Robotic Use, Operative Length, and Readmission after Duodenal Switch: A Retrospective Ten-Year MBSAQIP Analysis Using an Interaction Model

BACKGROUND: Robotic-assisted surgery (RAS) is increasingly used in bariatric practice, yet its impact on outcomes after duodenal switch (DS) remains poorly characterized, and whether operative length (OL) modifies the RAS-outcome association has not been assessed. The present study examines the independent and interactive effects of RAS and OL on 30-day readmission after DS using a national cohort of over 17,000 cases from the MBSAQIP database spanning 2015-2024. METHODS: We analyzed MBSAQIP data from 2015 to 2024 for patients undergoing laparoscopic DS (CPT 43845), excluding open, endoscopic, hand-assisted, and single-incision, revision, and conversion cases. Multivariable logistic regression assessed predictors of 30-day readmission, with a pre-specified interaction term between RAS and standardized OL to isolate the independent contribution of robotic use. RESULTS: Among 17,615 DS cases, 5,496 (31.2%) were robotic-assisted. Thirty-day readmission was higher after RAS than laparoscopic DS (6.2% vs. 5.0%, p < 0.01). In adjusted models, RAS (OR 1.78, 95% CI 1.25-2.55, p < 0.05) and OL (OR 1.27 per standard deviation (SD), 95% CI 1.18-1.38, p < 0.001) were independently associated with increased odds of readmission. The RAS-OL interaction significantly improved model fit (likelihood ratio p = 0.007); each SD decrease in OL increased the relative readmission risk for RAS versus laparoscopic cases (interaction OR 0.79, 95% CI 0.67-0.94, p < 0.05). Temporal subgroup analysis shows this disadvantage was concentrated in 2015-2019. CONCLUSIONS: RAS for DS is associated with higher 30-day readmission, and OL significantly modifies this relationship. The interaction term suggests that improved operative efficiency will not resolve the RAS readmission disadvantage.