Objectives Recent studies in acute coronary syndrome (ACS) have reported mixed results for trends in ACS subtypes. The All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) 31 study evaluated trends in ACS event rates, invasive management and mortality of ST-elevation myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable angina (UA) in New Zealand.
Methods All ACS hospitalisations between 2006 and 2016 were identified from routinely collected national data and categorised into STEMI, NSTEMI, UA and MI unspecified (MIU). Annual hospitalisation, coronary procedure, 28-day and 1-year mortality rates were calculated and trends tested using Poisson regression adjusting for age and sex.
Results Over the 11-year study period, there were 188 264 ACS admissions, of which 16.0% were STEMI, 54.5% NSTEMI, 25.7% UA and 3.8% MIU. Event rates of all ACS subtypes fell: STEMI by 3.4%/year, NSTEMI by 5.9%/year and UA by 8.5%/year, while the proportion of patients with ACS receiving angiography and revascularisation increased by 5.6% per year. Rates of percutaneous coronary intervention rose for STEMI, NSTEMI and UA, but coronary artery bypass grafting increased only for NSTEMI and UA. Mortality at 28 days and 1 year was higher for STEMI than NSTEMI and lowest for UA. There was a relative 1.6%/year decline in 1 year mortality for NSTEMI (p<0.001), but no significant change for STEMI and UA.
Conclusions We observed declines in the event rates of all ACS subtypes and increases in revascularisation rates. The finding that mortality declined in patients with NSTEMI, but not in patients with STEMI and UA, despite increases in invasive procedures, requires further investigation.
- coronary artery disease
- acute coronary syndromes
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Contributors All authors were involved in the planning, data acquisition, analysis, interpretation, writing and reviewing of the work pertaining to this manuscript.
Funding This research was supported by grants from the New Zealand Health Research Council (grant no 11/800). Researchers are independent from funders, and the funders had no role in the study design,collection, analysis or interpretation of data. ANZACS-QI programme implementation, coordination and analysis: Programme implementation is coordinated by the National Institute for Health Innovation (NIHI) at the University of Auckland. The ANZACS-QI programme is funded by the NZ Ministry of Health. ANZACS-QI Governance group: Andrew Kerr (chair), Chris Nunn, Dean Boddington, Gary Sutcliffe, Gerry Devlin, Harvey White, John Edmond, Jonathon Tisch, Sue Riddle, Kim Marshall, Mayanna Lund, Michael Williams (deputy chair), Nick Fisher and Tony Scott.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information.
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