Reducing rip current drowning: An improved residual based lightweight deep architecture for rip detection.

Rip Currents are contributing around 25 fatal drownings each year in Australia. Previous research has indicated that most of beachgoers cannot correctly identify a rip current, leaving them at risk of experiencing a drowning incident. Automated detection of rip currents could help to reduce drownings and assist lifeguards in supervision planning; however, varying beach conditions have made this challenging. This work presents the effectiveness of an improved lightweight framework for detecting rip currents: RipDet+1, aided with residual mapping to boost the generalization performance. We have used Yolo-V3 architecture to build RipDet+ framework and utilize pretrained weight by fully exploiting the detection training set from some base classes which in result quickly adapt the detection prediction to the available rip data. Extensive experiments are reported which show the effectiveness of RipDet+ architecture in achieving a detection accuracy of 98.55%, which is significantly greater compared to other state-of-the-art methods for Rip currents detection.

Validation of ICD-10-AM Coding for Myocardial Infarction Subtype in Hospitalisation Data.

BACKGROUND: International Classification of Disease (ICD) codes are central for identifying myocardial infarction (MI) in administrative hospitalisation data, however validation of MI subtype codes is limited. We measured the sensitivity and specificity of ICD-10-AM (Australian Modification) codes for ST-elevation MI (STEMI) and non-STEMI (NSTEMI). METHODS: A sample of MI admissions was obtained from a dataset containing all MI hospitalisations in Western Australia (WA) for 2003, 2008 and 2013. Clinical data were collected from hospital medical records (n=799 patients). Cases were classified by ICD-10-AM codes for STEMI, NSTEMI and unspecified MI, and compared to clinical classification from review of available electrocardiographs (ECGs) and cardiac biomarkers (n=660). Sensitivity and specificity for ICD-10-AM coding versus clinical classification was measured, stratified by calendar year of discharge. RESULTS: The majority of classifiable cases had MI recorded in the principal diagnosis field (STEMI n=293, 84.2%; NSTEMI n=202, 74.3%; unspecified MI n=20, 50.0%). Overall sensitivity of the ICD-10-AM STEMI code was 86.3% (95% CI 81.7-90.0%) and was higher when restricted to MI as a principal versus secondary diagnosis (88.8% vs 66.7%). Comparable values for NSTEMI were 66.7% (95% CI 61.5-71.6%), and 68.8% vs 61.4% respectively. Between 2003 and 2013, sensitivity for both MI subtypes increased: 80.2-89.5% for STEMI, and 51.2-73.8% for NSTEMI. Specificity was high for NSTEMI throughout (88.2% 95% CI 84.1-91.6%), although improving over time for STEMI (68.1-76.4%). CONCLUSIONS: The sensitivity and specificity of ICD-10-AM codes for MI subtypes in hospitalisation data are generally high, particularly for principal diagnosis cases. However, the temporal improvement in sensitivity in coding of MI subtypes, particularly NSTEMI, may necessitate modification to trend studies using administrative hospitalisation data.

In Vivo Half-Life Extension of BMP1/TLL Metalloproteinase Inhibitors Using Small-Molecule Human Serum Albumin Binders.

Reducing the required frequence of drug dosing can improve the adherence of patients to chronic treatments. Hence, drugs with longer in vivo half-lives are highly desirable. One of the most promising approaches to extend the in vivo half-life of drugs is conjugation to human serum albumin (HSA). In this work, we describe the use of AlbuBinder 1, a small-molecule noncovalent HSA binder, to extend the in vivo half-life and pharmacology of small-molecule BMP1/TLL inhibitors in humanized mice (HSA KI/KI). A series of conjugates of AlbuBinder 1 with BMP1/TLL inhibitors were prepared. In particular, conjugate c showed good solubility and a half-life extension of >20-fold versus the parent molecule in the HSA KI/KI mice, reaching half-lives of >48 h with maintained maximal inhibition of plasma BMP1/TLL. The same conjugate showed a half-life of only 3 h in the wild-type mice, suggesting that the half-life extension was principally due to specific interactions with HSA. It is envisioned that conjugation to AlbuBinder 1 should be applicable to a wide range of small molecule or peptide drugs with short half-lives. In this context, AlbuBinders represent a viable alternative to existing half-life extension technologies.

