths occurring ≤28 days after MI hospitalisation (2), ≤28 days after non-MI hospitalisation (3), and pre-hospital (4).

Towards better reporting of the Proportion of Days Covered method in cardiovascular medication adherence: A scoping review and new tool TEN-SPIDERS

Although medication adherence is commonly measured in electronic datasets using the proportion of days covered (PDC), no standardized approach is used to calculate and report this measure. We conducted a scoping review to understand the approaches taken to calculate and report the PDC for cardiovascular medicines to develop improved guidance for researchers using this measure. After prespecifying methods in a registered protocol, we searched Ovid Medline, Embase, Scopus, CINAHL Plus and grey literature (1 July 2012 to 14 December 2020) for articles containing the terms “proportion of days covered” and “cardiovascular medicine”, or synonyms and subject headings. Of the 523 articles identified, 316 were reviewed in full and 76 were included (93% observational studies; 47% from the USA; 2 grey literature articles). In 45 articles (59%), the PDC was measured from the first dispensing/claim date. Good adherence was defined as 80% PDC in 61 articles, 56% of which contained a rationale for selecting this threshold. The following parameters, important for deriving the PDC, were often not reported/unclear: switching (53%), early refills (45%), in‐hospital supplies (45%), presupply (28%) and survival (7%). Of the 46 articles where dosing information was unavailable, 59% reported how doses were imputed. To improve the transparent and systematic reporting of the PDC, we propose the TEN‐SPIDERS tool, covering the following PDC parameters: Threshold, Eligibility criteria, Numerator and denominator, Survival, Presupply, In‐hospital supplies, Dosing, Early Refills, and Switching. Use of this tool will standardize reporting of the PDC to facilitate reliable comparisons of medication adherence estimates between studies.

Prior oral proton-pump inhibitor use is associated with reduced severity of aspirin-related upper gastrointestinal bleeding in older people

Low-dose aspirin is commonly used for primary or secondary prophylaxis against cardiovascular disease in older people. However, the potential risk of upper gastrointestinal (UGI) ulceration and bleeding associated with low-dose aspirin use is often not appreciated by prescribers and older consumers. Among 133 serial patients with UGI bleeding, aspirin-users aged ≥70 years had a ninefold increased likelihood of overt UGI bleeding compared with non-users, reducing by 90% in regular proton-pump inhibitor users (adjusted odds ratio 0.10). We recommend risk-versus-benefit discussions when recommending aspirin to older people.

Long-Term Echocardiographic Follow-Up After Transcatheter Aortic Valve Implantation to Assess Structural Valve Deterioration and Bioprosthetic Valve Failure

BACKGROUND

Indications for transcatheter aortic valve implantation (TAVI) in aortic stenosis are expanding and the life expectancy of patients following TAVI is increasing. Determining the long-term durability of TAVI valves is therefore important. Rates of long-term (≥5 years) structural valve deterioration (SVD) vary widely and there are currently no comparable data from Australia. The aim herein was to determine the incidence of haemodynamic SVD and bioprosthetic valve failure (BVF) using recently standardised definitions in a Western Australian cohort after at least 5 years.

METHODS

This is a retrospective cohort study of consecutive patients undergoing TAVI at Royal Perth Hospital between January 2009 and January 2015. Of 211 patients, 55 survived ≥5 years and had echocardiographic data available for review. Median time to the echocardiogram was 5.9 years (max 7.8 years); 49% male, mean age 83 years.

RESULTS

Of the 55 survivors who had echocardiograms available ≥5 years after TAVI, four (9%) had moderate haemodynamic SVD and one (2%) had severe SVD and BVF.

CONCLUSIONS

Our results suggest excellent long-term durability of contemporary TAVI valves in an Australian cohort with very low incidence of SVD and BVF. These findings add confidence to the expanding applications of TAVI valves.

Treatment with Multiple Therapeutic Classes of Medication is Associated with Survival after Stroke

INTRODUCTION

Treatment with several therapeutic classes of medication is recommended for secondary prevention of stroke. We analysed the associations between the number of classes of prevention medications supplied within 90 days post-discharge for ischemic stroke (IS)/transient ischemic attack (TIA) and survival.

PATIENTS AND METHODS

Retrospective cohort study of adults with first-ever IS/TIA (2010-2014) from the Australian Stroke Clinical Registry individually linked with data from national pharmaceutical and Medicare claims. Exposure was the number of classes of recommended medications, i.e. blood pressure-lowering, antithrombotic or lipid-lowering agents, supplied to patients within 90 days post-discharge for IS/TIA. The longitudinal association between the number of classes of medications and survival was evaluated with Cox proportional hazards regression models using the landmark approach. A landmark date of 90 days post-hospital discharge was used to separate exposure and outcome periods and only patients who survived until this date were included.

RESULTS

Of 8,429 patients (43% female, median age 74 years, 80% IS), 607 (7%) died in the year following 90 days post-discharge. Overall, 56% of patients were supplied all three classes of medications, 28% two classes of medications, 11% one class of medications, and 5% no class of medications. Compared to patients supplied all three medication classes, adjusted hazard ratios for all-cause mortality ranged from 1.43 (95% confidence interval [CI]: 1.18-1.72) in those supplied two medication classes to 2.04 (CI: 1.44-2.88) in those supplied with no medication class.

CONCLUSION

Treatment with all three classes of guideline-recommended medications within 90 days post-discharge was associated with better survival. Ongoing efforts are required to ensure optimal pharmacological intervention for secondary prevention of stroke.

