Greater use of certain cardiovascular drugs linked to decline in mortality after MI

Long-term improvement following myocardial infarction (MI) among older patients can be attributed to increased use of cardiovascular (CV) drugs, said Soko Setoguchi, MD, DrPh.

She used medical claims data from New Jersey and Pennsylvania to identify 21,848 Medicare patients hospitalized for MI from 1995 to 2004 who survived for at least 30 days following discharge. Within 30 days after discharge, she assessed whether these patients filled prescriptions for statins, beta blockers, ACE inhibitors/angiotensin receptor blockers (ARBs), and antiplatelet agents.

Regression models were used to estimate trends in long-term mortality. Indicators for CV drug use and MI-related procedures were then sequentially introduced into the regression model to assess whether cardiovascular drug use could explain trends of long-term survival over the decade of observation.

During an average of 3.5 years (74,892 person-years) of follow-up, 12,142 patients died. During the observation period, there was a trend a greater prevalence of comorbidities, such as hypertension, peripheral vascular disease, cerebrovascular disease, diabetes, and chronic kidney disease. Use of percutaneous coronary interventions increased over time. Use of each drug examined also increased over time.

After adjusting for comorbidities and demographic variables, mortality after MI decreased significantly by 3% per year from 1995 to 2004.

When adjusting for statin use, beta blockers, ACE inhibitors/ARBs, and antiplatelet drugs, the association between time trend and mortality was entirely eliminated. In contrast, adjusting for increased use of MI-related procedures, but not for the study drugs, diminished the time trend slightly, but did not eliminate the effect.

"These findings suggest that change in survival may be primarily attributable to increased use of recommended drugs," said Dr. Setoguchi, epidemiologist and physician from the division of pharmacoepidemiology, Brigham and Women's Hospital and Harvard Medical School, Boston.