The Wittenoom legacy.

The Wittenoom crocidolite (blue asbestos) mine and mill ceased operating in 1966. The impact of this industry on asbestos-related disease in Western Australia has been immense. Use of the employment records of the Australian Blue Asbestos Company and records of the Wittenoom township residents has permitted two cohorts of people with virtually exclusive exposure to crocidolite to be assembled and studied. Follow-up of these two cohorts has been conducted through data linkage with available hospital, mortality and cancer records. The evolution of asbestos-related disease has been recorded and, with the establishment of exposure measurements, quantitative exposure-response relationships have been estimated. There has been an ongoing epidemic of mortality from lung cancer and malignant mesothelioma and, less so, from asbestosis. Wittenoom crocidolite was used extensively in asbestos-cement products in Western Australia. As a result, the state has recorded a higher malignant-mesothelioma mortality rate than in any other Australian state and in any defined general population in the world. Thus, the legacy of Wittenoom has extended beyond the mine and the town, and is still evident more than 50 years after the closure of the mine.

Controlled Delivery of Dutasteride Using Dissolvable Microarrays: Initial Formulation and In Vivo Evaluation.

Dutasteride is prescribed as a once-daily oral capsule for the treatment of symptomatic benign prostatic hyperplasia. As an alternative and patient-focused drug product, this laboratory evaluated the potential to deliver dutasteride in a controlled/sustained manner when formulated as a microarray. The low oral dose, low aqueous solubility, and slow rate of elimination of dutasteride were considered ideal properties which may enable a once-weekly microarray option for patients. The concept of sustained release was initially proven in mini-pigs whereby simple intradermal administration of a nanomilled dutasteride suspension (0.12 mg/kg) was associated with an exposure period of at least 1 month. Dissolvable microarrays were successfully manufactured using a nanomilled suspension and were administered to rats at doses up to 0.32 mg/kg. In these studies, serum dutasteride was quantifiable for approximately 2 weeks after a single application. In silico modeling of the rat data using a two-compartment intradermal model was conducted and predicted that, in humans, a once-weekly dose of 2 mg, given as a microarray, could deliver cumulative and therapeutically relevant levels of dutasteride in a manner which is comparable to that observed with the current oral regimen.

The usefulness of a novel patient management decision aid to improve clinical decision-making skills in final year chiropractic students.

Background: The process of developing patient management plans requires a series of clinical decision-making skills that can take years in practice to develop. For the inexperienced practitioner, providing a logical, systematic patient management framework may assist in clinical scenarios and accelerate their decision-making skill development. The purpose of this study was to assess whether a novel clinical management decision aid would improve the management decision-making of chiropractic students. Methods: A prospective before and after study tracked chiropractic master degree students in their final year of study across a 10-week period from February-May, 2017. Case-based assessments were performed at baseline, after initial exposure to the decision aid, and after repeated exposure over the course of the semester. Outcome measures included the results from the 3 assessments, scored out of 20 by two markers using a standardised marking rubric, then averaged and converted to percentages; and 2 feedback questionnaires, given after initial exposure and at 10 weeks. Results: A total of 75 students (44 males; 31 females) participated in the study. The mean score at baseline was 8.34/20 (41.7%) (95% CI: 7.98, 8.70; SD: 1.56) and after initial exposure was 9.52/20 (47.6%) (95% CI: 9.06, 9.98; SD: 2.02). The mean score after repeated exposure was 15.04/20 (75.2%) (95% CI: 14.46, 15.62; SD: 2.54). From baseline to initial exposure, there was a statistically significant absolute increase in mean score of 1.18/20 (5.9%) (95% CI: 0.6, 1.76; p < 0.0001), or a 2.82/20 (14.1%) relative improvement. From baseline to repeated exposure, there was a statistically significant absolute increase in mean score of 6.7/20 (33.5%) (95% CI: 6.02, 7.38; p < 0.0001), or a 16.06/20 (80.3%) relative improvement. The questionnaire results were also favourable. 56/75 (75%) participants agreed that the decision aid was easy to use and 46/75 (61%) of participants agreed that the decision aid improved their ability to integrate various management techniques. Conclusion: Implementing a clinical management decision aid into the teaching curriculum helped to facilitate the ability of chiropractic students to develop patient management plans.

