Overview
The MOSI System is a research decision-support calculator for obesity severity staging, therapeutic weight-loss target estimation, and procedure-specific bariatric outcome estimates.
Affiliated Centers
Artificial Intelligence in Surgical Technologies (AIST) Lab
Surgical innovation, artificial intelligence, and clinical decision-support research.
Mayo Clinic
Academic medical center and clinical research environment supporting bariatric surgery innovation.
The MOSI System was developed as a research decision-support platform affiliated with the Artificial Intelligence in Surgical Technologies (AIST) Lab and Mayo Clinic.
Development and affiliation
Developed by the Artificial Intelligence in Surgical Technologies (AIST) Lab, Mayo Clinic.
The platform was developed as a research platform to support bariatric surgery phenotyping, clinical communication, and prospective validation.
How the calculator works
- BMI determines the M class.
- Selected metabolic and organ conditions determine the O score.
- End-organ or systemic disease determines the Si level.
- M class, O score, and Si level combine to generate the MOSI stage.
- The comorbidity profile also determines a weight-loss target tier.
- Procedure outcome estimates display SG, RYGB, and exploratory BPD-DS/SADI-S values when exact estimates are available.
Algorithm definitions
M class
M1: BMI 30.0–34.9; M2: 35.0–39.9; M3: 40.0–44.9; M4: 45.0–49.9; M5: BMI ≥50.0.
O score
One point each for hypertension, dysglycemia, obstructive sleep apnea, and hyperlipidemia. GERD is not part of O score.
Si level
Si0: no end-organ involvement. Si1: diabetic microvascular/end-organ disease. Si2: major organ dysfunction. Si3: dialysis-dependent renal failure or solid-organ transplant recipient status.
MOSI stage
- Stage IV: Si3.
- Stage IV-A: transplant without dialysis.
- Stage IV-B: dialysis, with or without transplant.
- Stage III: Si2, or Si1 with M ≥4 or O ≥3.
- Stage I: Si0 with M ≤2 and O ≤1.
- Stage II: all remaining combinations.
Weight-loss target tiers
Tier A: ≥7.5% TWL. Tier B: ≥15% TWL. Tier C: ≥25% TWL. Tier D: ≥30% TWL. Highest qualifying tier wins.
Bariatric procedure outcome estimates
SG, RYGB, and exploratory BPD-DS/SADI-S probabilities are shown at 12 and 60 months when exact values are available. Missing cells remain N/A.
In methodology documentation, MOSI-S refers to severity stage, MOSI-T to therapeutic target, and MOSI-D to decision-support estimates.
Study data summary
Staged cohortn = 3,192
12-month cohortn = 2,939
Primary endpointTWL ≥20%
Stage I191 · 91.6%
Stage II1,542 · 87.4%
Stage III1,297 · 80.3%
Stage IV162 · 58.5%
Stage IV-A86
Stage IV-B76
AUC0.761
AUC + age + sex0.789
DeLongp = 0.049 / 0.49
Tier A248
Tier B654
Tier C1,549
Tier D488
Stage distribution: Stage I 191; Stage II 1,542; Stage III 1,297; Stage IV 162; Stage IV-A 86; Stage IV-B 76. 12-month TWL ≥20% success: Stage I 91.6%; Stage II 87.4%; Stage III 80.3%; Stage IV 58.5%.
MOSI + Procedure AUC: 0.761. MOSI + Procedure + Age + Sex AUC: 0.789. DeLong comparisons: MOSI+Procedure vs BMI+Procedure p = 0.049; MOSI+Procedure vs EOSS-proxy+Procedure p = 0.49. Target-tier distribution: Tier A 248; Tier B 654; Tier C 1,549; Tier D 488.
Limitations
- Retrospective single-center derivation.
- Observational procedure comparisons and possible procedure-selection bias.
- Smaller Stage IV and BPD-DS/SADI-S subgroups.
- 60-month attrition.
- Research decision-support only; not a medical device and not a substitute for clinician judgment.
Although age and sex were included in a fully adjusted performance model, the active calculator displays stage- and procedure-based retrospective estimates rather than individualized coefficient-based predictions. The active estimate display focuses on 12-month and 60-month horizons. Entered features are interpreted as present when selected; unselected features are treated as absent for this calculator.
This static calculator runs in the browser and does not store or submit entered values.