Lee Nedkoff

Age- and Sex-Specific Trends in the Incidence of Hospitalized Acute Coronary Syndromes in Western Australia

Background— The incidence of myocardial infarction has declined during the past 4 decades in many populations. However, there are limited population data measuring trends in acute coronary syndromes (ACS). We therefore examined temporal trends in the incidence of hospitalized ACS by age and sex in a population-based cohort. Methods and Results— The Western Australian Data Linkage System, a repository of linked administrative health data, was used to identify 29 421 incident ACS hospitalizations between 1996 and 2007. Poisson log-linear regression models were used to calculate incidence rate changes. Age-standardized incidence rates of ACS declined annually in men by 1.7% (95% confidence interval [CI], −2.1 to −1.3) and in women by 1.6% (95% CI, −2.1 to −1.0). These declining rates were underpinned by annual reductions in the incidence of unstable angina (men, −3.0%; 95% CI, −3.7 to −2.4; women, −2.5; 95% CI, −3.3 to −1.7), whereas annual changes in myocardial infarction incidence were less (men, −1.0%; 95% CI, −1.5 to −0.5; women, −0.8%; 95% CI, −1.6 to 0). However, the overall trends masked age group differences, with ACS incidence increasing annually in 35- to 54-year-old women (2.3%; 95% CI, 1.0 to 3.8), predominantly driven by increasing incidence of myocardial infarction. Conclusions— The age-standardized incidence of ACS decreased significantly in Western Australia from 1996 to 2007. However, an increase in ACS incidence in women ages 35 to 54 years is troubling and warrants further investigation.

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.

Discordant age and sex-specific trends in the incidence of a first coronary heart disease event in Western Australia from 1996 to 2007

Objective To determine age- and sex-specific population trends in fatal and non-fatal first coronary heart disease (CHD) events in Western Australia from 1996 to 2007. Design Longitudinal retrospective population study. Setting State-wide population. Patients All residents aged 35–84 years during 1996–2007 who died or were hospitalised with a principal diagnosis of acute CHD. Data sources Person-linked file of mortality and morbidity records. Main outcome measures Age-standardised (35–84 years) and age-specific (35–54, 55–69, 70–84 years) rates by gender for a first CHD event were calculated with a 10-year lead-in period to define first events. Results From 1996 to 2007 there were 36 631 first CHD events, including 8518 (23%) fatal cases in those aged 35–84 years. Overall, age-adjusted rates for fatal first CHD declined 5.3%/year in men (95% CI −6.1% to −4.6%) and 6.5%/year in women (95% CI −7.5% to −5.5%). However, age-specific fatal first CHD rates were neutral in both men aged 35–54 years (0.1%/year; 95% CI −1.8% to 2.1%) and women of the same age, (−1.6%/year; 95% CI −5.6% to 2.5%). Age-specific trends in non-fatal CHD rates reflected the same trends in fatal CHD events in men and women, with rates reportedly increasing in women aged 35–54 years (2.5%/year (95% CI 1.1% to 3.9%). Conclusion The age-specific decline in fatal and non-fatal first CHD rates in older men and women was not observed in those aged 35–54 years. These novel findings provide evidence for a levelling in the CHD incidence rates in younger adults and puts renewed importance on primary prevention in this group.

Temporal trends in initial and recurrent lower extremity amputations in people with and without diabetes in Western Australia from 2000 to 2010