Comparative trends in coronary heart disease subgroup hospitalisation rates in England and Australia.

BACKGROUND: Population-based coronary heart disease (CHD) studies have focused on myocardial infarction (MI) with limited data on trends across the spectrum of CHD. We investigated trends in hospitalisation rates for acute and chronic CHD subgroups in England and Australia from 1996 to 2013. METHODS: CHD hospitalisations for individuals aged 35-84 years were identified from electronic hospital data from 1996 to 2013 for England and Australia and from the Oxford Region and Western Australia. CHD subgroups identified were acute coronary syndromes (ACS) (MI and unstable angina) and chronic CHD (stable angina and 'other CHD'). We calculated age-standardised and age-specific rates and estimated annual changes (95% CI) from age-adjusted Poisson regression. RESULTS: From 1996 to 2013, there were 4.9 million CHD hospitalisations in England and 2.6 million in Australia (67% men). From 1996 to 2003, there was between-country variation in the direction of trends in ACS and chronic CHD hospitalisation rates (p<0.001). During 2004-2013, reductions in ACS hospitalisation rates were greater than for chronic CHD hospitalisation rates in both countries, with the largest subgroup declines in unstable angina (England: men: -7.1 %/year, 95% CI -7.2 to -7.0; women: -7.5 %/year, 95% CI -7.7 to -7.3; Australia: men: -8.5 %/year, 95% CI -8.6 to -8.4; women: -8.6 %/year, 95% CI -8.8 to -8.4). Other CHD rates increased in individuals aged 75-84 years in both countries. Chronic CHD comprised half of all CHD admissions, with the majority involving angiography or percutaneous coronary intervention. CONCLUSIONS: Since 2004, rates of all CHD subgroups have fallen, with greater declines in acute than chronic presentations. The slower declines and high proportion of chronic CHD admissions undergoing coronary procedures requires greater focus.

Exploring the effects of transfers and readmissions on trends in population counts of hospital admissions for coronary heart disease: a Western Australian data linkage study.

OBJECTIVES: To develop a method for categorising coronary heart disease (CHD) subtype in linked data accounting for different CHD diagnoses across records, and to compare hospital admission numbers and ratios of unlinked versus linked data for each CHD subtype over time, and across age groups and sex. DESIGN: Cohort study. DATA SOURCE: Person-linked hospital administrative data covering all admissions for CHD in Western Australia from 1988 to 2013. MAIN OUTCOME: Ratios of (1) unlinked admission counts to contiguous admission (CA) counts (accounting for transfers), and (2) 28-day episode counts (accounting for transfers and readmissions) to CA counts stratified by CHD subtype, sex and age group. RESULTS: In all CHD subtypes, the ratios changed in a linear or quadratic fashion over time and the coefficients of the trend term differed across CHD subtypes. Furthermore, for many CHD subtypes the ratios also differed by age group and sex. For example, in women aged 35-54 years, the ratio of unlinked to CA counts for non-ST elevation myocardial infarction admissions in 2000 was 1.10, and this increased in a linear fashion to 1.30 in 2013, representing an annual increase of 0.0148. CONCLUSION: The use of unlinked counts in epidemiological estimates of CHD hospitalisations overestimates CHD counts. The CA and 28-day episode counts are more aligned with epidemiological studies of CHD. The degree of overestimation of counts using only unlinked counts varies in a complex manner with CHD subtype, time, sex and age group, and it is not possible to apply a simple correction factor to counts obtained from unlinked data.

