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.

Rationale and design of a randomized controlled trial of pneumococcal polysaccharide vaccine for prevention of cardiovascular events: The Australian Study for the Prevention through Immunization of Cardiovascular Events (AUSPICE).

BACKGROUND: Research has shown that vaccination with Streptococcus pneumoniae reduced the extent of atherosclerosis in experimental animal models. It is thought that phosphorylcholine lipid antigens in the S. pneumoniae cell wall induce the production of antibodies that cross-react with oxidized low-density lipoprotein, a component of atherosclerotic plaques. These antibodies may bind to and facilitate the regression of the plaques. Available data provide evidence that similar mechanisms also occur in humans, leading to the possibility that pneumococcal vaccination protects against atherosclerosis. A systematic review and meta-analysis, including 8 observational human studies, of adult pneumococcal polysaccharide vaccination for preventing cardiovascular disease in people older than 65 years, showed a 17% reduction in the odds (odds ratio 0.83, 95% CI 0.71-0.97) of having an acute coronary syndrome event. METHODS/DESIGN: The AUSPICE is a multicenter, randomized, placebo-controlled, double-blind, clinical trial to formally test whether vaccination with the pneumococcal polysaccharide vaccine protects against cardiovascular events (fatal and nonfatal acute coronary syndromes and ischemic strokes). Cardiovascular outcomes will be obtained during 4 to 5 years of follow-up, through health record linkage with state and national administrative data sets. CONCLUSION: This is the first registered randomized controlled trial (on US, World Health Organization, Australia and New Zealand trial registries) to be conducted to test whether vaccination with the pneumococcal polysaccharide vaccine will reduce cardiovascular events. If successful, vaccination can be readily extended to at-risk groups to reduce the risk of cardiovascular diseases.

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.

Should fee-for-service be for all guideline-advocated acute coronary syndrome (ACS) care? Observations from the Snapshot ACS study.

OBJECTIVE: The aim of the present study was to explore the association of health insurance status on the provision of guideline-advocated acute coronary syndrome (ACS) care in Australia. METHODS: Consecutive hospitalisations of suspected ACS from 14 to 27 May 2012 enrolled in the Snapshot study of Australian and New Zealand patients were evaluated. Descriptive and logistic regression analysis was performed to evaluate the association of patient risk and insurance status with the receipt of care. RESULTS: In all, 3391 patients with suspected ACS from 247 hospitals (23 private) were enrolled in the present study. One-third of patients declared private insurance coverage; of these, 27.9% (304/1088) presented to private facilities. Compared with public patients, privately insured patients were more likely to undergo in-patient echocardiography and receive early angiography; furthermore, in those with a discharge diagnosis of ACS, there was a higher rate of revascularisation (P < 0.001). Each of these attracts potential fee-for-service. In contrast, proportionately fewer privately insured ACS patients were discharged on selected guideline therapies and were referred to a secondary prevention program (P = 0.056), neither of which directly attracts a fee. Typically, as GRACE (the Global Registry of Acute Coronary Events) risk score rose, so did the level of ACS care; however, propensity-adjusted analyses showed lower in-hospital adverse events among the insured group (odds ratio 0.68; 95% confidence interval 0.52-0.88; P = 0.004). CONCLUSION: Fee-for-service reimbursement may explain differences in the provision of selected guideline-advocated components of ACS care between privately insured and public patients.

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.

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.

Trends from 1996 to 2007 in incidence and mortality outcomes of heart failure after acute myocardial infarction: a population-based study of 20,812 patients with first acute myocardial infarction in Western Australia.