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

BACKGROUND AND OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Developing PHarmacie-R: A bedside risk prediction tool with a medicines management focus to identify risk of hospital readmission

BACKGROUND

The imperative to identify patients at risk of medication-related harm has never been greater. Hospital clinicians cannot easily predict risk of readmission or harm. Candidate variables associated with medication-related harm derived from the literature or significantly represented in a complex patient cohort have been previously described by PHarmacie-4. With a focus on polypharmacy and high-risk medicines in vulnerable patient cohorts, PHarmacie-4 was easy to use and highlighted risks. However it over-estimated risk, reducing its usefulness in stratifying risk of readmission.

OBJECTIVE

Develop a risk prediction tool built into a smart phone app, enabling clinicians to identify and refer high-risk patients for an early post-discharge medicines review. Demonstrate usability, real world application and validity in an independent dataset.

METHODS

A retrospective, observational study was conducted with 1201 randomly selected patients admitted to Sir Charles Gairdner Hospital between June 1, 2016 to December 31, 2016. Patient characteristics and outcomes of interest were reported, including unplanned hospital utilisation at 30, 60 and 90 days post-discharge. Using multivariable logistic regression modelling, an algorithm was developed, built into a smart phone app and used and validated in an independent dataset.

RESULTS

738 patients (61%) were included in the derivation sample. The best predictive performance was achieved by PHarmacie-R (C-statistic 0.72, 95% CI 0.68-0.75) which included PHarmacie-4 risk variables, a non-linear effect of age, unplanned hospital utilisation in the preceding six months and gender. The independent validation dataset had a C-statistic of 0.64 (95% CI 0.56-0.72).

CONCLUSION

PHarmacie-R is the first readmission risk prediction tool, built into a smart phone app, focussing on polypharmacy and high-risk medicines in vulnerable patients. It can assist clinical pharmacists to identify medical inpatients who may benefit from early post-discharge medication management services. External validation is needed to enable application in other clinical settings.

Greater Adherence to Secondary Prevention Medications Improves Survival After Stroke or Transient Ischemic Attack: A Linked Registry Study

BACKGROUND AND PURPOSE

Although a target of 80% medication adherence is commonly cited, it is unclear whether greater adherence improves survival after stroke or transient ischemic attack (TIA). We investigated associations between medication adherence during the first year postdischarge, and mortality up to 3 years, to provide evidence-based targets for medication adherence.

METHODS

Retrospective cohort study of 1-year survivors of first-ever stroke or TIA, aged ≥18 years, from the Australian Stroke Clinical Registry (July 2010-June 2014) linked with nationwide prescription refill and mortality data (until August 2017). Adherence to antihypertensive agents, statins, and nonaspirin antithrombotic medications was based on the proportion of days covered from discharge until 1 year. Cox regression with restricted cubic splines was used to investigate nonlinear relationships between medication adherence and all-cause mortality (to 3 years postdischarge). Models were adjusted for age, sex, socioeconomic position, stroke factors, primary care factors, and concomitant medication use.

RESULTS

Among 8363 one-year survivors of first-ever stroke or TIA (44% aged ≥75 years, 44% female, 18% TIA), 75% were supplied antihypertensive agents. In patients without intracerebral hemorrhage (N=7446), 84% were supplied statins, and 65% were supplied nonaspirin antithrombotic medications. Median adherence was ≈90% for each medication group. Between 1% and 100% adherence, greater adherence to statins or antihypertensive agents, but not nonaspirin antithrombotic agents, was associated with improved survival. When restricted to linear regions above 60% adherence, each 10% increase in adherence was associated with a reduction in all-cause mortality of 13% for antihypertensive agents (hazard ratio, 0.87 [95% CI, 0.81-0.95]), 13% for statins (hazard ratio, 0.87 [95% CI, 0.80-0.95]), and 15% for nonaspirin antithrombotic agents (hazard ratio, 0.85 [95% CI, 0.79-0.93]).

CONCLUSIONS

Greater levels of medication adherence after stroke or TIA are associated with improved survival, even among patients with near-perfect adherence. Interventions to improve medication adherence are needed to maximize survival poststroke.

Agreement between pharmaceutical claims data and patient-reported medication use after stroke

OBJECTIVES

To assess the agreement between pharmaceutical claims data and patient-reported medication use after stroke.

METHODS

Claims data from the Pharmaceutical Benefits Scheme were used to estimate medication use for a subset of participants registered in the Australian Stroke Clinical Registry in 2016. Estimates on medication use were validated against patient-reported responses (considered the reference standard).

KEY FINDINGS

For antihypertensive and lipid-lowering medications, the sensitivity of claims data was excellent (85-87%) and the specificity was good (73-78%). Whereas for antithrombotic medications, sensitivity was modest (61%), but specificity was excellent (85%).

CONCLUSIONS

Pharmaceutical claims data can be used to infer medication use after stroke with mostly good to excellent sensitivity and specificity compared with the patient report.

Associations of a Preoperative Anemia and Suboptimal Iron Stores Screening and Management Clinic in Colorectal Surgery With Hospital Cost, Reimbursement, and Length of Stay: A Net Cost Analysis

BACKGROUND

In 2016, a preoperative clinic was implemented to screen, evaluate, and manage anemia and suboptimal iron stores at a major tertiary care medical center in Western Australia. Few studies compare the costs and reimbursements associated with preoperative anemia and suboptimal iron stores management. The objective of our study was to conduct a net cost analysis associated with the implementation of this clinic.

METHODS

We designed a retrospective cohort study involving elective colorectal surgical admissions over a 3-year period. The baseline year selected was the 2015-2016 financial year, with outcomes in the 2016-2017 and 2017-2018 year compared to baseline. The study perspective was the Western Australian Health System. Hospital costs were extracted from the health service clinical costing system, which captures costs at the admission level. The primary outcome was net cost, defined as gross cost minus reimbursement (or funding) received.

