DIAGNOSTIC-ACCURACY AND SHORT-TERM SURGICAL OUTCOMES IN CASES OF SUSPECTED ACUTE APPENDICITIS

Objective: To test the hypothesis that, with modern diagnostic methods and antibiotics, more conservative use of surgery in cases of suspect ed appendicitis would not result in increased rates of short-term comp lications in confirmed cases. Design: Population-based observational s tudy using administrative data. Setting: All Ontario hospitals in whic h primary appendectomy was performed from Apr. 1, 1981, to Mar. 31, 19 92. Patients: All 126 815 patients admitted to hospital For a primary appendectomy during the study period. Outcome measures: Diagnostic acc uracy rate (acute appendicitis as the primary diagnosis), perforation rate, in-hospital death rate and length of stay. Results: The diagnost ic accuracy rate among the male patients was stable throughout the dec ade; among the female patients it rose significantly, from 71.7% in 19 81 to 75.3% in 1991 (p < 0.01). The perforation rates increased signif icantly among both the female and male patients (p < 0.01), whereas th e mean length of stay decreased (p < 0.05). Despite sex-related differ ences in the accuracy rates, the male and female patients had similar in-hospital death rates and mean lengths of stay. The institutional di agnostic accuracy rates, as determined from data for 1989-90 to 1991-9 2, ranged From 50.0% to 96.7%. Multivariate analyses of 27 189 confirm ed cases of appendicitis at 175 hospitals revealed that perforation wa s a strong predictor of in-hospital death (odds ratio [OR] 2.46, 95% c onfidence interval [CI] 1.24 to 4.88), but comorbidity was the stronge st predictor (OR 11.50, 95% CI 5.96 to 22.10). For each 10% increase i n the diagnostic accuracy rate, the perforation rate increased 14% (OR 1.14, 95% CI 1.10 to 1.19), but the accuracy rate was not significant ly related to the in-hospital death rate or the length of stay. Conclu sion: A higher diagnostic accuracy rate is associated with more perfor ated appendixes. Although perforation itself leads to adverse outcomes , a higher accuracy rate does not. This suggests that hospitals with h igher accuracy rates incur more perforations, but, with close observat ion, timely laparotomy and the use of modern antibiotics, these patien ts have favourable outcomes. This contrasts with adverse effects of pe rforation among patients at high risk for per foration (especially ver y young children and elderly people) in centres at all accuracy levels . The variation in hospitals' diagnostic accuracy rates suggests that some proportion of appendectomies could be safety avoided.