The effects of case mix on hospital costs and revenues for medicare patients in California.

Hospital competition and managed care have negatively affected hospital profitability. In the current turbulent health care environment in the U.S., hospitals in California have argued that the rate of increase in hospital costs is faster than the rate of increase in hospital revenues. By employing Medicare case mix indexes (CMIs) as a primary policy variable, this study found that the coefficients for CMIs in hospital costs for Medicare patients were smaller than those in hospital revenues in the years of 1986, 1989 and 1998. However, the coefficients for CMIs in hospital costs for Medicare patients were greater than those in hospital revenues in the years of 1992 and 1995. Although there were some differences between the coefficients for CMIs in hospital costs and revenues for Medicare patients, those differences found to be statistically insignificant. In spite of claims on behalf of Californian hospitals, the rate of increase in hospital costs for Medicare patients had not been greater than that of hospital revenues for Medicare patients.