RESULTS

Our 3-year study included 544 admissions for elective colorectal surgery. After the implementation of the preoperative clinic, 73.4% (n = 257) of admissions were screened for anemia and suboptimal iron stores, and 31.4% (n = 110) received intravenous iron. In our adjusted analysis, when comparing the final year (2017-2018) with baseline (2015-2016), the units of red blood cells transfused per admission decreased 53% (142 vs 303 units per 1000 discharges; P = .006), and mean hospital length of stay decreased 15% (7.7 vs 9.1 days; P = .008). When comparing the final year with baseline, rectal resection admissions were associated with a mean decrease in the net cost of Australian dollar (A$) 7619 (95% confidence interval, 4230-11,008; P < .001) between 2015-2016 and 2017-2018. For small and large bowel procedures, there was a mean decrease of A$6744 (95% confidence interval, 2430-11,057; P = .002).

CONCLUSIONS

The implementation of a preoperative anemia and suboptimal iron stores screening and management clinic in elective colorectal surgery was associated with reductions in red cell transfusions, length of stay, and net costs.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Invasive Coronary Angiography after Chest Pain Presentations to Emergency Departments

We investigated patients presenting to emergency departments (EDs) with chest pain to identify factors that influence the use of invasive coronary angiography (ICA). Using linked ED, hospitalisations, death and cardiac biomarker data, we identified people aged 20 years and over who presented with chest pain to tertiary public hospital EDs in Western Australia from 1 January 2016 to 31 March 2017 (ED chest pain cohort). We report patient characteristics, ED discharge diagnosis, pathways to ICA, ICA within 90 days, troponin test results, and gender differences. Associations were examined with the Pearson Chi-squared test and multivariate logistic regression. There were 16,974 people in the ED chest pain cohort, with a mean age of 55.6 years and 50.7% males, accounting for 20,131 ED presentations. Acute coronary syndrome was the ED discharge diagnosis in 10.4% of presentations. ED pathways were: discharged home (57.5%); hospitalisation (41.7%); interhospital transfer (0.4%); and died in ED (0.03%)/inpatients (0.3%). There were 1546 (9.1%) ICAs performed within 90 days of the first ED chest pain visit, of which 59 visits (3.8%) had no troponin tests and 565 visits (36.6%) had normal troponin. ICAs were performed in more men than women (12.3% vs. 6.1%, p < 0.0001; adjusted OR 1.89, 95% CI 1.65, 2.18), and mostly within 7 days. Equal numbers of males and females present with chest pain to tertiary hospital EDs, but men are twice as likely to get ICA. Over one-third of ICAs occur in those with normal troponin levels, indicating that further investigation is required to determine risk profile, outcomes and cost effectiveness.

Increasing anaphylaxis events in Western Australia identified using four linked administrative datasets

Background

Anaphylaxis events are increasing worldwide, based on studies of single administrative datasets including hospital admissions, emergency room presentations, and prescription and medical claims data. Linking multiple administrative datasets may provide better epidemiological estimates, by capturing a greater number of anaphylaxis events occurring at the individual level. In this linked data study in Western Australia, we combined 4 population-based datasets to identify anaphylaxis events, factors influencing occurrence, and change in event rates from 2002 to 2013.

Methods

Four linked administrative datasets from the Western Australian Data Linkage System were used, representing ambulance attendances, emergency department presentations, hospital inpatient admissions and death registrations. An anaphylaxis cohort was identified using ICD-9-CM, ICD-10-AM and additional anaphylaxis diagnosis codes, with event rates calculated. We explored the impact of age, gender, cause, Indigenous status and socioeconomic index on event rates. Standard Poisson regression models were used to examine the significance of the change in anaphylaxis event rates over time.

Results

A total 12,637 individuals (mean age 31.8 years, 49.6% female) experienced 15,462 anaphylaxis events between 2002 and 2013 (97.5% in non-Indigenous patients and 59.5% residing in the area of greatest socioeconomic advantage). Anaphylaxis event rates increased from 15.4 to 82.5/10⁵ population between 2002 and 2013. The greatest increase in anaphylaxis events was seen in those coded as unspecified anaphylaxis (all ages, males and females combined, p < 0.001), with the highest rates of unspecified anaphylaxis in males 0–4 years (171.9/10⁵ population in 2013), and females 15–19 years (104.0/10⁵ in 2013). The average annual percent increase (95% CI) for food-related anaphylaxis was 9.2% (6.6–12.0); for medication-related anaphylaxis was 5.8% (4.5–7.1); and for unspecified anaphylaxis was 10.4% (9.8–11.0); all p < 0.001. There was a significant increase in ambulance attendance, emergency presentations and inpatient admissions for anaphylaxis between 2002 and 2013, with emergency presentations (56.0/10⁵ population), inpatient admissions (43.2/10⁵), and ambulance attendance (21.6/10⁵) highest in 2013. Only 25 anaphylaxis-related deaths were recorded in the mortality register with no significant change in rates over time.

Conclusion

Using multiple linked administrative datasets, we identified significantly higher rates of total anaphylaxis than previously reported, with more than 5-fold increases in anaphylaxis events between 2002 and 2013. While the combination of 4 population-level datasets provides a more comprehensive capture of cases, even at the individual dataset level, admission rates for anaphylaxis in Western Australia are substantially higher than those previously reported for similar time periods, both in Australia and worldwide.

