Trends in cardiovascular outcomes after acute coronary syndrome in New Zealand 2006-2016

Objectives: Characterisation of trends in acute coronary syndrome (ACS) outcomes are critical to informing clinical practice and quality improvement, but there are few recent population studies for ACS. We reviewed the recent trends in the outcomes of ACS in New Zealand (NZ).

Methods: All patients with ACS admitted to NZ public hospitals in 2006-2016 were identified from hospital discharge records, and their first ACS hospitalisations per year extracted for analysis. Thirty-day and 1-year death, myocardial infarction, stroke, heart failure and bleeding rates were calculated for each calendar year. Trends in outcome rates were assessed using generalised linear mixed models.

Results: Total annual ACS hospitalisations decreased from 685 to 424 per 100 000. Using first patient hospitalisations per year (n=1 55 060), we found significant annual declines in all major outcomes except for non-cardiovascular deaths. All-cause mortality fell from 10.5% to 9.1% at 30 days (adjusted OR 0.985 per year change, p<0.001) and from 21.8% to 18.7% at 1 year (OR=0.994, p=0.016). This was related to significant decreases in cardiovascular death at both time points (OR=0.982 and 0.987, respectively, p<0.001), outweighing a slight increase in non-cardiovascular death at 1 year (OR=1.009, p=0.014). One-year rates of myocardial infarction, heart failure, stroke and bleeding rates all decreased significantly over time.

Conclusion: ACS outcomes including all-cause mortality, cardiovascular death, myocardial infarction, stroke, heart failure and bleeding at 30 days and 1 year improved over the last decade in NZ, reflecting successful implementation and advances in prevention, medical and invasive management in ACS over time.