Abstract
AIMS: To investigate whether improved survival from non-ST-elevation myocardial infarction (NSTEMI), according to GRACE risk score, was associated with guideline-indicated treatments and diagnostics, and persisted after hospital discharge. METHODS AND RESULTS: National cohort study (n = 389 507 patients, n = 232 hospitals, MINAP registry), 2003-2013. The primary outcome was adjusted all-cause survival estimated using flexible parametric survival modelling with time-varying covariates. Optimal care was defined as the receipt of all eligible treatments and was inversely related to risk status (defined by the GRACE risk score): 25.6% in low, 18.6% in intermediate, and 11.5% in high-risk NSTEMI. At 30 days, the use of optimal care was associated with improved survival among high [adjusted hazard ratio (aHR) -0.66 95% confidence interval (CI) 0.53-0.86, difference in absolute mortality rate (AMR) per 100 patients (AMR/100-0.19 95% CI -0.29 to -0.08)], and intermediate (aHR = 0.74, 95% CI 0.62-0.92; AMR/100 = -0.15, 95% CI -0.23 to -0.08) risk NSTEMI. At the end of follow-up (8.4 years, median 2.3 years), the significant association between the use of all eligible guideline-indicated treatments and improved survival remained only for high-risk NSTEMI (aHR = 0.66, 95% CI 0.50-0.96; AMR/100 = -0.03, 95% CI -0.06 to -0.01). For low-risk NSTEMI, there was no association between the use of optimal care and improved survival at 30 days (aHR = 0.92, 95% CI 0.69-1.38) and at 8.4 years (aHR = 0.71, 95% CI 0.39-3.74). CONCLUSION: Optimal use of guideline-indicated care for NSTEMI was associated with greater survival gains with increasing GRACE risk, but its use decreased with increasing GRACE risk.