Five-year study of surgical rates in Ontario's counties.

The surgical rates for eight operations (hysterectomy, tonsillectomy/adenoidectomy, cholecystectomy, prostatectomy, appendectomy, mastectomy, colectomy and cesarean section) done in Ontario's 44 counties from 1973 to 1977 were examined. There was considerable variation among the counties for all the operations studied, although the degree of intercounty variation decreased over the 5 years. Differences in resources (hospital beds and surgeons) explained little of the variation in the rates, but this may be because people crossed county lines for certain operations. Although some counties had consistently high or low rates for individual operations during the 5-year period, only four had consistently high rates for four or more operations, and only five had consistently low rates for four or more. The five counties with teaching health science centres had the highest ratios of specialists and surgeons to population, and, with the exception of one county in 1973, had above-average numbers of hospital beds. Despite the greater resources in these counties, their residents had consistently low rates for cholecystectomy, appendectomy, mastectomy and tonsillectomy/adenoidectomy. However, three of these counties had the highest rates for cesarean section. The variation in the rates is likely due to lack of agreement about indications for surgery or to variation in the use of technology rather than to differences in the incidence or prevalence of disorders.