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

Lost Therapeutic Benefit of Delayed Low-Density Lipoprotein Cholesterol Control in Statin-Treated Patients and Cost-Effectiveness Analysis of Lipid-Lowering Intensification

OBJECTIVES

Attainment of low-density lipoprotein cholesterol (LDL-C) therapeutic goals in statin-treated patients remains suboptimal. We quantified the health economic impact of delayed lipid-lowering intensification from an Australian healthcare and societal perspective.

METHODS

A lifetime Markov cohort model (n = 1000) estimating the impact on coronary heart disease (CHD) of intensifying lipid-lowering treatment in statin-treated patients with uncontrolled LDL-C, at moderate to high risk of CHD with no delay or after a 5-year delay, compared with standard of care (no intensification), starting at age 40 years. Intensification was tested with high-intensity statins or statins + ezetimibe. LDL-C levels were extracted from a primary care cohort. CHD risk was estimated using the pooled cohort equation. The effect of cumulative exposure to LDL-C on CHD risk was derived from Mendelian randomization data. Outcomes included CHD events, quality-adjusted life-years (QALYs), healthcare and productivity costs, and incremental cost-effectiveness ratios (ICERs). All outcomes were discounted annually by 5%.

RESULTS

Over the lifetime horizon, compared with standard of care, achieving LDL-C control with no delay with high-intensity statins prevented 29 CHD events and yielded 30 extra QALYs (ICERs AU$13 205/QALY) versus 22 CHD events and 16 QALYs (ICER AU$20 270/QALY) with a 5-year delay. For statins + ezetimibe, no delay prevented 53 CHD events and gave 45 extra QALYs (ICER AU$37 271/QALY) versus 40 CHD events and 29 QALYs (ICER of AU$44 218/QALY) after a 5-year delay.

CONCLUSIONS

Delaying attainment of LDL-C goals translates into lost therapeutic benefit and a waste of resources. Urgent policies are needed to improve LDL-C goal attainment in statin-treated patients.

Population genomic screening of young adults for familial hypercholesterolaemia: a cost-effectiveness analysis

AIMS

The aim of this study was to assess the impact and cost-effectiveness of offering population genomic screening to all young adults in Australia to detect heterozygous familial hypercholesterolaemia (FH).

METHODS AND RESULTS

We designed a decision analytic Markov model to compare the current standard of care for heterozygous FH diagnosis in Australia (opportunistic cholesterol screening and genetic cascade testing) with the alternate strategy of population genomic screening of adults aged 18-40 years to detect pathogenic variants in the LDLR/APOB/PCSK9 genes. We used a validated cost-adaptation method to adapt findings to eight high-income countries. The model captured coronary heart disease (CHD) morbidity/mortality over a lifetime horizon, from healthcare and societal perspectives. Risk of CHD, treatment effects, prevalence, and healthcare costs were estimated from published studies. Outcomes included quality-adjusted life years (QALYs), costs and incremental cost-effectiveness ratio (ICER), discounted 5% annually. Sensitivity analyses were undertaken to explore the impact of key input parameters on the robustness of the model. Over the lifetime of the population (4 167 768 men; 4 129 961 women), the model estimated a gain of 33 488years of life lived and 51 790 QALYs due to CHD prevention. Population genomic screening for FH would be cost-effective from a healthcare perspective if the per-test cost was ≤AU$250, yielding an ICER of <AU$28 000 per QALY gained. From a societal perspective, population genomic screening would be cost-saving. ICERs from societal perspective remained cost-saving after adaptation to other countries.

CONCLUSION

Based on our model, offering population genomic screening to all young adults for FH could be cost-effective, at testing costs that are feasible.

