Cardiovascular Risk Factors and Secondary Events Among Acute and Chronic Stable Myocardial Infarction Patients: Findings from a Managed Care Database

INTRODUCTION: Long-term risk for recurrent cardiovascular events among myocardial infarction (MI) patients in the acute versus chronic stable phase is not well characterized. This study was conducted to evaluate risk factors associated with all-cause mortality and cardiovascular (CVD) morbidity and to determine the transition period from the acute to chronic stable phase of disease. METHODS: Administrative claims data from a managed care database (2007-2012) were linked to the Social Security Death Index. Kaplan-Meier curves were generated over a 3-year period. The association between risk factors and clinical endpoints was assessed using Cox proportional hazard models. Poisson models estimated the 'transition time' from acute to chronic phase of disease. RESULTS: On average, recurrent cardiovascular event rates were higher among acute MI patients in comparison to the chronic MI patients during the first 3 months of follow-up. Over the 3-year follow-up period, survival curves became parallel and for some outcomes (i.e., acute myocardial infarction and bleeding events), were not statistically significantly different between the two groups. In both the acute and chronic MI cohorts, diabetes, heart failure, and renal disease were consistently statistically significant and positively associated with greater risk of death and ischemic events. PAD was consistently associated with increased risk among the chronic cohort and composite endpoints among the acute patients. CONCLUSIONS: Greater understanding of differences in the CVD risk profiles and the transition from acute to chronic stable phase may help identify high-risk patients and inform clinical risk stratification and long-term disease management in MI patients. FUNDING: Merck & Co., Inc., Kenilworth, NJ, USA.