Association Between Use of Statins and Survival After Stroke: Real-World Data from The Australian Stroke Clinical Registry

IntroductionDespite being recommended in clinical guidelines for secondary prevention of stroke, there are limited real-world data on outcomes associated with use of statins post-stroke. Objectives and ApproachWe aimed to investigate the association between statin use and cardiovascular mortality post-stroke. We conducted a retrospective cohort study using prospectively collected data from the Australian Stroke Clinical Registry (2010-2014), linked with national medication dispensing and mortality data. We observed adult patients with first-ever ischaemic stroke or transient ischaemic attack (TIA) for 1-year following hospital discharge, or until their date of death, whichever occurred first. Statin use, defined as having an available statin dispensing, was assessed daily and treated as a time-varying exposure to account for patients who discontinued or reinitiated statins during follow-up. Multivariable, competing-risks regression, with non-cardiovascular death as the competing risk, was used to investigate the association between statin use and 1-year cardiovascular mortality. ResultsAmong 8363 patients discharged following first-ever ischaemic stroke or TIA (48% aged ≥75 years, 45% female, 20% TIA, median length-of-stay 5 days), 945 died within 1 year, with 763 deaths being cardiovascular-related. The proportion of statin users was 65% at 90 days, 64% at 180 days, and 62% at 1 year. Groups least likely to be statin users at 1-year were women (odds ratio [OR]: 0.75; 95% CI: 0.67-0.85), patients aged <65 years (OR: 0.80; 95% CI: 0.69-0.92), and those discharged directly home (OR: 0.77; 95% CI: 0.67-0.88). Compared to non-use, use of statins was associated with a reduced risk of cardiovascular mortality within 1 year overall (sub-distribution hazard ratio [SHR]: 0.40; 95% CI: 0.34-0.46), and in sub-groups of patients with TIA, severe stroke, and advanced age. Conclusion / Implications:Our preliminary data provide evidence of survival benefits associated with post-stroke statin use. Interventions to improve medication adherence may assist in reducing post-stroke mortality.

Using Linked Data to Explore the Association Between Statin Medicine Adherence and Hospitalisation Following A Large Patient Co-Payment Increase

IntroductionIn January 2005, the Australian Government increased the consumer medication co-payment by 21%. Previous research found that this affected population-level utilisation of statins, which fell by 5% following the co-payment increase. The subsequent health impact on individuals reducing or ceasing use of statins is unknown. Objectives and ApproachTo explore the two-year risk of acute coronary syndrome (ACS) or stroke-related hospitalisation among individuals who discontinued, reduced or continued statin medicines after the 2005 PBS co-payments increase. This was achieved through a retrospective cohort study using linked administrative Commonwealth and State datasets for the Western Australian population. Outcomes were assessed using the Fine and Gray competing risks method, with death as the competing risk, adjusting for demographics, comorbidities and medication history. ResultsThere were 207,066 individuals identified as using statins before the co-payment increase. After the increase, adherence reduced in 12.5% of this cohort, and 3.3% ceased use. There were 4,343 ACS and stroke-related hospitalisations for the cohort in the follow-up period. Multivariate analysis indicated ceasing statins increased the risk of hospitalisation for ACS or stroke-related events by 18% (95%CI=0.1-40%) compared to continuing therapy. The risk was greatest for males <70 years. No differences existed for women or older men who discontinued statins. There was no difference in hospitalisation risk for those who reduced statins compared to those who continued. Conclusion / ImplicationsYounger men ceasing statins after the 2005 co-payments increase had a higher risk of ACS and stroke hospitalisations compared to individuals who continued using statins. The findings highlight the importance of continued adherence to prescribed statin medication, and that discontinuing therapy for non-clinical reasons (such as cost) can have negative consequences. Additionally, it demonstrates to policymakers that substantial increases in consumer co-payments can result in adverse health outcomes.

Comparison of Time-Varying and Landmark Analysis Methods in Estimating the Association Between Medication Adherence and Outcomes: A Heart Failure Cohort

IntroductionMedication adherence is associated with a reduction of adverse outcomes in heart failure (HF). However, this association is complex to estimate accurately because adherence (exposure) can vary during the follow-up period. Adherence can be estimated as a fixed exposure to predict outcomes, and this is known as a landmark analysis. In contrast, adherence can also be estimated as a dynamic exposure which varies over time in the follow-up period. This is known as a time-varying analysis and is expected to be the more precise method. Objectives and ApproachWe compared these two methods in a HF cohort. We identified a population-based cohort of 3619 heart failure patients, aged 65-84 years hospitalised in Western Australia from 2003-2007 and who survived to 1-year post-discharge (landmark date). Adherence to renin-angiotensin system inhibitors (RASI) and β-blockers was calculated using proportion of days covered (PDC) expressed either as a fixed time exposure (in landmark analysis) or a varying exposure (in time-dependent analysis). The latter was updated every 30 days after the landmark date. Cox regression models were used to investigate the association between adherence and all-cause death at 1- and 3-years post-landmark date. ResultsFor 1-year outcomes, hazard ratios (HR) for every 10% increase in PDC were similar between models from landmark analyses (RASI adherence: 0.93, 0.90-0.97; β-blocker adherence: 0.96, 0.92-1.0) and time-dependent analyses (RASI adherence: 0.94, 0.91-0.97; β-blockers adherence: 0.95, 0.92 -0.99). However, 95% confidence intervals estimated from time-dependent models were narrower than those from landmark analyses. HRs were slightly closer to the null when estimated from time-dependent models. A similar pattern was seen with 3-year outcomes. Conclusion / ImplicationsTime-dependent analysis of adherence-outcome associations results in more precise estimates of hazard ratios. Estimates of HRs from landmark analysis models were similar but usually lower than those from time-dependent models.