Identification of myocardial infarction type from electronic hospital data in England and Australia: a comparative data linkage study.

OBJECTIVE: To determine the utility of International Classification of Diseases (ICD) codes in investigating trends in ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) using person-linked electronic hospitalisation data in England and Western Australia (WA). METHODS: All hospital admissions with myocardial infarction (MI) as the principal diagnosis were identified from 2000 to 2013 from both jurisdictions. Fourth-digit ICD-10 codes were used to delineate all MI types-STEMI, NSTEMI, unspecified and subsequent MI. The annual frequency of each MI type was calculated as a proportion of all MI admissions. For all MI and each MI type, age-standardised rates were calculated and age-adjusted Poisson regression models used to estimate annual percentage changes in rates. RESULTS: In 2000, STEMI accounted for 49% of all MI admissions in England and 59% in WA, decreasing to 35% and 25% respectively by 2013. Less than 10% of admissions were recorded as NSTEMI in England throughout the study period, whereas by 2013, 70% of admissions were NSTEMI in WA. Unspecified MI comprised 60% of all MI admissions in England by 2013, compared with <1% in WA. Trends in age-standardised rates differed for all MI (England, -2.7%/year; WA, +1.7%/year), underpinned by differing age-adjusted trends in NSTEMI (England, -6.1%/year; WA, +10.2%/year). CONCLUSION: Differences between the proportion and trends for MI types in English and WA data were observed. These were consistent with the coding standards in each country. This has important implications for using electronic hospital data for monitoring MI and identifying MI types for outcome studies.

An improved camera trap for amphibians, reptiles, small mammals, and large invertebrates.

Camera traps are valuable sampling tools commonly used to inventory and monitor wildlife communities but are challenged to reliably sample small animals. We introduce a novel active camera trap system enabling the reliable and efficient use of wildlife cameras for sampling small animals, particularly reptiles, amphibians, small mammals and large invertebrates. It surpasses the detection ability of commonly used passive infrared (PIR) cameras for this application and eliminates problems such as high rates of false triggers and high variability in detection rates among cameras and study locations. Our system, which employs a HALT trigger, is capable of coupling to digital PIR cameras and is designed for detecting small animals traversing small tunnels, narrow trails, small clearings and along walls or drift fencing.

Retrospective use of PBPK modelling to understand a clinical drug-drug interaction between dextromethorphan and GSK1034702.

1. In a clinical trial, a strong drug-drug interaction (DDI) was observed between dextromethorphan (DM, the object or victim drug) and GSK1034702 (the precipitant or perpetrator drug), following single and repeat doses. This study determined the inhibition parameters of GSK1034702 in vitro and applied PBPK modelling approaches to simulate the clinical observations and provide mechanistic hypotheses to understand the DDI. 2. In vitro assays were conducted to determine the inhibition parameters of human CYP2D6 by GSK1034702. PBPK models were populated with the in vitro parameters and DDI simulations conducted and compared to the observed data from a clinical study with DM and GSK1034702. 3. GSK1034702 was a potent direct and metabolism-dependent inhibitor of human CYP2D6, with inhibition parameters of: IC50 = 1.6 µM, Kinact = 3.7 h-1 and KI = 0.8 µM. Incorporating these data into PBPK models predicted a DDI after repeat, but not single, 5 mg doses of GSK1034702. 4. The DDI observed with repeat administration of GSK1034702 (5 mg) can be attributed to metabolism-dependent inhibition of CYP2D6. Further, in vitro data were generated and several potential mechanisms proposed to explain the interaction observed following a single dose of GSK1034702.

Is the incidence of heart attack still decreasing in Australia? Developing reliable methods for monitoring trends in myocardial infarction and coronary heart disease (AUS-MOCHA): a study protocol.

