Long-term cardiovascular outcomes in patients hospitalised with acute coronary syndrome subtypes in Western Australia, 2002–2019

Background Despite advances in acute coronary syndrome (ACS) management, contemporary data assessing long-term prognosis after ST-segment elevation myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable angina (UA) are scarce. Methods Linked hospitalisation and mortality data identified all 30-day survivors of index STEMI, NSTEMI and UA hospitalisation in Western Australia between 2002 and 2019. We assessed the cumulative 5-year incidence of major adverse cardiovascular events (MACE), comprising non-fatal MI, stroke, heart failure hospitalisation or cardiovascular death and separately all-cause death in 30-day survivors of index ACS hospitalisation. Associations were examined using Cox proportional hazards modelling after adjustment for potential confounders. Results The cohort totalled 73 321 patients with ACS, 65% males, 22.3% with STEMI, 43.2% NSTEMI and 34.6% UA with mean age 63.2, 68.8 and 66.4 years, respectively. Patients with NSTEMI and UA compared with STEMI were more likely to be female with additional comorbidities. Cumulative 5-year MACE rates after NSTEMI were 29.7% vs 19.4% and 19.9% after STEMI and UA, respectively (log-rank p<0.001), while all-cause mortality was 29.8% vs 15.9% and 17.2%, respectively (log-rank p<0.001). There was no temporal improvement in multivariable-adjusted risk of outcomes for all ACS subtypes throughout the study period. The adjusted HRs for MACE and all-cause death were 1.5-fold or higher in males and females with STEMI or NSTEMI versus UA. Conclusions Long-term risk of MACE and all-cause death remains high and unchanged among 30-day survivors of all ACS subtypes in the recent era. Long-term surveillance and optimal secondary prevention are important in survivors of all ACS subtypes.