Comparative Clinical Effectiveness of Population-Based Atrial Fibrillation Screening Using Contemporary Modalities: A Decision-Analytic Model

Background Atrial fibrillation (AF) screening is endorsed by certain guidelines for individuals aged ≥65 years. Yet many AF screening strategies exist, including the use of wrist-worn wearable devices, and their comparative effectiveness is not well-understood. Methods and Results We developed a decision-analytic model simulating 50 million individuals with an age, sex, and comorbidity profile matching the United States population aged ≥65 years (ie, with a guideline-based AF screening indication). We modeled no screening, in addition to 45 distinct AF screening strategies (comprising different modalities and screening intervals), each initiated at a clinical encounter. The primary effectiveness measure was quality-adjusted life-years, with incident stroke and major bleeding as secondary measures. We defined continuous or nearly continuous modalities as those capable of monitoring beyond a single time-point (eg, patch monitor), and discrete modalities as those capable of only instantaneous AF detection (eg, 12-lead ECG). In total, 10 AF screening strategies were effective compared with no screening (300-1500 quality-adjusted life-years gained/100 000 individuals screened). Nine (90%) effective strategies involved use of a continuous or nearly continuous modality such as patch monitor or wrist-worn wearable device, whereas 1 (10%) relied on discrete modalities alone. Effective strategies reduced stroke incidence (number needed to screen to prevent a stroke: 3087-4445) but increased major bleeding (number needed to screen to cause a major bleed: 1815-4049) and intracranial hemorrhage (number needed to screen to cause intracranial hemorrhage: 7693-16 950). The test specificity was a highly influential model parameter on screening effectiveness. Conclusions When modeled from a clinician-directed perspective, the comparative effectiveness of population-based AF screening varies substantially upon the specific strategy used. Future screening interventions and guidelines should consider the relative effectiveness of specific AF screening strategies.

Queensland Cardiovascular Data Linkage (QCard): A population-based cohort study

Queensland is Australia's hotspot for cardiovascular disease (CVD). Critically, beyond modifiable lifestyle risk factors; socio-demographic differences and environmental factors account for significant variations in healthcare use and outcomes among cardiac patients across the country. To better understand the impacts of these factors on the health of cardiac patients, there is a need for a comprehensive and robust longitudinal cohort study that can unpack the underlying dynamics. This paper describes the protocol for the Queensland Cardiovascular Linkage (QCard) Study. The QCard is a longitudinal linkage cohort study of cardiac patients who were first hospitalised with any cardiac condition in 2010, with follow up hospitalisations until December 2015. The primary aim of the QCard is to identify and characterise the nature and impact of socio-demographic inequality among those presenting for the first time with the most common form of CVD in Australia (heart disease) in Queensland from 2010 with minimum 5-years follow-up of subsequent healthcare utilisation and outcomes. A secondary aim is to undertake an exploration of the impact of environmental and specific health service factors on healthcare use and survival time in the same QCard cohort. Administrative public and private hospital inpatient, outpatient and emergency department data for all of Queensland will be linked with individual primary care data and pharmaceutical data. These data will also be linked to regional socio-demographic data and environmental data, as well as data that describes the features of each hospital in the region. The findings from the study will provide critical information for cardiac patients, clinicians and health policymakers. Such information ranges from identifying most vulnerable cardiac patients who may require targeted needs to providing estimates for cost-effective ways of evaluating healthcare interventions that seek to improve the health of cardiac patients.

Low rates of immediate coronary angiography among young adults resuscitated from sudden cardiac arrest

AIM

Coronary artery disease (CAD) has recently been emphasized as a major cause of sudden cardiac arrest (SCA) in young adults. We aim to assess the rate of immediate coronary angiography performance in young patients resuscitated from SCA.

METHODS

From May 2011 to May 2017, all cases of out-of-hospital SCA aged 18-40 years alive at hospital admission were prospectively included in 48 hospitals of the Great Paris area. Cardiovascular causes of SCA were centrally adjudicated, and management including immediate coronary angiography performance was assessed.

