MBSC - Weigh the Odds

Functionality & Mechanism

Developed by the Michigan Bariatric Surgery Collaborative, this clinical decision support tool provides risk stratification for bariatric surgery candidates. The system leverages validated prediction models to generate patient-specific outcomes. By processing clinical data such as comorbidities, demographics, and planned procedure type, the interface calculates projected 1-year weight loss, 30-day serious complication risk, and venous thromboembolism (VTE) probability. The VTE module also generates risk-stratified treatment guidelines, facilitating informed preoperative counseling and surgical planning.

Evidence & Research Context

• The core risk prediction models were developed and internally validated using a prospective clinical registry of over 25,000 bariatric surgery patients in Michigan.
• The weight loss calculator was validated in a U.S. Hispanic population (N=276), demonstrating strong agreement between predicted and actual 1-year weight (concordance correlation coefficient = .80).
• An external validation study (N=51,291) in a Dutch population confirmed the serious complication model has good calibration, indicating its generalizability outside the original development cohort.
• A retrospective study (N=1,050) demonstrated the calculator's utility in identifying patients at risk for lower-than-expected weight loss as early as two months post-surgery.
• The venous thromboembolism (VTE) risk model was derived from an analysis of 27,818 patients, identifying significant predictors for risk stratification and prophylaxis guidance.

Intended Use & Scope

This tool is designed for bariatric surgeons and clinicians for preoperative risk assessment and patient counseling. Its primary utility is to facilitate shared decision-making by quantifying individualized outcome probabilities. The calculator provides risk estimates, not diagnostic certainties, and is not a substitute for comprehensive clinical evaluation and professional judgment.