Mortality differences between New York City municipal and voluntary hospitals, for selected conditions.

To determine if mortality differences between municipal and voluntary hospitals in New York City persist after adjustment for computerized administrative data (age, sex, principal diagnosis, and secondary diagnosis), six conditions in those hospitals from 1984 through 1987 were studied. Unadjusted mortality was significantly higher in municipal hospitals for myocardial infarction, stroke, and head trauma, and lower for congestive heart failure and pneumonia. Adjustment using administrative data eliminated differences for myocardial infarction, congestive heart failure, and pneumonia, but not for stroke and head trauma. We conclude that adjustment using administrative data eliminates some but not all mortality differences between municipal and voluntary hospitals. Medical record review is needed to determine why these differences persist.