INTRODUCTION: Accurate monitoring of acute coronary heart disease (CHD) is essential for understanding the effects of primary and secondary prevention and for planning of healthcare services. The ability to reliably monitor acute CHD has been affected by new diagnostic tests for myocardial infarction (MI) and changing clinical classifications and management of CHD. Our study will develop new and reliable methods for monitoring population trends in incidence, outcomes and health service usage for acute CHD and chest pain. METHODS AND ANALYSIS: The study cohort of all CHD will be identified from the Western Australian Data Linkage System using state-wide data sets for emergency department presentation, hospitalisations and mortality data for 2002-2014. This core linked data set will be supplemented with data from hospital medical record reviews, pathology data and hospital pharmacy dispensing databases. The consistency over time of the coding of the different subgroups of CHD/chest pain (ST-elevation MI, non-ST elevation MI, unstable angina, stable angina, other CHD, non-CHD chest pain) in linked data will be assessed using these data sources, and an algorithm developed detailing groups in which temporal trends can be reliably measured. This algorithm will be used for measurement of trends in incidence and outcomes of acute CHD, and to develop further methods for monitoring acute CHD using unlinked and linked data with varying availability of hospitalisation history. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the Human Research Ethics Committees of the WA Department of Health (#2016/23) and The University of Western Australia (RA/4/1/7230). Findings will be disseminated via publication in peer-reviewed journals, and presentation at national and international conferences. There will also be a strong platform for dissemination of new monitoring methods via collaboration with the Australian Institute of Health and Welfare which will assist with promotion of these methods at state and national levels.

Secondary preventive medication use in a prevalent population-based cohort of acute coronary syndrome survivors.

AIM: Describe the dispensing patterns for guideline-recommended medications during 2008 in people with acute coronary syndrome (ACS) and how dispensing varies by gender and time since last ACS hospitalization. METHOD: A descriptive cohort spanning 20 years of people alive post-ACS in 2008. We extracted all ACS hospitalizations and deaths in Western Australia (1989-2008), and all person-linked Pharmaceutical Benefits Scheme claims nationally for 2008. Participants were 23 642 men and women (36.8%), alive and aged 65-89 years in mid-2008 who were hospitalized for ACS between 1989 and 2008. Main outcome was the proportion of the study cohort (in 2008) dispensed guideline-recommended cardiovascular medications in that year. Adjusted odds ratios estimating the association between type (and number) of guideline-recommended medications and time since last ACS hospitalization. RESULTS: Medications most commonly dispensed in 2008 were statins (79.6% of study cohort) and then angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers (ACEi/ARBs) (71.1%), aspirin or clopidogrel (59.4%), and ß-blockers (54.6%). Only 51.8% of the cohort was dispensed three or more of these drug types in 2008. Women with ACS were 18% less likely to be dispensed statins (adjusted odds ratio (OR)=0.82; 95% CI 0.76-0.88). Overall, for each incremental year since last ACS admission, there was an 8% increased odds (adjusted OR=1.08; 95% CI 1.07-1.08) of being dispensed fewer of the recommended drug regimen in 2008. CONCLUSION: Longer time since last ACS admission was associated with dispensing fewer medications types and combinations in 2008. Interventions are warranted to improve dispensing long term and any apparent gender inequality in the drug class filled.

Validation study of GRACE risk scores in indigenous and non-indigenous patients hospitalized with acute coronary syndrome.

