SURGICAL RATES IN SUBPROVINCIAL AREAS ACROSS CANADA - RANKINGS OF 39 PROCEDURES IN ORDER OF VARIATION

OBJECTIVE: To rank 39 surgical procedures in order of variation of inp atient surgical rates, according to a new index of variation and to te st the hypothesis that there is greater variation for primarily discre tionary operations than for primarily non-discretionary operations. DE SIGN: A population-based retrospective cohort study. SETTING: Nine pro vinces (99.19% of Canada's population). PARTICIPANTS: All hospital inp atients who underwent any of 39 types of surgery and were separated fr om hospital between Apr. 1, 1988 and Mar. 31, 1990 (the most recent ti me period for which Canada-wide data were available at the subprovinci al level analysed). MAIN OUTCOME MEASURE: Rankings of the 39 procedure s according to the index of variation, calculated from inpatient surge ry rates in 255 census divisions across Canada. RESULTS: The 13 proced ures with the greatest variation a ere all primarily discretionary. Th irteen of the 14 procedures with the lowest variation were primarily n on-discretionary. All but one of the procedures whose degree of discre tion was deemed intermediate were in the middle third of the rankings. CONCLUSIONS: The greatest variation is found in primarily discretiona ry operations. Further investigation should be focused on identified g eographical locations where rates for operations that are primarily di scretionary are unusually high or low, and particularly on those opera tions for which there is disagreement regarding the indications for su rgery.