Background: Thirty-day risk standardized mortality rates (RSMRs) after acute myocardial infarction (AMI) are commonly used to evaluate and compare hospital performance. Patients with AMI admitted to high-performing hospitals have improved short-term mortality; however, the extent to which this early survival benefit reflects long-term survival and leads to life-time survival gains is unknown.
Methods: We analyzed data from the Cooperative Cardiovascular Project, a study of Medicare beneficiaries hospitalized for AMI with 17 years of follow-up, to compare life expectancy in patients admitted to hospitals with low and high 30-day RSMRs (calculated using previously validated methods and categorized into deciles). Cox proportional hazards regression was used to calculate life expectancy for patients in each decile. Years of life lost (YLL) per 1000 patients treated were calculated to quantify differences in life expectancy across hospital deciles.
Results: Our study sample included 119,735 patients with AMI admitted to 1,824 hospitals. Survival curves for patients in each decile separated within the first 30 days and remained parallel over 17 years of follow-up. Life expectancy estimates declined as RSMR decile increased. Patients admitted to hospitals in the lowest RSMR decile lived, on average, 6.44 (standard error (SE) 0.06) years after AMI, whereas patients in the highest RSMR decile lived 5.54 (SE 0.06) years. For every 1000 patients treated at low-performing hospitals (highest decile), 898 (SE 162) years of life were lost relative to patients treated at high-performing hospitals (lowest decile). These differences persisted after adjustment for patient characteristics and treatment. Patients in low-performing hospitals lost 1124 (SE 123) years per 1000 patients treated compared with patients in high-performing hospitals (Figure). When 30-day survivors were examined separately, there was no difference in unadjusted or adjusted life expectancy across hospital deciles.
Conclusions: Patients admitted to high-performing hospitals live longer after AMI than patients in low-performing hospitals. This survival benefit occurred in the first 30-days and persisted over the long-term, resulting in meaningful gains in life expectancy for patients admitted to high-performing hospitals.