Association Between Optimal Combination Pharmacotherapy and Survival After Stroke: A Registry and Pharmaceutical Dispensing Study

IntroductionTo prevent further vascular events, prescribing of multiple classes of medications (antihypertensive, antithrombotic and lipid-lowering) is recommended in national clinical guidelines following ischaemic stroke. Objectives and ApproachUsing real-world data, we determined the association between optimal combination pharmacotherapy (supply of all three classes, “optimal pharmacotherapy”) and survival after stroke. We linked a cohort of patients with first-ever ischaemic stroke from the Australian Stroke Clinical Registry (2010-2014) with national pharmaceutical dispensing and national mortality data. Cox regression was used to determine associations between pharmacotherapy in the first 30 days of stroke with 1-year (from day 31 to 395) all-cause mortality. All analyses were adjusted for socio-demographic (age, sex) and clinical characteristics (stroke severity, discharge destination). ResultsAmong 6684 patients discharged following first-ever ischaemic stroke (median length-of-stay 5 days), 6466 patients who survived to 30 days were included (44% female, median age 74 years). During the first 30 days from discharge, 71.4% received ≥1 medication class, and 32.9% (n=2125) received optimal pharmacotherapy. Patients with optimal pharmacotherapy were older (≥75 years 50.3% vs <75 years 44.5%; p<0.001), discharged directly home (home 58.5% vs other 40.3%; p<0.001) and experienced a less severe stroke (able to walk on admission 46.9% vs 36.4%; p<0.001), than those without optimal pharmacotherapy. Between day 31 and 395, there were 667 deaths; 530 related to cardiovascular disease. Compared to no medication, treatment with two medications was associated with a 42% lower risk of death (hazard ratio [HR]: 0.58; 95%CI: 0.45-0.73); and optimal pharmacotherapy had a 62% lower risk of death (HR: 0.38; 95% CI: 0.31-0.47). Survival was similar between those with one or no medication. Conclusion / ImplicationsPatients with ischaemic stroke who received optimal pharmacotherapy within 30-days of admission had greater one-year-survival. Further research is required to understand reasons for sub-optimal pharmacotherapy in these patients.

Frailty, and not medicines with anticholinergic or sedative effects, predicts adverse outcomes in octogenarians admitted for myocardial infarction: Population-level study

OBJECTIVE

To determine independent associations between the use of medicines with anticholinergic or sedative effects and frailty with outcomes of length of stay (LOS), coronary artery procedure performed and 30-day deaths in octogenarians admitted for a myocardial infarction (MI).

METHODS

We quantified patient exposure to medicines with anticholinergic or sedative effects using the drug burden index (DBI) and frailty using the hospital frailty risk score (HFRS). We used multivariable regression methods to determine the association between DBI and HFRS with outcomes of LOS, coronary artery procedures performed and 30-day deaths.

RESULTS

HFRS and not DBI score was significantly associated with receipt of coronary artery procedures (odds ratio [OR] 0.42; 95% CI 0.28-0.62 for high- versus low-risk groups) and 30-day deaths (OR 1.58; 95% CI 1.12-2.24 for high- versus low-risk groups).

CONCLUSION

Frailty risk is a more important predictor of outcomes than DBI score for octogenarians with an MI.

Overview of registries for anaphylaxis: a scoping review protocol

OBJECTIVE

This review will describe the scope and operational features of global registries for anaphylaxis and assess their contribution to improving knowledge and care of anaphylaxis by measuring their research output.

INTRODUCTION

The incidence of anaphylaxis is increasing around the world. Structured reporting systems, such as patient registries, are needed to better understand the burden of anaphylaxis and protect the growing number of allergic patients.

INCLUSION CRITERIA

The concept to be mapped is registries across the world that enroll patients who have experienced anaphylaxis. Published and gray literature sources will be considered if they describe the scope and operational features of anaphylaxis registries. Only full-text studies published in English will be included. There will be no date restriction.

METHODS

The JBI methodology for scoping reviews will be followed. Embase, MEDLINE, Scopus, and CINAHL will be searched from inception date for relevant articles. Identified keyword and index terms will be adapted for searches of gray literature sources, using Google advanced search functions. The authors and developers of identified registries will be contacted, where possible, to obtain additional information about the development and structure of systems. Data will be extracted by two independent reviewers. Any discrepancies will be resolved by a third reviewer. Tables and a narrative summary will be used to describe and compare the scope and features of anaphylaxis registries and outline their output to assess their contribution to research, clinical practice, and public health policy for anaphylaxis.

Patterns of Use and Discontinuation of Secondary Prevention Medications After Stroke

OBJECTIVE

To investigate whether certain patient, acute care, or primary care factors are associated with medication initiation and discontinuation in the community after stroke or TIA.

METHODS

This is a retrospective cohort study using prospective data on adult patients with first-ever acute stroke/TIA from the Australian Stroke Clinical Registry (April 2010 to June 2014), linked with nationwide medication dispensing and Medicare claims data. Medication users were those with ≥1 dispensing in the year postdischarge. Discontinuation was assessed among medication users and defined as having no medication supply for ≥90 days in the year postdischarge. Multivariable competing risks regression, accounting for death during the observation period, was conducted to investigate factors associated with time to medication discontinuation.

RESULTS

Among 17,980 registry patients with stroke/TIA, 91.4% were linked to administrative datasets. Of these, 9,817 adults with first-ever stroke/TIA were included (45.4% female, 47.6% aged ≥75 years, and 11.4% intracerebral hemorrhage). While most patients received secondary prevention medications (79.3% antihypertensive, 81.8% antithrombotic, and 82.7% lipid-lowering medication), between one-fifth and one-third discontinued treatment over the subsequent year postdischarge (20.9% antihypertensive, 34.1% antithrombotic, and 28.5% lipid-lowering medications). Prescription at hospital discharge (sub-hazard ratio [SHR] 0.70; 95% confidence interval [CI] 0.62-0.79), quarterly contact with a primary care physician (SHR 0.62; 95% CI 0.57-0.67), and prescription by a specialist physician (SHR 0.87; 95% CI 0.77-0.98) were all inversely associated with antihypertensive discontinuation.

