Nationwide Practice Patterns of Early Postoperative Kampo Medicine after Gastrectomy for Gastric Cancer: A Japanese Administrative Database Study.

PURPOSE: Kampo medicines are incorporated into early postoperative supportive care in Japan, but nationwide real-world data after gastrectomy are limited. We characterized early postoperative use of Daikenchuto and Rikkunshito and explored postoperative length of stay (LOS) as a secondary descriptive outcome. METHODS: Using a Japanese Diagnosis Procedure Combination administrative database from 472 hospitals (August 2017-July 2022), we identified adults undergoing gastrectomy for gastric cancer. Early postoperative use was defined as administration within 7 postoperative days. Prescription rates were compared by hospital characteristics and surgical procedure (open vs. laparoscopic distal, total, and proximal gastrectomy). Postoperative LOS was calculated from surgery to discharge. RESULTS: Among 26,097 eligible patients, 1,797 (6.9%) received Daikenchuto and 2,309 (8.8%) received Rikkunshito. Daikenchuto was more frequently used after open than laparoscopic surgery (8.3% vs. 5.7%) and was most often prescribed after open distal (8.9%) and open total gastrectomy (7.6%). Rikkunshito was more frequently prescribed in designated cancer hospitals and large hospitals (≥500 beds), and after distal or proximal gastrectomy than total gastrectomy (9.6% vs 6.3%). The median postoperative LOS was 12 days among Daikenchuto users versus 11 days among non-users, and 10 days among Rikkunshito users versus 11 days among non-users. CONCLUSION: Early postoperative Kampo prescribing after gastrectomy differed across institutions and surgical procedures. The principal finding of this study was nationwide variation in prescribing patterns. Postoperative LOS differed descriptively between users and non-users, although these comparisons were unadjusted and subject to substantial time-dependent and clinical confounding.