RESULTS

Out of 3579 SCA admitted alive, 409 (11.4%) patients were under 40 years of age (32.3 ± 6.2 years, 69.7% males), with 244 patients having a definite cause identified. Among those, CAD accounted for 72 (29.5%) cases, of which 64 (88.9%) were acute coronary syndromes. The rate of immediate coronary angiography was only 41.7% compared to 65.1% among those ≥40-years (P < 0.001). During the study period, while the rate of immediate coronary angiography increased from 60.5% to 70.3% (P < 0.001) in patients aged ≥40 years, the rate in patients aged less than 40 years remained stable (43.5% to 45.3%, P = 0.795). Patients younger than 40 years were significantly less likely to undergo immediate coronary angiography (OR = 0.34, 95% CI: 0.25-0.47), although early angiography was associated with survival at hospital discharge (OR = 2.68, 95% CI: 1.21-6.00).

CONCLUSION

CAD is the first cause of SCA in young adults aged less than 40 years. The observed low rates of immediate coronary angiography suggest a missed opportunity for early intervention.

Decade Long Trends (2001-2011) in the Incidence Rates of Initial Acute Myocardial Infarction

Despite the magnitude and impact of acute coronary disease, there are limited population-based data in the United States describing relatively recent trends in the incidence rates of acute myocardial infarction (AMI). The objectives of this study were to describe decade long (2001-2011) trends in the incidence rates of initial hospitalized episodes of AMI, with further stratification of these rates by age, sex, and type of AMI, in residents of central Massachusetts hospitalized at 11 area medical centers. The study population consisted of 3,737 adults hospitalized with a first AMI at 11 medical centers in central Massachusetts on a biennial basis between 2001 and 2011. The median age of this study population was 70 years, 57% were men, and 90% were white. Patients hospitalized during the most recent study years (2009/11) were younger, more likely to be men, have more co-morbidities, and less in-hospital complications as compared with those in the earliest study years (2001/03). The overall age-adjusted hospital incidence rates (per 100,000 persons) of initial AMI declined (from 319 to 163), for men (from 422 to 219), women (from 232 to 120), for patients with a ST segment elevation (129 to 56), and for those with an non-ST segment elevation (190 to 107) between 2001 and 2011, respectively. In conclusion, the incidence rates of initial AMI declined appreciably in residents of central Massachusetts who were hospitalized with AMI during the years under study.

Trends in age- and sex-specific prevalence and incidence of cardiovascular disease in Western Australia

Background Temporal trends in incidence and mortality of cardiovascular disease (CVD) have been well described, with recent data suggesting declining improvements in those aged under 55 years. However, little is known about the combined impact of incidence and mortality trends on disease prevalence, an important indicator of disease burden and cost. We analysed changes in age-specific and age-standardised temporal trends in prevalence and incidence of CVD subtypes. Methods Annual prevalence and incidence rates of coronary heart disease, cerebrovascular disease and peripheral arterial disease for the Western Australian population for 1995-2010 were calculated using data from the Western Australian Data Linkage System. Joinpoint regression analyses were used to identify joinpoints in trends in age-specific and age-standardised annual prevalence and incidence rates for each CVD subtype. Results Between 1995 and 2010, age- and sex-specific incidence and prevalence of the CVD subtypes generally decreased among middle-aged and older adults, but were stable or increased among younger adults. In < 55 year olds, increases in incidence tended to occur from 2003, while increases in prevalence were from 2007/2008. Declines in age-standardised incidence were greater than those in crude incidence, with changes in population structure having a greater impact among men than women. Conclusions The majority of CVDs occurs in older adults. Our findings of generally worsening trends in prevalence in younger adults across most CVD subtypes were in contrast to generally declining trends in older age groups. These data highlight the importance of monitoring prevalence and incidence, particularly in younger adults.

European Society of Cardiology: Cardiovascular Disease Statistics 2017

Aims

The European Society of Cardiology (ESC) Atlas has been compiled by the European Heart Agency to document cardiovascular disease (CVD) statistics of the 56 ESC member countries. A major aim of this 2017 data presentation has been to compare high-income and middle-income ESC member countries to identify inequalities in disease burden, outcomes, and service provision.

