Association of changes in clinical characteristics and management with improvement in survival among patients with ST-elevation myocardial infarction

Abstract

Context: The contemporary decline in mortality reported in patients with ST-segment elevation myocardial infarction (STEMI) has been attributed mainly to improved use of reperfusion therapy.

Objective: To determine potential factors-beyond reperfusion therapy-associated with improved survival in patients with STEMI over a 15-year period.

Design, setting, and patients: Four 1-month French nationwide registries, conducted 5 years apart (between 1995, 2000, 2005, 2010), including a total of 6707 STEMI patients admitted to intensive care or coronary care units.

Main outcome measures: Changes over time in crude 30-day mortality, and mortality standardized to the 2010 population characteristics.

Results: Mean (SD) age decreased from 66.2 (14.0) to 63.3 (14.5) years, with a concomitant decline in history of cardiovascular events and comorbidities. The proportion of younger patients increased, particularly in women younger than 60 years (from 11.8% to 25.5%), in whom prevalence of current smoking (37.3% to 73.1%) and obesity (17.6% to 27.1%) increased. Time from symptom onset to hospital admission decreased, with a shorter time from onset to first call, and broader use of mobile intensive care units. Reperfusion therapy increased from 49.4% to 74.7%, driven by primary percutaneous coronary intervention (11.9% to 60.8%). Early use of recommended medications increased, particularly low-molecular-weight heparins and statins. Crude 30-day mortality decreased from 13.7% (95% CI, 12.0-15.4) to 4.4% (95% CI, 3.5-5.4), whereas standardized mortality decreased from 11.3% (95% CI, 9.5-13.2) to 4.4% (95% CI, 3.5-5.4). Multivariable analysis showed a consistent reduction in mortality from 1995 to 2010 after controlling for clinical characteristics in addition to the initial population risk score and use of reperfusion therapy, with odds mortality ratios of 0.39 (95%, 0.29-0.53, P <.001) in 2010 compared with 1995.

Conclusion: In France, the overall rate of cardiovascular mortality among patients with STEMI decreased from 1995 to 2010, accompanied by an increase in the proportion of women younger than 60 years with STEMI, changes in other population characteristics, and greater use of reperfusion therapy and recommended medications.