BACKGROUND: Although cardiovascular disease is the major cause of premature death among Indigenous peoples in several advanced economies, no acute coronary syndrome (ACS) risk models have been validated in Indigenous populations. We tested the validity and calibration of three Global Registry of Acute Coronary Events (GRACE) scores among Aboriginal and non-Aboriginal Australians. METHODS: GRACE scores were calculated at admission or discharge using clinical data, with all-cause deaths obtained from data linkage. Scores for GRACE models were validated for; 1) in-hospital death, 2) death within 6 months from admission or 3) death within 6 months of discharge (this also for 1 and 5-years mortality). RESULTS: Aboriginal patient were younger (62 % aged <55 years versus 15 % non-Aboriginal) and their median GRACE scores lower than non-Aboriginal patients, as was crude mortality at 6 months from admission (6 % vs 10 %) and at 1 and 5 years. After age stratification, risk scores for Aboriginal patients were equivalent or higher, especially among those aged <55 years. There was a trend to more deaths after discharge among Aboriginal patients in each age group, suggesting an age-related under-estimation of risk. The c-statistics for the three GRACE models within both groups were between 0.75 and 0.79. CONCLUSIONS: We demonstrated for the first time that while the discriminatory capacity of GRACE risk scores among Indigenous Australians is good, the models may need re-calibrating to improve risk stratification in this and other Indigenous groups, where age of onset of coronary disease is much younger than among the original reference population.

A cohort study: temporal trends in prevalence of antecedents, comorbidities and mortality in Aboriginal and non-Aboriginal Australians with first heart failure hospitalization, 2000-2009.

BACKGROUND/OBJECTIVES: Little is known about trends in risk factors and mortality for Aboriginal Australians with heart failure (HF). This population-based study evaluated trends in prevalence of risk factors, 30-day and 1-year all-cause mortality following first HF hospitalization among Aboriginal and non-Aboriginal Western Australians in the decade 2000-2009. METHODS: Linked-health data were used to identify patients (20-84 years), with a first-ever HF hospitalization. Trends in demographics, comorbidities, interventions and risk factors were evaluated. Logistic and Cox regression models were fitted to test and compare trends over time in 30-day and 1-year mortality. RESULTS: Of 17,379 HF patients, 1,013 (5.8%) were Aboriginal. Compared with 2000-2002, the prevalence (as history) of myocardial infarction and hypertension increased more markedly in 2006-2009 in Aboriginal (versus non-Aboriginal) patients, while diabetes and chronic kidney disease remained disproportionately higher in Aboriginal patients. Risk factor trends, including the Charlson comorbidity index, increased over time in younger Aboriginal patients. Risk-adjusted 30-day mortality did not change over the decade in either group. Risk-adjusted 1-year mortality (in 30-day survivors) was non-significantly higher in Aboriginal patients in 2006-2008 compared with 2000-2002 (hazard ratio (HR) 1.44; 95% CI 0.85-2.41; p-trend = 0.47) whereas it decreased in non-Aboriginal patients (HR 0.87; 95% CI 0.78-0.97; p-trend = 0.01). CONCLUSIONS: Between 2000 and 2009, the prevalence of HF antecedents increased and remained disproportionately higher in Aboriginal (versus non-Aboriginal) HF patients. Risk-adjusted 1-year mortality did not improve in Aboriginal patients over the period in contrast with non-Aboriginal patients. These findings highlight the need for better prevention and post-HF care in Aboriginal Australians.

Life expectancy after implantation of a first cardiac permanent pacemaker (1995-2008): A population-based study.

INTRODUCTION: Research suggests that survival among the recipients of a cardiac permanent pacemaker (PPM) matches the age- and sex-matched general population in the absence of cardiovascular disease. We used linked administrative data to examine life expectancy-based outcomes for adults requiring a cardiac PPM. METHODS: Population-level hospital admissions data were used to identify all recipients of an initial PPM during 1995-2008. Expected years of additional life remaining at the time of implantation were calculated for each patient from population life tables. Observed years were calculated using linked mortality data to end 2011. Cox regression was used to determine demographic and clinical predictors of survival. RESULTS: In 8757 patients age-adjusted risk of death to 5 years was associated with male sex, higher Charlson Comorbidity Index score (excluding cardiac disease), a history of heart failure, cardiomyopathy or atrial fibrillation and emergency admission. Coronary revascularisation surgery reduced long-term risk. The observed/expected ratio of additional years of life was 0.80 for men and 0.84 for women overall, varying from 0.92 for women without significant comorbidity to 0.40 for patients with the highest Charlson score and cardiomyopathy. The oldest patients (80-99 years) did relatively well, probably reflecting patient selection. Heart disease was the most frequent cause of death. CONCLUSIONS: Life expectancy among PPM recipients without significant comorbidity approached that of the general population. Greater non-cardiac comorbidity, heart failure, atrial fibrillation and, in particular, cardiomyopathy, contributed most to the loss of expected years of life in all age groups. The oldest patients and women did relatively well.

