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@NEJM Ask the Authors & Experts: Life Expectancy after Myocardial Infarction by Hospital Performance

Original Article

Life Expectancy after Myocardial Infarction by Hospital Performance


Emily M. Bucholz, M.D., Ph.D., M.P.H.,1 Neel M. Butala, M.D., M.B.A.,2 Shuangge Ma, Ph.D.,3 Sharon-Lise T. Normand, Ph.D.,4 Harlan M. Krumholz, M.D., S.M.5


1 Department of Medicine, Boston Children’s Hospital, Boston, MA 2 Department of Internal Medicine, Massachusetts General Hospital, Boston, MA 3 Department of Biostatistics, Yale School of Public Health, New Haven, CT 4 Department of Health Care Policy, Harvard Medical School and Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 5 Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven CT; Robert Wood Johnson Clinical Scholars Program, Department of Medicine; Center for Outcomes Research and Evaluation, Yale-New Haven Hospital, New Haven, CT


Thirty-day risk-standardized mortality rates after acute myocardial infarction are commonly used to evaluate and compare hospital performance. However, it is not known whether differences between hospitals in early patient survival are associated with differences in long-term survival.

We analyzed data from the Cooperative Cardiovascular Project, a study of Medicare beneficiaries hospitalized for acute myocardial infarction between 1994-96 with 17 years of follow-up. We grouped hospitals into five strata based on case-mix severity. Within each case- mix stratum, we compared life expectancy in patients admitted to high and low-performing hospitals, as defined by quintiles of thirty-day risk-standardized mortality rates. Cox proportional hazards models were used to calculate life expectancy.

The study sample included 119,735 patients with acute myocardial infarction admitted to 1,824 hospitals. Within each case-mix stratum, survival curves for patients admitted to hospitals in each risk-standardized mortality rate quintile separated within the first 30 days and then remained parallel over 17 years of follow-up. Estimated life expectancy declined as hospital risk-standardized mortality rate quintile increased. On average, patients treated at high- performing hospitals lived between 1.14 and 0.84 years longer than patients treated at low- performing hospitals, depending on hospital case-mix. When 30-day survivors were examined separately, there was no difference in unadjusted or adjusted life expectancy across hospital risk-standardized mortality rate quintiles.

Patients admitted to high-performing hospitals after acute myocardial infarction had longer life expectancies than patients treated in low-performing hospitals. This survival benefit arose in the first 30 days and persisted over the long term.

Appeared in The New England Journal of Medicine on September 28, 2016 at 5:00 PM.

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