CONCLUSIONS

Patterns of use of secondary prevention medications after stroke/TIA are not optimal, with many survivors discontinuing treatment within 1 year postdischarge. Improving postdischarge care for patients with stroke/TIA is needed to minimize unwarranted discontinuation.

Contemporary Incidence and Prevalence of Rheumatic Fever and Rheumatic Heart Disease in Australia Using Linked Data: The Case for Policy Change

Background In 2018, the World Health Organization prioritized control of acute rheumatic fever (ARF) and rheumatic heart disease (RHD), including disease surveillance. We developed strategies for estimating contemporary ARF/RHD incidence and prevalence in Australia (2015-2017) by age group, sex, and region for Indigenous and non-Indigenous Australians based on innovative, direct methods. Methods and Results This population-based study used linked administrative data from 5 Australian jurisdictions. A cohort of ARF (age <45 years) and RHD cases (<55 years) were sourced from jurisdictional ARF/RHD registers, surgical registries, and inpatient data. We developed robust methods for epidemiologic case ascertainment for ARF/RHD. We calculated age-specific and age-standardized incidence and prevalence. Age-standardized rate and prevalence ratios compared disease burden between demographic subgroups. Of 1425 ARF episodes, 72.1% were first-ever, 88.8% in Indigenous people and 78.6% were aged <25 years. The age-standardized ARF first-ever rates were 71.9 and 0.60/100 000 for Indigenous and non-Indigenous populations, respectively (age-standardized rate ratio=124.1; 95% CI, 105.2-146.3). The 2017 Global Burden of Disease RHD prevalent counts for Australia (<55 years) underestimate the burden (1518 versus 6156 Australia-wide extrapolated from our study). The Indigenous age-standardized RHD prevalence (666.3/100 000) was 61.4 times higher (95% CI, 59.3-63.5) than non-Indigenous (10.9/100 000). Female RHD prevalence was double that in males. Regions in northern Australia had the highest rates. Conclusions This study provides the most accurate estimates to date of Australian ARF and RHD rates. The high Indigenous burden necessitates urgent government action. Findings suggest RHD may be underestimated in many high-resource settings. The linked data methods outlined here have potential for global applicability.

Screening and treating pre-operative anaemia and suboptimal iron stores in elective colorectal surgery: a cost effectiveness analysis

Our study investigated whether pre-operative screening and treatment for anaemia and suboptimal iron stores in a patient blood management clinic is cost effective. We used outcome data from a retrospective cohort study comparing colorectal surgery patients admitted pre- and post-implementation of a pre-operative screening programme. We applied propensity score weighting techniques with multivariable regression models to adjust for differences in baseline characteristics between groups. Episode-level hospitalisation costs were sourced from the health service clinical costing data system; the economic evaluation was conducted from a Western Australia Health System perspective. The primary outcome measure was the incremental cost per unit of red cell transfusion avoided. We compared 441 patients screened in the pre-operative anaemia programme with 239 patients not screened; of the patients screened, 180 (40.8%) received intravenous iron for anaemia and suboptimal iron stores. The estimated mean cost of screening and treating pre-operative anaemia was AU$332 (£183; US$231; €204) per screened patient. In the propensity score weighted analysis, screened patients were transfused 52% less red cell units when compared with those not screened (rate ratio = 0.48, 95%CI 0.36-0.63, p < 0.001). The mean difference in total screening, treatment and hospitalisation cost between groups was AU$3776 lower in the group screened (£2080; US$2629; €2325) (95%CI AU$1604-5947, p < 0.001). Screening elective patients pre-operatively for anaemia and suboptimal iron stores reduced the number of red cell units transfused. It also resulted in lower total costs than not screening patients, thus demonstrating cost effectiveness.

Assuming one dose per day yields a similar estimate of medication adherence in patients with stroke: An exploratory analysis using linked registry data

PURPOSE

Prescribed daily dose (PDD), the number of doses prescribed to be taken per day, is used to calculate medication adherence using pharmacy claims data. PDD can be substituted by (i) one dose per day (1DD), (ii) an estimate based on the 75th percentile of days taken by patients to refill a script (PDD₇₅ ) or (iii) the World Health Organization's defined daily dose (DDD). We aimed to compare these approaches for estimating the duration covered by medications and whether this affects calculated 1-year adherence to antihypertensive medications post-stroke.

METHODS

We conducted a retrospective review of prospective cohort data from the ongoing Australian Stroke Clinical Registry linked with pharmacy claims data. Adherence was calculated as the proportion of days covered (PDC) for 1DD, PDD₇₅ and DDD. Differences were assessed using Wilcoxon rank-sum tests.

RESULTS

Among 12 628 eligible patients with stroke, 10 057 (80%) were prescribed antihypertensive medications in the year after hospital discharge (78.2% aged ≥65 years, 45.2% female). Overall, the 75th percentile of patient time until next medication refill was 39 days. The greatest variations in dose regimens, estimated using person- and dose-level refill times, were for beta blockers (11.4% taking two tablets/day). There were comparable levels of adherence between 1DD and the PDD₇₅ (median PDC 91.0% vs 91.2%; P = 0.70), but adherence was slightly higher using DDD (92.3%; both P < 0.001). However, this would represent a clinically nonsignificant difference.

CONCLUSION

Adherence to antihypertensive medications shows similar estimates across standard measures of dosage in patients during the first year after an acute stroke.