Methods and results

The Atlas utilizes a variety of data sources, including the World Health Organization, the Institute for Health Metrics and Evaluation, and the World Bank to document risk factors, prevalence, and mortality of cardiovascular disease and national economic indicators. It also includes novel ESC-sponsored survey data of health infrastructure and cardiovascular service provision provided by the national societies of the ESC member countries. Data presentation is descriptive with no attempt to attach statistical significance to differences observed in stratified analyses. Important differences were identified between the high-income and middle-income member countries of the ESC with regard to CVD risk factors, disease incidence, and mortality. For both women and men, the age-standardized prevalence of hypertension was lower in high-income countries (18% and 27%) compared with middle-income countries (24% and 30%). Smoking prevalence in men (not women) was also lower (26% vs. 41%) and together these inequalities are likely to have contributed to the higher CVD mortality in middle-income countries. Declines in CVD mortality have seen cancer becoming a more common cause of death in a number of high-income member countries, but in middle-income countries declines in CVD mortality have been less consistent where CVD remains the leading cause of death. Inequalities in CVD mortality are emphasized by the smaller contribution they make to potential years of life lost in high-income countries compared with middle-income countries both for women (13% vs. 23%) and men (20% vs. 27%). The downward mortality trends for CVD may, however, be threatened by the emerging obesity epidemic that is seeing rates of diabetes increasing across all the ESC member countries. Survey data from the National Cardiac Societies showed that rates of cardiac catheterization and coronary artery bypass surgery, as well as the number of specialist centres required to deliver them, were greatest in the high-income member countries of the ESC. The Atlas confirmed that these ESC member countries, where the facilities for the contemporary treatment of coronary disease were best developed, were often those in which declines in coronary mortality have been most pronounced. Economic resources were not the only driver for delivery of equitable cardiovascular health care, as some middle-income ESC member countries reported rates for interventional procedures and device implantations that matched or exceeded the rates in wealthier member countries.

Conclusion

In documenting national CVD statistics, the Atlas provides valuable insights into the inequalities in risk factors, health care delivery, and outcomes of CVD across the ESC member countries. The availability of these data will underpin the ESC's ambitious mission 'to reduce the burden of cardiovascular disease' not only in its member countries but also in nation states around the world.

The changing epidemiology of myocardial infarction in Olmsted County, Minnesota, 1995-2012

BACKGROUND

Contemporary data on the epidemiology of myocardial infarction in the population are limited and derived primarily from cohorts of hospitalized myocardial infarction patients. We assessed temporal trends in incident and recurrent myocardial infarction, with further partitioning of the rates into prehospital deaths and hospitalized events, in a geographically defined community.

METHODS

All myocardial infarction events recorded among Olmsted County, Minnesota residents aged 25 years and older from 1995-2012, including prehospital deaths, were classified into incident and recurrent. Standardized rates were calculated and temporal trends compared.

RESULTS

Altogether, 5258 myocardial infarctions occurred, including 1448 (27.5%) recurrences; 430 (8.2%) prehospital deaths were recorded. Among hospitalized events, recurrent myocardial infarction was associated with greater mortality risk than incident myocardial infarction (age-, sex-, and year-adjusted hazard ratio, 1.49; 95% confidence interval, 1.37-1.61). Although the overall rate of myocardial infarction declined over time (average annual percent change, -3.3), the magnitude of the decline varied widely. Incident hospitalized myocardial infarction rate fell 2.7%/y, compared with decreases of 1.5%/y in recurrent hospitalized myocardial infarction, 14.1%/y in prehospital fatal incident myocardial infarction, and 12.3%/y in prehospital fatal recurrent myocardial infarction (all P for diverging trends < .05). These trends resulted in an increasing proportion of recurrences among hospitalized myocardial infarctions (25.3% in 1995-2000, 26.8% in 2001-2006, and 29.0% in 2007-2012, Ptrend = .02).

CONCLUSIONS

Over the past 18 years, a heterogeneous decline in myocardial infarction rates occurred in Olmsted County, resulting in transitions from incident to recurrent events and from prehospital deaths to hospitalized myocardial infarctions. Recurrent myocardial infarction confers a worse prognosis, thereby stressing the need to optimize prevention strategies in the population.