Initial hospitalisation for atrial fibrillation in Aboriginal and non-Aboriginal populations in Western Australia.

OBJECTIVE: The epidemiology of atrial fibrillation (AF) among Aboriginal Australians is poorly described. We compared risk factors, incidence rates and mortality outcomes for first-ever hospitalised AF among Aboriginal and non-Aboriginal Western Australians 20-84 years. METHODS: This retrospective cohort study used whole-of-state person-based linked hospital and deaths data. Incident hospital AF admissions (previous AF admission-free for 15 years) were identified and subsequent mortality determined. Disease-specific comorbidity histories were ascertained by 10-year look-back. Age-standardised incidence rates were estimated and the adjusted risk of 30-day and 1-year mortality calculated using regression methods. RESULTS: Aboriginal patients accounted for 923 (2.5%) of 37 097 incident AF admissions during 2000-2009. Aboriginal patients were younger (mean age 54.8 vs 69.3 years), had lower proportions of primary field AF diagnoses and higher comorbidities than non-Aboriginal patients. The Aboriginal and non-Aboriginal age-standardised incidence rates per 100,000 for men 20-54 years were 197 and 55 (ratio=3.6), for women 20-54 years were 122 and 19 (ratio=6.4), for men 55-84 years were 1151 and 888 (ratio=1.3), and for women 55-84 years were 1050 and 571 (ratio=1.8). While 30-day mortality was similar, crude 1-year mortality risks in Aboriginal and non-Aboriginal patients were 20.6% and 16.3% (adjusted HR=1.24) and 14.4% and 9.9% in 30-day survivors (adjusted HR=1.58). CONCLUSIONS: The incidence (particularly at young ages) and long-term mortality following hospitalised AF is significantly higher in Aboriginal people. Better control of the antecedent risk factors for AF, improved detection and management of AF itself and prevention of its complications are needed.

Trends in the incidence and prevalence of cardiac pacemaker insertions in an ageing population.

OBJECTIVES: To determine contemporary population estimates of the prevalence of cardiac permanent pacemaker (PPM) insertions. METHODS: A population-based observational study using linked hospital morbidity and death registry data from Western Australia (WA) to identify all incident cases of PPM insertion for adults aged 18 years or older. Prevalence rates were calculated by age and sex for the years 1995-2009 for the WA population. RESULTS: There were 9782 PPMs inserted during 1995-2009. Prevalence rose across the study period, exceeding 1 in 50 among people aged 75 or older from 2005. This was underpinned by incidence rates which rose with age, being highest in those 85 years or older; over 500/100 000 for men throughout, and over 200/100 000 for women. Rates for patients over 75 were more than double the rates for those aged 65-74 years. Women were around 40% of cases overall. The use of dual-chamber and triple-chamber pacing increased across the study period. A cardiac resynchronisation defibrillator was implanted for 58% of patients treated with cardiac resynchronisation therapy. CONCLUSIONS: Rates of insertion and prevalence of PPM continue to rise with the ageing population in WA. As equilibrium has probably not been reached, the demand for pacing services in similarly well-developed economies is likely to continue to grow.

Disparities experienced by Aboriginal compared to non-Aboriginal metropolitan Western Australians in receiving coronary angiography following acute ischaemic heart disease: the impact of age and comorbidities.

