SEVERITY MEASUREMENT METHODS AND JUDGING HOSPITAL DEATH RATES FOR PNEUMONIA

Payers and policymakers are increasingly examining hospital mortality rates as indicators of hospital quality. To be meaningful, these death rates must be adjusted for patient severity. This research examined w hether judgments about an individual hospital's risk-adjusted mortalit y is affected by the severity adjustment method. Data came from 105 ac ute care hospitals nationwide that use the Medis-Groups severity measu re. The study population was 18,016 adults hospitalized in 1991 for pn eumonia. Multivariable logistic models to predict in-hospital death we re computed separately for 14 severity methods, controlling for patien t age, sex, and diagnosis-related group (DRG). For each hospital, obse rved-to-expected death rates and z scores were calculated for each sev erity method. The overall in-hospital death rate was 9.6%. Unadjusted mortality rates for the 105 hospitals ranged from 1.4% to 19.6%. After adjusting for age, sex, DRG, and severity, 73 facilities had observed mortality rates that did not differ significantly from expected rates according to all 14 severity methods; two had rates significantly hig her than expected for all 14 severity methods. For 30 hospitals, obser ved mortality rates differed significantly from expected rates when ju dged by one or more but not all 14 severity methods. Kappa analysis sh owed fair to excellent agreement between severity methods. The 14 seve rity methods agreed about relative hospital performance more often tha n expected by chance, but perceptions of individual hospitals' mortali ty rates varied using different severity adjustment methods for almost one third of facilities. Judgments about individual hospital performa nce using different severity adjustment approaches may reach different conclusions.