AIMS To examine temporal trends in lower extremity amputations in people with type 1 diabetes, type 2 diabetes and cardiovascular disease (CVD) without diabetes in Western Australia (WA) from 2000 to 2010. METHODS We used linked health data to identify all non-traumatic lower extremity amputations in adults aged ≥20 years with diabetes and/or CVD from 2000 to 2010 in WA. Annual age- and sex-standardised rates of total, initial and recurrent amputations, stratified by major and minor status, were calculated for type 1 and type 2 diabetes, and CVD without diabetes, from the at-risk population for each group. Age- and sex-adjusted trends were estimated from Poisson regression models. RESULTS 5891 lower extremity amputations were identified. Peripheral vascular disease (71%), hypertension (70%) and chronic kidney disease (60%) were highly prevalent. Average annual rates of total amputations were 724, 564 and 66 per 100,000 person-years in type 1, type 2 diabetes and CVD without diabetes respectively. Rates of initial amputations fell significantly by 2.4%/year (95% CI -3.5, -1.4) in type 2 diabetes, with similar declines for type 1 diabetes and CVD without diabetes (interaction p=0.96), driven by large falls in major amputations. There was limited improvement in recurrence rates overall, with recurrent minor amputations increasing significantly in type 2 diabetes (+3.5%/year, 95% CI +1.3%, +5.7%). CONCLUSION Lower extremity amputation rates have declined at a population level in people with diabetes and CVD without diabetes, suggesting improvements in prevention and management for this high-risk patient group, however limited declines in recurrent amputations requires further investigation.

Trends in incidence and prevalence of hospitalization for atrial fibrillation and associated mortality in Western Australia, 1995-2010

OBJECTIVE Hospitalization for atrial fibrillation (AF) is a large and growing public health problem. We examined current trends in the incidence, prevalence, and associated mortality of first-ever hospitalization for AF. METHODS Linked hospital admission data were used to identify all Western Australia residents aged 35-84 years with prevalent AF and incident (first-ever) hospitalization for AF as a principal or secondary diagnosis during 1995-2010. RESULTS There were 57,552 incident hospitalizations, mean age 69.8 years, with 41.4% women. Over the calendar periods, age- and sex-standardized incidence of hospitalization for AF as any diagnosis declined annually by 1.1% (95% CI; 0.93, 1.29), while incident AF as a principal diagnosis increased annually by 1.2% (95% CI; 0.84, 1.50). Incident AF hospitalization was higher among men than women, and 15-fold higher in the 75-84 compared with 35-64 year age group. The age- and sex-standardized prevalence of AF increased annually by 2.0% (95% CI; 1.88, 2.03) over the same period. Comorbidity trends were mixed with diabetes and valvular heart disease increasing, and hypertension, coronary artery disease, heart failure, cerebrovascular disease, and chronic kidney disease decreasing. The 1-year all-cause mortality after incident AF hospitalization declined from 17.6% to 14.6% (trend P<0.001), with an adjusted hazard ratio of 0.86 (95% CI; 0.81, 0.91). CONCLUSION This contemporary study shows that incident AF hospitalization is not increasing except for AF as a principal diagnosis, while population prevalence of hospitalized AF has risen substantially. The high 1-year mortality following incident AF hospitalization has improved only modestly over the recent period.

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.

Comparative Trends in the Incidence of Hospitalized Myocardial Infarction and Coronary Heart Disease in Adults With and Without Diabetes Mellitus in Western Australia From 1998 to 2010

Background—The risk of myocardial infarction (MI) is elevated in people with diabetes mellitus (DM) compared with non-DM counterparts. The aim of this study was to compare population trends in the incidence of hospitalized MI and coronary heart disease (CHD) in adults with and without DM. Methods and Results—All incident hospitalized MI and CHD events were identified from whole-population hospital data in Western Australia for 1998 to 2010. Annual age-standardized MI and CHD incidence rates were calculated for people with and without DM aged 35 to 84 years and age-adjusted trends estimated from Poisson regression. There were 26 610 incident MI and 56 142 incident CHD cases during the study period. MI incidence rates fell in men (−2.9%/y; 95% confidence interval [CI], −3.7 to −2.1) and women (−3.8%/y; 95% CI, −4.8 to −2.1) with DM, representing overall reductions of 35% and 43% respectively, with comparable reductions in incident CHD. Downward trends in MI incidence in those with DM were most apparent in 55- to 84-year olds. In adults without DM, there was no decline in MI incidence but a small significant decrease in incident CHD (men, −1.5%/y; 95% CI, −1.8 to −1.2 and women, −1.3%/y; 95% CI, −1.8 to −0.9). Incidence rate ratios for MI in men with versus without DM declined from 4.5 (95% CI, 4.2–4.8) to 3.1 (95% CI, 2.9–3.3) and from 6.0 (95% CI, 5.4–6.6) to 3.8 (95% CI, 3.5–4.1) in women between 1998 and 2010. Conclusions—There have been significant reductions in incidence rates of MI and CHD in adults with DM between 1998 and 2010; however, the excess risk of MI incidence remains 3 to 4× greater in people with DM.

