The effect of hospital experience on mortality among patients hospitalized with acquired immunodeficiency syndrome in California

BACKGROUND: Several studies in the 1980s suggested that mortality rates for patients hospitalized with the acquired immunodeficiency syndrome (AIDS) were lower in hospitals that cared for greater numbers of AIDS patients. We sought to determine whether this observation persisted in the mid-1990s in California. SUBJECTS AND METHODS: We performed an analysis of hospital discharge data for 7,901 adults discharged with human immunodeficiency virus (HIV) or AIDS-related diagnoses from all acute care hospitals (n = 333) in California during 1994. The main outcome measure was in-hospital mortality, adjusted for severity of illness, comorbidity, prior hospitalizations, and other patient and hospital characteristics. RESULTS: Among 7,901 persons hospitalized with AIDS, the unadjusted inpatient mortality was 9.0%. The adjusted mortality rate varied significantly (P<0.0001) from 12.4% among institutions with the lowest quartile of AIDS experience to 10.3%, 6.3%, and 7.6% by quartile of greater AIDS experience. Increasing severity of illness, comorbidity, and previous hospitalizations were also significant predictors of increased mortality. Sex, race, and insurance status were not associated with hospital mortality. CONCLUSIONS: Hospital mortality for AIDS patients was greater among less experienced hospitals. The difference in mortality rate was equivalent to more than four additional deaths per 100 patients with AIDS admitted to the least experienced hospitals. This finding was not explained by severity of illness, comorbidity, or other case-mix variables.