Measures of hospital competition and their impact on early mortality for congestive heart failure, acute myocardial infarction and cardiac surgery

Objective: To measure competition amongst providers and to examine whether a correlation exists with hospitals mortality for congestive heart failure (CHF), acute myocardial infarction (AMI), isolated-coronary artery bypass graft (CABG) or valve surgery. Design: Cross-sectional study based on publically available data from the National Outcome Evaluation Program (Edition 2016) of the Italian Agency for Regional Health Services. Setting and participants: Patients discharged during 2015 for CHF or AMI, and between 2014 and 2015 for cardiac surgery (respectively, from 662, 395 and 91 hospitals). Main outcome measures: Risk-adjusted mortality rates at 30 days and measures of hospital competition for areas centred on hospital' location (fixed-radius 50-150 km, variable-radius to capture 10-30 hospitals and 6-10% of national volume). Competition was estimated as number of providers and Herfindahl-Hirschman Index (HHI). Results: Indicators of competitions varied by condition and were sensitive to method used for the area definition. Hospital mortality after AMI and valve surgery increased with competition in areas identified by the variable-radius method (higher rates for a greater number of hospitals or lower HHIs). In area with fixed radius of 100-150 km, competition reduced mortality after CABG procedures (lower rates for a greater number of hospitals or smaller HHIs). Neither the number of hospitals nor HHI correlated with outcomes in CHF. Conclusions: The measures of hospital competition changed according to definition of local market and results in mortality correlations varied among conditions. Understanding the relationship between hospital competition and outcomes is important to identify strategies to improve quality of care.