American Surgical Association
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Validation of the Obesity Surgery Mortality Risk Score (OS-MRS) In A Multi-Center Study Proves It Stratifies Mortality Risk In Patients Undergoing Gastric Bypass (GBP) For Morbid Obesity
Eric J DeMaria1, Michel Murr*2, T. Karl Byrne3, Robin Blackstone*4, Amanda Budak*3, Luke Wolfe*5
1Duke University, Durham, NC;2University of South Florida, Tampa, FL;3Medical University of South Carolina, Charleston, SC;4Private practice, Scottsdale, AZ;5Virginia Commonwealth University, Richmond, VA

BACKGROUND: No score for mortality risk exists for bariatric surgery. The OS-MRS was developed from a single institution, but this requires validation before acceptance. The OS-MRS assigns one point to 5 pre-operative variables including body mass index (BMI)> 50 kg/m2, male gender, hypertension, risk for pulmonary embolism, and age > 45 years. Score of 0-1 is ‘A’ (lowest) risk, score 2-3 is ‘B’ (intermediate) risk, and score 4-5 is ‘C’ (high) risk.
METHODS: 4,433 consecutive patients undergoing GBP at 3 programs were analyzed.
RESULTS: Overall mortality for the validation cohort was < 1%. Mortality in Class A, B, and C was statistically different from each of the other two classes (p < 0.05, chi-square). Mortality was 3-fold greater in the Class B group than in Class A. Only 6 patients with all 5 risk factors were identified. Class C patients (n=125, 3% of total cohort) were characterized by a 6-fold greater mortality than the lowest risk group (A) and a disproportionate 8% of all mortalities.
CONCLUSION: The OS-MRS was found to stratify risk in 4,433 patients from 3 centers that were non-participants in the original study. OS-MRS is the first validated risk scoring system in bariatric surgery and is anticipated to aid informed consent, assist surgical decision-making, and allow standardization of outcome comparisons between centers.
1141760.42A2166 (49)8 (22)0.37
3750101.33B2142 (48)26 (70)1.21
4-512532.40C125 (3)3 (8)2.40

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