National trends in main causes of hospitalization: a multi-cohort register study of the finnish working-age population, 1976-2010

Background

The health transition theory argues that societal changes produce proportional changes in causes of disability and death. The aim of this study was to identify long-term changes in main causes of hospitalization in working-age population within a nation that has experienced considerable societal change.

Methodology

National trends in all-cause hospitalization and hospitalizations for the five main diagnostic categories were investigated in the data obtained from the Finnish Hospital Discharge Register. The seven-cohort sample covered the period from 1976 to 2010 and consisted of 3,769,356 randomly selected Finnish residents, each cohort representing 25% sample of population aged 18 to 64 years.

Principal Findings

Over the period of 35 years, the risk of hospitalization for cardiovascular diseases and respiratory diseases decreased. Hospitalization for musculoskeletal diseases increased whereas mental and behavioral hospitalizations slightly decreased. The risk of cancer hospitalization decreased marginally in men, whereas in women an upward trend was observed.

Conclusions/Significance

A considerable health transition related to hospitalizations and a shift in the utilization of health care services of working-age men and women took place in Finland between 1976 and 2010.

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.

Shifts in the age distribution and from acute to chronic coronary heart disease hospitalizations

BACKGROUND

Shifts in the burden of coronary heart disease (CHD) from an acute to chronic illness have important public health consequences.

OBJECTIVE

To assess age-sex-specific time trends in rates and characteristics of acute and chronic forms of CHD hospital admissions in the Netherlands.

METHODS

Using nationwide Dutch registers, we assessed time trends between 1998 and 2007 in hospitalization rates of 188,266 acute myocardial infarction (AMI, ICD-9 410), 294,374 unstable angina (ICD-9 411, 413) and 205,649 chronic forms of CHD (ICD-9 412, 414) admissions.

RESULTS

Between 1998 and 2007, the age-standardized CHD hospitalization rate declined from 688 to 545 per 100,000 in men and from 281 to 229 per 100,000 in women. Overall, hospitalization rates decreased at younger age (<75 years) but increased in very old age (≥85 years). The annual percentage change in hospitalization rates was larger for AMI (men:-5.1%, women:-4.4%) than for unstable angina patients (men:-2.0%, women:-2.0%). For chronic CHD, the average annual percentage change was +0.7% in men and +2.1% in women. The proportion of chronic CHD in the total of CHD admissions increased between 1998 and 2007 from 29% to 36% in men and from 23% to 30% in women. The proportion of AMI decreased from 30% to 24% in men and from 27% to 22% in women.

CONCLUSIONS

An increasing proportion of Dutch CHD hospital admissions was for chronic forms of CHD. The age at hospitalization was pushed towards older age: premature CHD admission declined over time and admission rates at very old age increased.

Effect of cardiovascular prevention strategies on incident coronary disease hospitalisation rates in Spain; an ecological time series analysis

OBJECTIVE

To assess the overall population impact of primary prevention strategies (promotion of healthy lifestyles, prevention of smoking and use of vascular risk drug therapy) of coronary disease in Spain.

DESIGN

Ecological time series analysis, 1982-2009.

SETTING

All public and private hospitals in Spain.

PARTICIPANTS

General population.

OUTCOME

Incident coronary disease hospitalisation as derived from official hospital discharge data.

METHODS

Annual hospitalisation rates were modelled according to nationwide use of statins, antihypertensive, antidiabetic and antiplatelet drugs, and prevalences of smoking, obesity and overweight. Additive generalised models and mixed Poisson regression models were used for the purpose, taking year as the random-effect variable and adjusting for age, sex, prevalence of vascular risk factors and the number of hospital beds in intensive and coronary care units.