Systematic reviews and meta-analyses comparing mortality in restrictive and liberal haemoglobin thresholds for red cell transfusion: an overview of systematic reviews

BACKGROUND

There are no overviews of systematic reviews investigating haemoglobin thresholds for transfusion. This is important as the literature on transfusion thresholds has grown considerably in recent years. Our aim was to synthesise evidence from systematic reviews and meta-analyses of the effects of restrictive and liberal transfusion strategies on mortality.

METHODS

This was a systematic review of systematic reviews (overview). We searched MEDLINE, Embase, Web of Science Core Collection, PubMed, Google Scholar, and the Joanna Briggs Institute EBP Database, from 2008 to 2018. We included systematic reviews and meta-analyses of randomised controlled trials comparing mortality in patients assigned to red cell transfusion strategies based on haemoglobin thresholds. Two independent reviewers extracted data and assessed methodological quality. We assessed the methodological quality of included reviews using AMSTAR 2 and the quality of evidence pooled using an algorithm to assign GRADE levels.

RESULTS

We included 19 systematic reviews reporting 33 meta-analyses of mortality outcomes from 53 unique randomised controlled trials. Of the 33 meta-analyses, one was graded as high quality, 15 were moderate, and 17 were low. Of the meta-analyses presenting high- to moderate-quality evidence, 12 (75.0%) reported no statistically significant difference in mortality between restrictive and liberal transfusion groups and four (25.0%) reported significantly lower mortality for patients assigned to a restrictive transfusion strategy. We found few systematic reviews addressed clinical differences between included studies: variation was observed in haemoglobin threshold concentrations, the absolute between group difference in haemoglobin threshold concentration, time to randomisation (resulting in transfusions administered prior to randomisation), and transfusion dosing regimens.

CONCLUSIONS

Meta-analyses graded as high to moderate quality indicate that in most patient populations no difference in mortality exists between patients assigned to a restrictive or liberal transfusion strategy.

TRIAL REGISTRATION

PROSPERO CRD42019120503.

Long-Term Adherence to Renin-Angiotensin System Inhibitors and β-Blockers After Heart Failure Hospitalization in Senior Patients

AIMS

We investigated long-term adherence to renin-angiotensin system inhibitors (RASIs) and β-blockers, and associated predictors, in senior patients after hospitalization for heart failure (HF).

METHODS

A population-based data set identified 4488 patients who survived 60 days following their index hospitalization for HF in Western Australia from 2003 to 2008 with a 3-year follow-up. Their person-linked Pharmaceutical Benefits Scheme records identified medications dispensed during follow-up. Drug discontinuation was defined as the first break ≥90 days following the previous supply. Medication adherence was calculated using the proportion of days covered (PDC), with PDC ≥ 80% defined as being adherent. Multivariable logistic regression models were used to identify predictors of PDC < 80%.

RESULTS

In the cohort (57% male, mean age: 76.6 years), 77.4% were dispensed a RASI and 52.7% a β-blocker within 60 days postdischarge. Over the 3-year follow-up, 28% and 42% of patients discontinued RASI and β-blockers, respectively. Only 64.6% and 47.5% of RASI and β-blocker users, respectively, were adherent to their treatment over 3 years, with adherence decreasing over time (trend P < .0001 for RASI and trend P = .02 for β-blockers). Older age, increasing Charlson comorbidity score, chronic kidney disease, and chronic obstructive pulmonary disease were independent predictors of PDC < 80% for both drug groups.

CONCLUSION

Among seniors hospitalized for HF, discontinuation gaps were common for RASI and β-blockers postdischarge, and long-term adherence to these medications was suboptimal. Where appropriate, strategies to improve long-term medication adherence are indicated in HF patients, particularly in elderly patients with comorbidities.

Frequent general practitioner visits are protective against statin discontinuation after a Pharmaceutical Benefits Scheme copayment increase

Objective This study assessed the effect of the frequency of general practitioner (GP) visitation in the 12 months before a 21% consumer copayment increase in the Pharmaceutical Benefits Scheme (PBS; January 2005) on the reduction or discontinuation of statin dispensing for tertiary prevention. Methods The study used routinely collected, whole-population linked PBS, Medicare, mortality and hospital data from Western Australia. From 2004 to 2005, individuals were classified as having discontinued, reduced or continued their use of statins in the first six months of 2005 following the 21% consumer copayment increase on 1 January 2005. The frequency of GP visits was calculated in 2004 from Medicare data. Multivariate logistic regression models were used to determine the association between GP visits and statin use following the copayment increase. Results In December 2004, there were 22495 stable statin users for tertiary prevention of prior coronary heart disease, prior stroke or prior coronary artery revascularisation procedure. Following the copayment increase, patients either discontinued (3%), reduced (12%) or continued (85%) their statins. Individuals who visited a GP three or more times in 2004 were 47% less likely to discontinue their statins in 2005 than people attending only once. Subgroup analysis showed the effect was apparent in men, and long-term or new statin users. The frequency of GP visits did not affect the proportion of patients reducing their statin therapy. Conclusions Patients who visited their GP at least three times per year had a lower risk of ceasing their statins in the year following the copayment increase. GPs can help patients maintain treatment following rises in medicines costs. What is known about the topic? Following the 21% increase in medication copayment in 2005, individuals discontinued or reduced their statin usage, including for tertiary prevention. What does this paper add? Patients who visited their GP at least three times per year were less likely to discontinue their statin therapy for tertiary prevention following a large copayment increase. What are the implications for practitioners? This paper identifies the important role that GPs have in maintaining the continued use of important medications following rises in medicines costs.