BACKGROUND: Advances in treatment for acute myocardial infarction (AMI) are likely to have had a beneficial impact on the incidence of and deaths attributable to heart failure (HF) complicating AMI, although limited data are available to support this contention. METHODS AND RESULTS: Western Australian linked administrative health data were used to identify 20 812 consecutive patients, aged 40 to 84 years, without prior HF hospitalized with an index (first) AMI between 1996 and 2007. We assessed the temporal incidence of and adjusted odds ratio/hazard ratio for death associated with HF concurrent with AMI admission and within 1 year after discharge. Concurrent HF comprised 75% of incident HF cases. Between the periods 1996-1998 and 2005-2007, the prevalence of HF after AMI declined from 28.1% to 16.5%, with an adjusted odds ratio of 0.50 (95% CI, 0.44 to 0.55). The crude 28-day case-fatality rate for patients with concurrent HF declined marginally from 20.5% to 15.9% (P < 0.05) compared with those without concurrent HF, in whom the case-fatality rate declined from 11.0% to 4.8% (P < 0.001). Concurrent HF was associated with a multivariate-adjusted odds ratio of 2.2 for 28-day mortality and a hazard ratio of 2.2 for 1-year mortality in 28-day survivors. Occurrence of HF within 90 days of the index AMI was associated with an adjusted hazard ratio of 2.7 for 1-year mortality in 90-day survivors. CONCLUSIONS: Despite encouraging declines in the incidence of HF complicating AMI, it remains a common problem with high mortality. Increased attention to these high-risk patients is needed given the lack of improvement in their long-term prognosis.

Impact of the introduction of drug eluting stents on clinical outcomes in patients undergoing percutaneous and surgical coronary artery revascularisation procedures in Western Australia.

BACKGROUND: Increasing rates of percutaneous coronary intervention (PCI) and decreasing rates of coronary artery bypass graft (CABG) surgery followed the introduction of drug eluting stents in Western Australia in 2002. We assessed the impact of these changes on one-year outcomes for the total population of patients undergoing coronary artery revascularisation procedures (CARP) in Western Australia between 2000-2004. METHODS: Clinical and linked administrative data (inpatient admissions and death) were merged for all patients who had their first CARP with stent or CABG in Western Australia between 2000-2004. The clinical data were collected from all hospitals in Western Australia where CARP procedures are performed. We calculated the unadjusted (Kaplan-Meier) and adjusted (Cox) risks for one-year death (all-cause), death (all-cause) or admission for myocardial infarction (MI), target vessel revascularisation (TVR) and the composite outcome of death/MI/TVR (major adverse cardiac events, MACE). RESULTS: Over the study period, there were 14,118 index CARPs. The use of drug eluting stents increased from 0% to 95.8% of PCI procedures, and PCI procedures increased from 61.1% to 74.4% of all CARPS. There were no temporal changes in adjusted one-year mortality or death/MI. Overall, adjusted one-year MACE fell from 11.3% in 2000 to 8.5% in 2004 (p<0.0001) due to a significant reduction in TVR in the PCI group. CONCLUSION: The introduction of drug eluting stents and resulting changes in coronary revascularisation strategies were not associated with changes in the one-year risk of major clinical endpoints (death or death/MI), but were associated with a significant reduction in the risk of MACE, driven entirely by a reduction in TVR after PCI. This real world study supports the effectiveness of drug eluting stents in reducing repeat procedures in the total CARP population without increasing the risk of death or MI.

Downward trend in the prevalence of hospitalisation for atherothrombotic disease.

BACKGROUND: The prevalence of hospitalised atherothrombotic disease affecting the coronary, cerebrovascular and peripheral vasculature is expected to increase due to improving survival, ageing and changing risk factor profiles. This study determined sex, age-standardised and age-specific (35-54, 55-69, 70-84years) prevalence of atherothrombotic disease and its association with diabetes and chronic kidney disease in Western Australian residents from 2000 to 2007. METHODS: In a cross-sectional and longitudinal study, person-linked hospitalisations for atherothrombotic disease were obtained using records from 1985. From 2000 to 2007, total and vasculature-specific prevalence of atherothrombotic disease (as a principal diagnosis) was calculated using a 15-year lead-in to determine prior disease and comorbidity. RESULTS: In 2007, 45,916 (8.6%) men and 22,782 (4.3%) women in Western Australia had established atherothrombotic disease and about 25% had diabetes, 10% had chronic kidney disease, and 5% had both. From 2000 to 2007 the estimated average annual change in age-standardised atherothrombotic disease prevalence was -0.6%/year (95% CI -0.8, -0.4) in men and -0.7%/year (95% CI -1.0, -0.4) in women. Similar modest declines were seen in age-standardised prevalence of monovascular and polyvascular atherothrombotic disease. The proportion of cases with diabetes increased by about 5%/year, the proportion having chronic kidney disease increased slowly in women (1.5%/year) and was stable in men, and the proportion with both comorbidities increased at about 9%/year. CONCLUSION: The age-standardised prevalence of atherothrombotic disease requiring hospitalisation has been in marginal decline in Western Australia this decade, despite the proportion of affected persons with diabetes and/or chronic kidney disease steadily rising.