RESULTS

Across 28 years and 671.5 million person-years of observation, there were 2 986 834 hospitalisations due to coronary disease; of these, 1 441 980 (48.28%) were classified as incident. Hospitalisation rates increased from 1982 to 1996, with an inflection point in 1997 and a subsequent 52% decrease until 2009. Prevalences of smoking, obesity, overweight and use of vascular risk drug therapy were significantly associated with hospitalisation rates (p<0.001): incidence rates ratios (95% CI) for the fourth versus the first quartile were 1.46 (1.42 to 1.50), 1.80 (1.78 to 1.83), 1.58 (1.55 to 1.60) and 0.57 (0.51 to 0.63), respectively. These variables accounted for 92% of interannual variability.

CONCLUSIONS

After decades of continuous rises, hospitalisation due to incident ischaemic heart disease has been cut by half, an achievement associated with the decline in smoking and the increase in vascular risk drug therapy. These results indicate that these two primary prevention strategies have been effective at a population level, thanks to an appropriate balance between financial and health goals, something that should be left intact despite the current economic crisis. Future strategies ought to lay special stress on excessive body weight prevention.

Continuing decrease in coronary heart disease mortality in Sweden

Background

Deaths from coronary heart disease (CHD) have been decreasing in most Western countries over the last few decades. In contrast, a flattening of the decrease in mortality has been recently reported among younger age groups in some countries. We aimed to determine whether the decrease in CHD mortality is flattening among Swedish young adults.

Methods

We examined trends in CHD mortality in Sweden between 1987 and 2009 among persons aged 35 to 84 years using CHD mortality data from the Swedish National Register on Cause of Death. Annual percent changes in rates were examined using Joinpoint software.

Results

Overall, CHD mortality rates decreased by 67.4% in men and 65.1% in women. Among men aged 35–54 years, there was a modest early attenuation from a marked initial decrease. In the oldest women aged 75–84 years, an attenuation in the mortality decrease was observed from 1989 to 1992, followed by a decrease, as in all other age groups.

Conclusions

In Sweden, coronary heart disease deaths are still falling. We were unable to confirm a flattening of the decline in young people. Death rates continue to decline in men and women across all age groups, albeit at a slower pace in younger men since 1991. Continued careful monitoring of CHD mortality trends in Sweden is required, particularly among young adults.

Population trends and inequalities in incidence and short-term outcome of acute myocardial infarction between 1998 and 2007

OBJECTIVE

We studied time trends in acute myocardial infarction (AMI) incidence, including out-of-hospital mortality proportions and hospitalized case-fatality rates. In addition, we compared AMI trends by age, gender and socioeconomic status.

METHODS

We linked the national Dutch hospital discharge register with the cause of death register to identify first AMI in patients ≥ 35 years between 1998 and 2007. Events were categorized in three groups: 178,322 hospitalized non-fatal, 43,210 hospitalized fatal within 28 days, and 75,520 out-of-hospital fatal AMI events. Time trends were analyzed using Joinpoint and Poisson regression.

RESULTS

Since 1998, age-standardized AMI incidence rates decreased from 620 to 380 per 100,000 in 2007 in men and from 323 to 210 per 100,000 in 2007 in women. Out-of-hospital mortality decreased from 24.3% of AMI in 1998 to 20.6% in 2007 in men and from 33.0% to 28.9% in women. Hospitalized case-fatality declined from 2003 onwards. The annual percentage change in incidence was larger in men than women (-4.9% vs. -4.2%, P<0.001). Furthermore, the decline in AMI incidence was smaller in young (35-54 years: -3.8%) and very old (≥ 85 years: -2.6%) men and women compared to middle-aged individuals (55-84 years: -5.3%, P<0.001). Smaller declines in AMI rates were observed in deprived socioeconomic quintiles Q5 and Q4 relative to the most affluent quintile Q1 (P=0.002 and P=0.015).

CONCLUSIONS

Substantial improvements were observed in incidence, out-of-hospital mortality and short-term case-fatality after AMI in the Netherlands. Young and female groups tend to fall behind, and socioeconomic inequalities in AMI incidence persisted and have not narrowed.

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.