Nationwide Trends in Perioperative Transfusion and Mortality by Hospital Surgical Volume in Biliary Tract Surgery

BACKGROUND/PURPOSE: This study evaluated associations of hospital surgical volume and perioperative transfusion with 30-day mortality in patients undergoing biliary tract surgery. METHODS: This nationwide cohort study utilized data from the Korean National Health Insurance Service to identify 641 915 patients who underwent biliary tract surgery between 2012 and 2020. The primary outcome was 30-day mortality. Perioperative transfusion was classified into four levels, and hospitals were grouped into quartiles by surgical volume. Mortality trends were evaluated using linear regression and Cochran-Armitage tests. RESULTS: The number of biliary tract surgeries increased over time, while the 30-day mortality rate declined from 0.5% to 0.3%. For all types of surgery, crude mortality increased across the transfusion-volume categories (p-trend < 0.0001). Compared with the lowest-volume hospitals, the highest-volume hospitals had higher transfusion rates (4.8% vs. 3.9%), but lower crude mortality rates among transfused patients (3.3% vs. 4.4%). Among transfused patients, volume-mortality patterns were more prominent in tertiary referral hospitals. CONCLUSIONS: Hospital surgical volume and perioperative transfusion were associated with 30-day mortality following biliary tract surgery. The higher mortality observed among transfused patients may partly reflect differences in operative complexity and clinical severity. These findings support further evaluation of selective centralization.