INTRODUCTION: Aboriginal Australians have a substantially higher frequency of ischaemic heart disease (IHD) events than their non-Aboriginal counterparts, together with a higher prevalence of comorbidities. The pattern of health service provision for IHD suggests inequitable delivery of important diagnostic procedures. Published data on disparities in IHD management among Aboriginal Australians are conflicting, and the role of comorbidities has not been adequately delineated. We compared the profiles of Aboriginal and non-Aboriginal patients in the metropolitan area undergoing emergency IHD admissions at Western Australian metropolitan hospitals, and investigated the determinants of receiving coronary angiography. METHODS: Person-linked administrative hospital and mortality records were used to identify 28-day survivors of IHD emergency admission events (n =20,816) commencing at metropolitan hospitals in 2005-09. The outcome measure was receipt of angiography. The Aboriginal to non-Aboriginal risk ratio (RR) was estimated from a multivariable Poisson log-linear regression model with allowance for multiple IHD events in individuals. The subgroup of myocardial infarction (MI) events was modelled separately. RESULTS: Compared with their non-Aboriginal counterparts, Aboriginal IHD patients were younger and more likely to have comorbidities. In the age- and sex-adjusted model, Aboriginal patients were less likely than others to receive angiography (RRIHD 0.77, 95% CI 0.72-0.83; RRMI 0.81, 95% CI 0.75-0.87) but in the full multivariable model this disparity was accounted for by comorbidities as well as IHD category and MI subtype, and private health insurance (RRIHD 0.95, 95% CI 0.89-1.01; RRMI 0.94, 95% CI 0.88-1.01). When stratified by age groups, this disparity was not significant in the 25-54 year age group (RRMI 0.95, 95% CI 0.88-1.02) but was significant in the 55-84 year age group (RRMI 0.88, 95% CI 0.77-0.99). CONCLUSIONS: The disproportionate under-management of older Aboriginal IHD patients is of particular concern. Regardless of age, the disparity between Aboriginal and non-Aboriginal Australians in receiving angiography for acute IHD in a metropolitan setting is mediated substantially by comorbidities. This constellation of health problems is a 'double-whammy' for Aboriginal people, predisposing them to IHD and also adversely impacting on their receipt of angiography. Further research should investigate how older age and comorbidities influence clinical decision making in this context.

Long-term use and cost-effectiveness of secondary prevention drugs for heart disease in Western Australian seniors (WAMACH): a study protocol.

INTRODUCTION: Secondary prevention drugs for cardiac disease have been demonstrated by clinical trials to be effective in reducing future cardiovascular and mortality events (WAMACH is the Western Australian Medication Adherence and Costs in Heart disease study). Hence, most countries have adopted health policies and guidelines for the use of these drugs, and included them in government subsidised drug lists to encourage their use. However, suboptimal prescribing and non-adherence to these drugs remains a universal problem. Our study will investigate trends in dispensing patterns of drugs for secondary prevention of cardiovascular events and will also identify factors influencing these patterns. It will also assess the clinical and economic consequences of non-adherence and the cost-effectiveness of using these drugs. METHODS AND ANALYSIS: This population-based cohort study will use longitudinal data on almost 40,000 people aged 65 years or older who were hospitalised in Western Australia between 2003 and 2008 for coronary heart disease, heart failure or atrial fibrillation. Linking of several State and Federal government administrative data sets will provide person-based information on drugs dispensed precardiac and postcardiac event, reasons for hospital admission, emergency department visits, mortality and medical visits. Dispensed drug trends will be described, drug adherence measured and their association with future all-cause/cardiovascular events will be estimated. The cost-effectiveness of these long-term therapies for cardiac disease and the impact of adherence will be evaluated. ETHICS AND DISSEMINATION: Human Research Ethics Committee (HREC) approvals have been obtained from the Department of Health (Western Australian #2011/62 and Federal) and the University of Western Australia (RA/4/1/1130), in addition to HREC approvals from all participating hospitals. Findings will be published in peer-reviewed medical journals and presented at local, national and international conferences. Results will also be disseminated to consumer groups.