Projected age- and sex-specific prevalence of cardiovascular diseases in Western Australian adults from 2005-2045

Background For decades, the incidence and mortality of cardiovascular diseases (CVDs) have declined. More recently, we have seen a halting in these declines, especially at younger ages. It is difficult to predict how these changing trends will impact CVD prevalence. We aimed to predict future prevalence of CVDs in Western Australian adults from 2005–2045 based on current incidence and mortality probabilities, population growth and ageing. Methods and results Multi-state life table models were developed using 2005–2009 age- and sex-specific incidence and mortality probabilities from the Western Australian Data Linkage System. Prevalence of CVD, coronary heart disease (CHD) and stroke was projected until 2045. Life expectancy and lifetime risk were estimated. We estimate that compared to 2005–2009, we will see 37,235 (CVD), 23,129 (CHD) and 9806 (stroke) more incident cases in 2040–2044. The prevalence of total CVD is predicted to increase from 8.4% in men and 5.1% in women in 2005 to 12.7% and 7.9% respectively in 2045. This seems to be mainly due to population growth and ageing, with some effect of changing incidence and mortality. In Western Australia this represents an additional 106,949 adults living with CVD, of which 65,951 with CHD and 10,928 with stroke, in 2045 compared to 2005. Conclusions Assuming no major changes in prevention and treatment of CVD, the prevalence will likely increase, with consequent increases in health care need and cost. These findings need to be confirmed by studies in which prevalence is consistently and empirically measured and monitored over time.

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.

Temporal Trends in Sudden Cardiac Death From 1997 to 2010: A Data Linkage Study

BACKGROUND Community-wide trends data for sudden cardiac death (SCD) are scarce, unlike widely reported declines in cardiovascular disease (CVD) mortality. Using administrative data, we aimed to examine population-level trends in SCD, stratified by sex, age and prior CVD hospitalisation. METHODS Person-linked mortality and hospital morbidity data were used to identify SCD and determine hospitalisation and comorbidity using a 10-year hospitalisation lookback period. Log-linear Poisson regression was used to calculate annual rate changes and rate ratios. RESULTS In Western Australia, 7160 SCD cases were identified from 1997 to 2010 with males comprising 69%. Overall age-standardised SCD rates decreased by 17% in men and 31% in women from 1997-2001 to 2007-2010. The annual rate reduction was higher in women than men (-4.0%/year versus -2.3%/year; p=0.0039). Significant reductions were observed for 55-69 year-old and 70-84 year-old men and women but not for the 35-54 year-olds. The overall relative risk comparing men to women increased slightly from 2.4 in 1997 to 3.0 in 2010 (trend p=0.0039) but differed across age groups. The relative risk declined in 35-54 year-olds from 5.1 to 3.2 whereas it increased from 2.9 to 3.9 in 55-69 year-olds and 1.9 to 2.3 in 70-84 year-olds. Declining trends in SCD rates were observed in those with and without prior CVD and were similar to CVD mortality trends (-4.9%/year in men and -5.5%/year in women). CONCLUSIONS Trends in rates of SCD fell in middle to older aged men and women, with and without CVD, and mirrored the fall in fatal CVD. Limited improvement in 35-54 year-olds requires further investigation.