Does the Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program bariatric risk/benefit calculator hold its weight? An assessment of its accuracy.

BACKGROUND

Bariatric clinical calculators have already been implemented in clinical practice to provide objective predictions of complications and outcomes. The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Surgical Risk/Benefit Calculator is the most comprehensive risk calculator in bariatric surgery.

OBJECTIVES

Evaluate the accuracy of the calculator predictions regarding the 30-day complication risk, 1-year weight loss outcomes, and comorbidity resolution.

SETTING

MBSAQIP-accredited center.

METHODS

All adult patients who underwent primary laparoscopic Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy at our institution between 2012 and 2019 were included. Baseline characteristics were used to generate the individualized outcome predictions for each patient through the bariatric risk calculator and were compared to actual patient outcomes. Statistical analysis was performed using c-statistics, linear regression models, and McNemmar chi-square test.

RESULTS

One thousand four hundred fifty-three patients with a median age of 45 (37, 55) and consisting of 80.1% females were included in the study. The c-statistics for the complications and comorbidity resolution ranged from .533 for obstructive sleep apnea remission to .675 for 30-day reoperation. The number of comorbidity resolutions predicted by the calculator was significantly higher than the actual remissions for diabetes, hyperlipidemia, hypertension and obstructive sleep apnea (P < .001). On average, the calculator body mass index (BMI) predictions deviated from the observed BMI measurement by 3.24 kg/m. The RYGB procedure (Coef -.89; P = .005) and preoperative BMI (Coef -.4; P = .012) were risk factors associated with larger absolute difference between the predicted and observed BMI.

CONCLUSIONS

The MBSAQIP Surgical Risk/Benefit Calculator prediction models for 1-year BMI, 30-day reoperation, and reintervention risks were fairly well calibrated with an acceptable level of discrimination except for obstructive sleep apnea remission. The 1-year BMI estimations were less accurate for RYGB patients and cases with very high or low preoperative BMI measurements. Therefore, the bariatric risk calculator constitutes a helpful tool that has a place in preoperative counseling.