Differing Definitions of First-Ever Stroke Influence Incidence Estimates More than Trends: A Study Using Linked Administrative Data

INTRODUCTION

Researchers apply varying definitions when measuring stroke incidence using administrative data. We aimed to investigate the sensitivity of incidence estimates to varying definitions of stroke and lookback periods and to provide updated incidence rates and trends for Western Australia (WA).

METHODS

We used linked state-wide hospital and death data from 1985 to 2017 to identify incident strokes from 2005 to 2017. A standard definition was applied which included strokes coded as the principal hospital diagnosis or the underlying cause of death, with a 10-year lookback used to clear prevalent cases. Alternative definitions were compared against the standard definition by percentage difference in case numbers. Age-standardised incidence rates were calculated, and age- and sex-adjusted Poisson regression models were used to estimate incidence trends.

RESULTS

The standard definition with a 10-year lookback period captured 31,274 incident strokes. Capture increased by 19.3% when including secondary diagnoses, 4.1% when including nontraumatic subdural and extradural haemorrhage, and 8.1% when including associated causes of death. Excluding death records reduced capture by 11.1%. A 20-year lookback reduced over-ascertainment by 2.0%, and a 1-year lookback increased capture by 13.3%. Incidence declined 0.6% annually (95% confidence interval -0.9, -0.3). Annual reductions were similar for most definitions except when death records were excluded (-0.1%, CI: -0.4, 0.2) and with the shortest lookback periods (greatest annual reduction).

CONCLUSION

Stroke incidence has declined in WA. Differing methods of identifying stroke influence estimates of incidence to a greater extent than estimates of trends. Reductions in stroke incidence over time are primarily driven by declines in fatal strokes.

Mortality and cause of death during inpatient psychiatric care in New South Wales, Australia: A retrospective linked data study

BACKGROUND

Premature mortality in people with mental illness is well-documented, yet deaths during inpatient psychiatric care have received little research attention. This study investigates mortality rates and causes of death during inpatient psychiatric care in New South Wales (NSW), Australia. Risk factors for inpatient death were also explored.

METHODS

A retrospective cohort study using linked administrative datasets with complete capture of psychiatric admissions in NSW from 2002 to 2012 (n = 421,580) was conducted. Univariate and multivariate random-effects logistic regression analyses were used to explore risk factors for inpatient death.

RESULTS

The mortality rate during inpatient psychiatric care was 1.12 deaths per 1000 episodes of care and appeared to decline over the study period. Suicide accounted for 17% of inpatient deaths, while physical health causes accounted for 75% of all deaths. Thirty percent of these deaths were considered potentially avoidable. In the multivariate model, male sex, unknown address and several physical health diagnoses were associated with increased deaths.

CONCLUSIONS

The mortality rate and number of avoidable deaths during inpatient psychiatric care were substantial and warrant further systemic investigation. This was driven by a dual burden of physical health conditions and suicide. Strategies to improve access to physical health care on psychiatric inpatient wards and prevent inpatient suicide are necessary. A coordinated approach to monitoring psychiatric inpatient deaths in Australia is not currently available and much needed.

Opportunities for prevention: a data-linkage study to inform a public health response to youth offending in the Northern Territory, Australia

BACKGROUND

Numerous studies have demonstrated a strong link between child maltreatment and subsequent youth offending, leading to calls for early intervention initiatives. However, there have been few whole-population studies into the dimensions of statutory child maltreatment responses that can inform these programs. The aim of this study was to investigate the sex-specific association between level and timing of child protection system (CPS) contact and youth offending.

METHODS

This retrospective cohort study used linked individual-level records from multiple agencies, for 10,438Aboriginal children born in the Northern Territory between 1999 and 2006. The outcome measure was the first alleged offence. Key explanatory variables were level (no contact through to out-of-home care) and timing (0-4 years, 5-9 years, or both) of CPS contact. The Kaplan-Meier method was used to estimate cumulative incidence and a flexible parametric survival model to estimate hazard ratios (HR).

RESULTS

Children with no record of CPS contact before age 10 had the lowest cumulative incidence of first alleged offence by age 18 (boys: 23.4% [95%CI:21.0-26.1]; girls: 6.6% [95%CI:5.3-8.2]) and those with a record of out-of-home care the highest CI (boys: 45.5% [95%CI:37.0-54.9]; girls: 18.6% [95%CI:13.0-26.2]). The association of CPS contact with the relative risk of a first alleged offence was greatest for children aged 10-13 years and decreased with age. Timing of CPS contact was also associated with increasing cumulative incidence. The relative risk for first alleged offence was generally higher for children with CPS contact, of any type, during both developmental phases including notifications during both phases (boys, HR at age 11: 8.9 [95%CI:4.2-17.2]; girls, HR at age 11: 13.7 [95%CI:3.8-48.9]) and substantiations during both phases (boys, HR at age 11: 17.0 [95%CI:9.6-30.0]; girls, HR at age 11: 54.1 [95%CI:18.1-162]).

