Variation in the practice of cholecystectomy for benign biliary disease in Aotearoa New Zealand: a population-based cohort study

Introduction: Cholecystectomy for benign biliary disease is common and its delivery should be standardised. However, the current practice of cholecystectomy in Aotearoa New Zealand is unknown.Methods: A prospective, national cohort study of consecutive patients having cholecystectomy for benign biliary disease was performed between August and October 2021 with 30-day follow-up, through STRATA, a student-and trainee-led collaborative.Results: Data were collected for 1171 patients from 16 centres. 651 (55.6%) had an acute operation at index admission, 304 (26.0%) had delayed cholecystectomy following a previous admission, and 216 (18.4%) had an elective operation with no preceding acute admissions. The median adjusted rate of index cholecystectomy (as a proportion of index and delayed cholecystectomy) was 71.9% (range 27.2%-87.3%). The median adjusted rate of elective cholecystectomy (as proportion of all cholecys-tectomies) was 20.8% (range 6.7%-35.4%). Variations across centres were significant (p < 0.001) and inadequately explained by patient, operative, or hospital-factors (index cholecystectomy model R-2 = 25.8, elective cholecystectomy model R-2 = 50.6).Conclusions: Notable variation in the rates of index and elective cholecystectomy exists in Aotearoa New Zealand not attributable to patient, operative or hospital factors alone. National quality improvement efforts to standardise availability of cholecystectomy are needed.