Rheumatic heart disease in pregnancy: Profile of women admitted to a Western Australian tertiary obstetric hospital

This retrospective study assessed maternal and perinatal outcomes for women with rheumatic heart disease (RHD) admitted to the largest tertiary obstetric hospital in Western Australia from 2009 to 2016. Of 54 women identified, 75.9% were Indigenous, 59.3% lived in rural areas and 40.7% had severe RHD. Heart failure developed in 10% who gave birth. Indigenous women were younger, had higher gravidity (P = 0.0305), were more likely to receive secondary prophylaxis (P = 0.0041) and have sub-optimal antenatal clinic attendance (P = 0.0078). There were no maternal deaths and two perinatal deaths (4.0%), reflecting vigilance in the obstetric management of women with RHD in Western Australia.

The End Rheumatic Heart Disease in Australia Study of Epidemiology (ERASE) Project: data sources, case ascertainment and cohort profile

PURPOSE

Acute rheumatic fever (ARF) and rheumatic heart disease (RHD) persist as public health issues in developing countries and among disadvantaged communities in high-income countries, with rates in Aboriginal and Torres Strait Islander peoples in Australia among the highest recorded globally. A robust evidence base is critical to support policy recommendations for eliminating RHD, but available data are fragmented and incomplete. The End RHD in Australia: Study of Epidemiology (ERASE) Project aims to provide a comprehensive database of ARF and RHD cases in Australia as a basis for improved monitoring and to assess prevention and treatment strategies. The objective of this paper is to describe the process for case ascertainment and profile of the study cohort.

PATIENTS AND METHODS

The ERASE database has been built using linked administrative data from RHD registers, inpatient hospitalizations, and death registry data from 2001 to 2017 (mid-year). Additional linked datasets are available. The longitudinal nature of the data is harnessed to estimate onset and assess the progression of the disease. To accommodate systematic limitations in diagnostic coding for RHD, hospital-only identified RHD has been determined using a purposefully developed prediction model.

RESULTS

Of 132,053 patients for whom data were received, 42,064 are considered true cases of ARF or RHD in the study period. The patient population under 60 years in the compiled dataset is more than double the number of patients identified in ARF/RHD registers (12,907 versus 5049). Non-registered patients were more likely to be older, non-Indigenous, and at a later disease stage.

CONCLUSION

The ERASE Project has created an unprecedented linked administrative database on ARF and RHD in Australia. These data provide a critical baseline for efforts to end ARF/RHD in Australia. The methodological work conducted to compile this database resulted in significant improvements in the robustness of epidemiological estimates and entails valuable lessons for ARF/RHD research globally.

Bowel patterns, gastrointestinal symptoms, and emotional well-being in adolescents: A cohort study

BACKGROUND AND AIM

Bowel patterns are varied in the general population. Gastrointestinal symptoms are common reasons for clinical visits. We aimed to examine the usual bowel pattern and the prevalence and significance of gastrointestinal symptoms in a population-based cohort of Australian adolescents.

METHODS

Seventeen-year-old adolescents (n = 1279) in the Western Australian Pregnancy Cohort (Raine) Study participated in a cross-sectional assessment, involving health questionnaires. Questions included medical history, diet, bowel patterns, and gastrointestinal symptoms. Data were analyzed to identify patterns of bowel motions, gastrointestinal symptoms, and factors associated with these in adolescents. Multivariate logistic regression analysis was used to determine predictors of poorer self-rated health status.

RESULTS

The dominant pattern of bowel motions was passage of stool that was "not too hard and not too soft" (Bristol stool types 3 and 4) in 90% and occurring between three and seven times per week in 74%. The most prevalent gastrointestinal symptoms included abdominal bloating (72%), abdominal pain (36%), nausea (25%), and constipation (20%). A "Western" dietary pattern was associated with abdominal bloating, constipation, and nausea (P < 0.05). Apart from diarrhea, gastrointestinal symptoms were more prevalent in female adolescents than male adolescents (P < 0.05 for all). Female sex (odds ratio [OR] 1.87, 95% confidence interval [CI] 1.16-3.02, P = 0.01), nausea (OR 3.18, 95% CI 2.03-4.98, P < 0.001), and depression (OR 6.68, 95% CI 3.65-12.22, P = 0.03) were independently associated with poorer self-rated health status, after adjusting for other gastrointestinal symptoms.

CONCLUSIONS

In adolescents, bowel patterns and gastrointestinal symptoms are diverse and show sex differences. Nausea, depression, and female sex are significant factors for poorer self-rated health.

Systematic reviews and meta-analyses comparing mortality in restrictive and liberal haemoglobin thresholds for red cell transfusion: protocol for an overview of systematic reviews

INTRODUCTION

There has been a significant increase in the number of systematic reviews and meta-analyses of randomised controlled trials investigating thresholds for red blood cell transfusion. To systematically collate, appraise and synthesise the results of these systematic reviews and meta-analyses, we will conduct an overview of systematic reviews.

METHODS AND ANALYSIS

This is a protocol for an overview of systematic reviews. We will search five databases: MEDLINE, Embase, Web of Science Core Collection, PubMed (for prepublication, in process and non-Medline records) and Google Scholar. We will consider systematic reviews and meta-analyses of randomised controlled trials evaluating the effect of haemoglobin thresholds for red blood cell transfusion on mortality. Two authors will independently screen titles and abstracts retrieved in the literature search and select studies meeting the eligibility criteria for full-text review. We will extract data onto a predefined form designed to summarise the key characteristics of each review. We will assess the methodological quality of included reviews and the quality of evidence in included reviews.

ETHICS AND DISSEMINATION

Formal ethics approval is not required for this overview as we will only analyse published literature. The findings of this study will be presented at relevant conferences and submitted for peer-review publication. The results are likely to be used by clinicians, policy makers and developers of clinical guidelines and will inform suggestions for future systematic reviews and randomised controlled trials.

PROSPERO REGISTRATION NUMBER

CRD42019120503.