Clinical Factors and Therapeutic Strategies With Improvements in Survival After NSTEMI
What is the impact of changes in patients’ baseline clinical risk and use of guideline-indicated treatments for management of non–ST-segment elevation myocardial infarction (NSTEMI) on clinical outcomes?
Data on patients with NSTEMI in 247 hospitals in England and Wales were obtained from the Myocardial Ischemia National Audit Project between January 1, 2003, and June 30, 2013 (final follow-up, December 31, 2013). Baseline demographics, clinical risk (GRACE risk score), and pharmacological and invasive coronary treatment data were collected. The main outcome measure was the adjusted all-cause 180-day post-discharge mortality time trends estimated using flexible parametric survival modeling.
Among 389,057 patients with NSTEMI (median age, 72.7 years [interquartile range, 61.7-81.2 years]; 63.1% men), there were 113,586 deaths (29.2%). From 2003-2004 to 2012-2013, proportions with intermediate to high GRACE risk decreased (87.2% vs. 82.0%); proportions with lowest risk increased (4.2% vs. 7.6%; p = 0.01 for trend). The prevalence of diabetes, hypertension, cerebrovascular disease, chronic obstructive pulmonary disease, chronic renal failure, previous invasive coronary strategy, and current or ex-smoking status increased (all p < 0.001). Unadjusted all-cause mortality rates at 180 days decreased from 10.8% to 7.6% (unadjusted hazard ratio [HR], 0.968 [95% CI, 0.966-0.971]; difference in absolute mortality rate [AMR] per 100 patients [AMR/100], −1.81 [95% CI, −1.95 to −1.67]). These findings were not substantially changed when adjusted additively by baseline GRACE risk score (HR, 0.975 [95% CI, 0.972-0.977]; AMR/100, −0.18 [95% CI, −0.21 to −0.16]), sex and socioeconomic status (HR, 0.975 [95% CI, 0.973-0.978]; difference in AMR/100, −0.24 [95% CI, −0.27 to −0.21]), comorbidities (HR, 0.973 [95% CI, 0.970-0.976]; difference in AMR/100, −0.44 [95% CI, −0.49 to −0.39]), and pharmacological therapies (HR, 0.972 [95% CI, 0.964-0.980]; difference in AMR/100, −0.53 [95% CI, −0.70 to −0.36]). However, the direction of association was reversed after further adjustment for use of an invasive coronary strategy (HR, 1.02 [95% CI, 1.01-1.03]; difference in AMR/100, 0.59 [95% CI, 0.33-0.86]), which was associated with a relative decrease in mortality of 46.1% (95% CI, 38.9%-52.0%).
The authors concluded that improvements in all-cause mortality in NSTEMI were significantly associated with use of an invasive coronary strategy and not entirely related to a decline in baseline clinical risk or increased use of pharmacological therapies.
This study reports that improvements in survival following NSTEMI were primarily associated with use of an invasive coronary strategy. The temporal reduction in baseline acute coronary syndrome risk, increase in comorbidities, and use of guideline-directed therapies did not fully explain the relative 3.2% yearly improvement in survival. These data suggest that outcomes can be improved by incorporating proven therapies into practice and we need to make concerted efforts to translate the success of evidence-based therapies to low- and middle-income countries, where it is most needed.
Keywords: Acute Coronary Syndrome, Coronary Artery Disease, Cerebrovascular Disorders, Diabetes Mellitus, Hypertension, Kidney Failure, Chronic, Myocardial Infarction, Myocardial Ischemia, Outcome Assessment (Health Care), Pulmonary Disease, Chronic Obstructive, Secondary Prevention, Smoking, Risk, ESC Congress
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