Temporal trends in the incidence and recurrence of hospitalised atherothrombotic disease in an Australian population, 2000-07: data linkage study.

OBJECTIVES: To examine temporal trends in the incidence and recurrence of hospitalised coronary heart disease (CHD), cerebrovascular disease (CeVD) and peripheral arterial disease (PAD) separately and combined, and by the history of all forms of atherothrombotic disease (ATD). DESIGN: Population-based longitudinal data linkage study. SETTING: Western Australia. PARTICIPANTS: All patients aged 35-84 years hospitalised in Western Australia for CHD, CeVD or PAD from 2000 to 2007. MAIN OUTCOME MEASURES: Age-standardised incidence and recurrence rates of CHD, CeVD and PAD stratified by ATD history, sex and age. RESULTS: 107 576 events (65.9% men) were identified; 70% of all admissions were for CHD. In patients without a history of any ATD, incidence rates declined significantly in all groups, although the reduction in incident CHD in women was marginal (-0.7%/year, 95% CI -1.5 to +0.1%). The largest annual reductions in incidence rates were for PAD (men, -6.4%/year, 95% CI -7.7 to -5.0%; women, -5.4%/year, 95% CI -7.2 to -3.6%) and CeVD in women (-4.0%/year, 95% CI -5.0 to -3.0%). Falls in overall recurrence rates were greatest for CeVD (men, -3.2%/year, 95% CI -4.7 to -1.6%; women -4.6%/year, 95% CI -6.4 to -2.7%). Trends across all categories of polyvascular ATD were generally downward, although not all changes were statistically significant. CONCLUSION: The incidence and recurrence rates of hospitalised ATD have decreased over time, including in patients with disease involving multiple vascular territories. This implies that primary and secondary prevention strategies have been broadly effective. However, high absolute rates of recurrence and limited reduction in 35-54-year-old individuals highlight patient groups to target to reduce further the burden of ATD.

Screening Education And Recognition in Community pHarmacies of Atrial Fibrillation to prevent stroke in an ambulant population aged >=65 years (SEARCH-AF stroke prevention study): a cross-sectional study protocol.

BACKGROUND: Atrial fibrillation (AF) is associated with a high risk of stroke and may often be asymptomatic. AF is commonly undiagnosed until patients present with sequelae, such as heart failure and stroke. Stroke secondary to AF is highly preventable with the use of appropriate thromboprophylaxis. Therefore, early identification and appropriate evidence-based management of AF could lead to subsequent stroke prevention. This study aims to determine the feasibility and impact of a community pharmacy-based screening programme focused on identifying undiagnosed AF in people aged 65 years and older. METHODS AND ANALYSIS: This cross-sectional study of community-based screening to identify undiagnosed AF will evaluate the feasibility of screening for AF using a pulse palpation and handheld single-lead electrocardiograph (ECG) device. 10 community pharmacies will be recruited and trained to implement the screening protocol, targeting a total of 1000 participants. The primary outcome is the proportion of people newly identified with AF at the completion of the screening programme. Secondary outcomes include level of agreement between the pharmacist's and the cardiologist's interpretation of the single-lead ECG; level of agreement between irregular rhythm identified with pulse palpation and with the single-lead ECG. Process outcomes related to sustainability of the screening programme beyond the trial setting, pharmacist knowledge of AF and rate of uptake of referral to full ECG evaluation and cardiology review will also be collected. ETHICS AND DISSEMINATION: Primary ethics approval was received on 26 March 2012 from Sydney Local Health District Human Research Ethics Committee-Concord Repatriation General Hospital zone. Results will be disseminated via forums including, but not limited to, peer-reviewed publication and presentation at national and international conferences. CLINICAL TRIALS REGISTRATION NUMBER: ACTRN12612000406808.