Health System Characteristics and Rates of Readmission After Acute Myocardial Infarction in the United States

BACKGROUND Interventions to reduce early readmissions have focused on patient characteristics and the importance of early follow-up; however, less is known about the characteristics of health systems, including quality, capacity, and intensity, and their influence on readmission rates in the United States. Therefore, we examined the association of hospital patterns of medical care with rates of 30-day readmission. METHODS AND RESULTS Medicare beneficiaries hospitalized for an AMI (n=188 611) between 2008 and 2009 in 1088 hospitals in the United States were included in our cohort. We tested the association between hospital patterns of medical care quality (discharge planning care quality), capacity (hospital size measured as the number of beds, hospital-level Medicare all medical admission rates, supply of primary care physicians and cardiologists), and intensity (measures of care during the last 6 months of life) on CMS risk-adjusted rates of 30-day readmission using Poisson multilevel mixed-effects models adjusting for patient- and hospital-level covariates. There were 38 350 readmissions at 30-days (20.3%) AMI discharges. Controlling for patient characteristics, measures of hospital care associated with higher rates of readmission included higher hospital-level rates for all medical admissions, per capita primary care physicians and cardiologists, and last 6 months of life care intensity measures including increased number of hospital days, number of ICU days, number of physician visits, and 10 or more different physicians seen during the last 6 months of life. Better discharge quality and larger hospitals were associated with lower rates of readmission. CONCLUSIONS In addition to quality of care, high 30-day readmission rates are associated with hospital-level measures of capacity and intensity. Efforts to reduce readmission rates may need to address these broader patterns of medical care.