CONCLUSION

The increased risk of offending associated with level and timing of early CPS contact highlights opportunities for a differentiated public health response to improve life trajectories for children and to reduce youth crime. Although children with unsubstantiated notifications of maltreatment do not meet the criteria for a statutory CPS response, the higher risk of offending among these children supports their inclusion in targeted preventive interventions.

Community perspectives on the benefits and risks of technologically enhanced communicable disease surveillance systems: a report on four community juries

Background

Outbreaks of infectious disease cause serious and costly health and social problems. Two new technologies – pathogen whole genome sequencing (WGS) and Big Data analytics – promise to improve our capacity to detect and control outbreaks earlier, saving lives and resources. However, routinely using these technologies to capture more detailed and specific personal information could be perceived as intrusive and a threat to privacy.

Method

Four community juries were convened in two demographically different Sydney municipalities and two regional cities in New South Wales, Australia (western Sydney, Wollongong, Tamworth, eastern Sydney) to elicit the views of well-informed community members on the acceptability and legitimacy of:

making pathogen WGS and linked administrative data available for public health research

using this information in concert with data linkage and machine learning to enhance communicable disease surveillance systems

Fifty participants of diverse backgrounds, mixed genders and ages were recruited by random-digit-dialling and topic-blinded social-media advertising. Each jury was presented with balanced factual evidence supporting different expert perspectives on the potential benefits and costs of technologically enhanced public health research and communicable disease surveillance and given the opportunity to question experts.

Results

Almost all jurors supported data linkage and WGS on routinely collected patient isolates for the purposes of public health research, provided standard de-identification practices were applied. However, allowing this information to be operationalised as a syndromic surveillance system was highly contentious with three juries voting in favour, and one against by narrow margins. For those in favour, support depended on several conditions related to system oversight and security being met. Those against were concerned about loss of privacy and did not trust Australian governments to run secure and effective systems.

Conclusions

Participants across all four events strongly supported the introduction of data linkage and pathogenomics to public health research under current research governance structures. Combining pathogen WGS with event-based data surveillance systems, however, is likely to be controversial because of a lack of public trust, even when the potential public health benefits are clear. Any suggestion of private sector involvement or commercialisation of WGS or surveillance data was unanimously rejected.

The link between hearing impairment and child maltreatment among Aboriginal children in the Northern Territory of Australia: is there an opportunity for a public health approach in child protection?

Background

International studies provide evidence of an association between child disabilities, including hearing impairment (HI), and child maltreatment. There are high prevalences of ear disease with associated HI, and child maltreatment among Australian Aboriginal children, but the link between HI and child maltreatment is unknown. This study investigates the association between HI and child maltreatment for Aboriginal children living in the Northern Territory (NT) of Australia.

Methods

This was a retrospective cohort study of 3895 Aboriginal school-aged children (born between 1999 and 2008) living in remote NT communities. The study used linked individual-level information from health, education and child protection services. The outcome variables were child maltreatment notifications and substantiations. The key explanatory variable, HI, was based on audiometric assessment. The Kaplan–Meier estimator method was used in univariate analysis; Cox proportional hazards regression was used in multivariable analysis.

Results

A majority of the study cohort lived in very remote (94.5%) and most disadvantaged (93.1%) regions. Among all children in the study cohort, 56.1% had a record of either HI or unilateral hearing loss (UHL), and for those with a history of contact with child protection services (n = 2757), 56.7% had a record of HI/UHL (n = 1564). In the 1999–2003 birth cohort, by age 12 years, 53.5% of children with a record of moderate or worse HI had at least one maltreatment notification, compared to 47.3% of children with normal hearing. In the 2004–2008 cohort, the corresponding results were 83.4 and 71.7% respectively. In multivariable analysis, using the full cohort, children with moderate or worse HI had higher risk of any child maltreatment notification (adjusted Hazard Ratios (adjHR): 1.16, 95% CI:1.04–1.30), notification for neglect (adjHR:1.17, 95% CI:1.04–1.31) and substantiation (adjHR:1.20, 95% CI:1.04–1.40), than children with normal hearing. In the 2004–2008 birth cohort, children with moderate or worse HI had higher risk of a substantiated episode of physical abuse (adjHR:1.47, 95% CI:1.07–2.03) than children with normal hearing.

Conclusion

Our findings demonstrate the urgent need for HI and child maltreatment prevention strategies through raised community awareness and inter-agency collaboration. Effective information-sharing between service providers is a critical first step to a public health approach in child protection.

Hearing and justice: The link between hearing impairment in early childhood and youth offending in Aboriginal children living in remote communities of the Northern Territory, Australia

BACKGROUND

High prevalence of chronic middle ear disease has persisted in Australian Aboriginal children, and the related hearing impairment (HI) has been implicated in a range of social outcomes. This study investigated the association between HI in early childhood and youth offending.

