Associations among hospital capacity, utilization, and mortality of US medicare beneficiaries, controlling for sociodemographic factors

Objective. To explore whether geographic variations in Medicare hospital ut ilization rates are due to differences in local hospital capacity, after co ntrolling for socioeconomic status and disease burden, and to determine whe ther greater hospital capacity is associated with lower Medicare mortality rates. Data Sources/Study Setting. The study population: a 20 percent sample of 19 89 Medicare enrollees. Measures of resources were based on a national small area analysis of 313 Hospital Referral Regions (HRR). Demographic and soci oeconomic data were obtained from the 1990U.S. Census. Measures of local di sease burden were developed using Medicare claims files. Study Design. The study was a cross-sectional analysis of the relationship between per capita measures of hospital resources in each region and hospit al utilization and mortality rates among Medicare enrollees. Regression tec hniques were used to control for differences in sociodemographic characteri stics and disease burden across areas. Data Collection/Extraction Methods. Data on the study population were obtai ned from Medicare enrollment (Denominator File) and hospital claims files ( MedPAR) and U.S. Census files. Principal Findings. The per capita supply of hospital beds varied by more t han twofold across U.S. regions. Residents of areas with more beds were up to 30 percent more likely to be hospitalized, controlling for ecologic meas ures of socioeconomic characteristics and disease burden. A greater proport ion of the population was hospitalized at least once during the year in are as with more beds; death was also more likely to take place in an inpatient setting. All effects were consistent across racial and income groups. Resi dence in areas with greater levels of hospital resources was not associated with a decreased risk of death. Conclusions. Residence in areas of greater hospital capacity is associated with substantially increased use of the hospital, even after controlling fo r socioeconomic characteristics and illness burden. This increased use prov ides no detectable mortality benefit.