Variables included in final regression models for each comorbid condition. *Based on the enhanced ICD-9 coding of the Elixhauser comorbidity classification . Hypertension combines hypertension, uncomplicated with complicated. Only used data from index encounter. †Versus not black. ‡At least once during the index hospitalization. §Excluding topical steroids. || Documented in the social history. **Single includes single, widowed, divorced and separated. ††Using ICD-9 procedure codes during index hospitalization.