METHOD

This was a retrospective cohort study of 1533 Aboriginal children (born between 1996 and 2001) living in remote Northern Territory communities. The study used linked individual-level information from health, education, child protection and youth justice services. The outcome variable was a youth being "found guilty of an offence". The key explanatory variable, hearing impairment, was based on audiometric assessment. Other variables were: child maltreatment notifications, Year 7 school enrolment by mother, Year 7 school attendance and community 'fixed- effects'. The Cox proportional hazards model was used to estimate the association between HI and youth offending; and the Royston R2 measure to estimate the separate contributions of risk factors to youth offending.

RESULTS

The proportion of hearing loss was high in children with records of offence (boys: 55.6%, girls: 36.7%) and those without (boys: 46.1%; girls: 49.0%). In univariate analysis, a higher risk of offending was found among boys with moderate or worse HI (HR: 1.77 [95% CI: 1.05-2.98]) and mild HI (HR: 1.54 [95% CI:1.06-2.23]). This association was attenuated in multivariable analysis (moderate HI, HR: 1.43 [95% CI:0.78-2.62]; mild HI, HR: 1.37 [95% CI: 0.83-2.26]). No evidence for an association was found in girls. HI contributed 3.2% and 6.5% of variation in offending among boys and girls respectively. Factors contributing greater variance included: community 'fixed-effects' (boys: 14.6%, girls: 36.5%), child maltreatment notification (boys: 14.2%, girls: 23.9%) and year 7 school attendance (boys: 7.9%; girls 12.1%). Enrolment by mother explained substantial variation for girls (25.4%) but not boys (0.2%).

CONCLUSION

There was evidence, in univariate analysis, for an association between HI and youth offending for boys however this association was not evident after controlling for other factors. Our findings highlight a range of risk factors that underpin the pathway to youth-offending, demonstrating the urgent need for interagency collaboration to meet the complex needs of vulnerable children in the Northern Territory.

Mortality in hospital patients with and without mental disorders: A data-linkage cohort study

OBJECTIVE

In the general population, people with mental disorders have increased mortality. This association, however, has not been explored in a population who at some time were inpatients of a public hospital.

METHODS

The sampling frame was patients admitted to an Australian regional public hospital 1996-2010. Those with known mental disorder were compared with an equal number of randomly selected patients without known mental disorder, matched for age, sex, and year of admission. Mortality outcomes were determined by linkage of hospital data and the National Death Index.

RESULTS

We identified 15,356 patients with mental disorder and 15,356 without known mental disorder, 25.2% of the former and 17.3% of the latter died during the study period. The odds ratio (OR) for death in those with mental disorder was 2.20 (95% confidence interval: 2.01-2.41) after adjusting for confounders, and their mean age at death was 4.6 years younger (p < 0.001). Other independent risk factors for mortality were being Indigenous (OR 1.72, 1.32-2.24), not partnered (OR 1.55, 1.36-1.76) or having multiple comorbidities (OR 1.65, 1.43-1.90). In the model that included multiple interactions, the ORs for death in Indigenous patients with mental disorder were markedly higher (6.6-9.5), regardless of other risk factors.

DISCUSSION

Among patients with a history of public hospital admission, those with mental disorders have higher mortality than those without mental disorders. This gap in life expectancy mandates increased attention, by clinicians and health services alike, to preventable causes of death in people with mental illness.

Impact of consumer copayments for subsidised medicines on health services use and outcomes: a protocol using linked administrative data from Western Australia

INTRODUCTION

Across the world, health systems are adopting approaches to manage rising healthcare costs. One common strategy is a medication copayments scheme where consumers make a contribution (copayment) towards the cost of their dispensed medicines, with remaining costs subsidised by the health insurance service, which in Australia is the Federal Government.In Australia, copayments have tended to increase in proportion to inflation, but in January 2005, the copayment increased substantially more than inflation. Results from aggregated dispensing data showed that this increase led to a significant decrease in the use of several medicines. The aim of this study is to determine the demographic and clinical characteristics of individuals ceasing or reducing statin medication use following the January 2005 Pharmaceutical Benefit Scheme (PBS) copayment increase and the effects on their health outcomes.

METHODS AND ANALYSIS

This whole-of-population study comprises a series of retrospective, observational investigations using linked administrative health data on a cohort of West Australians (WA) who had at least one statin dispensed between 1 May 2002 and 30 June 2010. Individual-level data on the use of pharmaceuticals, general practitioner (GP) visits, hospitalisations and death are used.This study will identify patients who were stable users of statin medication in 2004 with follow-up commencing from 2005 onwards. Subgroups determined by change in adherence levels of statin medication from 2004 to 2005 will be classified as continuation, reduction or cessation of statin therapy and explored for differences in health outcomes and health service utilisation after the 2005 copayment change.

ETHICS AND DISSEMINATION

Ethics approvals have been obtained from the Western Australian Department of Health (#2007/33), University of Western Australia (RA/4/1/1775) and University of Notre Dame (0 14 167F). Outputs from the findings will be published in peer reviewed journals designed for a policy audience and presented at state, national and international conferences.