The determinants of small-area variation in hospital utilization. The evidence from hospital discharge abstracts

Small-area differences in hospital use were examined using hospital discharge abstract data for the populations of seven small service areas in Iowa that exhibited substantial variation in admission rates during 1980. The results indicate a marked difference in the age composition of the patient populations with older patients being more common among residents of high-use areas, higher age- and sex-adjusted discharge rates per 1000 in the high-use areas across many diagnostic categories, frequently higher average lengths of stay in high-use areas, a lack of conformity between discharge patterns for selected surgical procedures and diagnoses, and more readmissions to the same hospital during a 12-month period for residents of high-use areas. This data set comprises one part of a study of small-area differences that also employed household surveys, physician surveys, and other existing data sets. The findings illustrate the potential and limitations of hospital discharge abstracts as a data base for evaluating hospital discharge abstracts as a data base for evaluating hospital utilization differentials.