Use of the Obesity Surgery Mortality Risk Score to Predict Complications of Laparoscopic Bariatric Surgery

Background This study aimed to evaluate the role of the Obesity Surgery Mortality Risk Score (OS-MRS) to predict the risk of post-operative adverse events, in addition to death, from any laparoscopic bariatric procedure. Methods The OS-MRS was applied to consecutive patients at a single hospital during October 2008–September 2009. The composite end point comprised one or more of the following adverse events: mortality, re-intervention, re-admission to hospital, venous thromboemobolism, or blood transfusion. Results There were 381 patients (men, 19%). The median age was 43 years (range, 19–67 years), with 42% patients aged ≥45 years. The median weight was 126 kg (75–295 kg) and median BMI 46 kg/m2 (30–84 kg/m2); 37% had BMI ≥50 kg/m2. Twenty-seven percent of patients had hypertension and 3% had a past history of venous thromboembolism. The OS-MRS classes were A (60.1%), B (35.9%), or C (4.0%). Operations comprised adjustable gastric band (37%), Roux-en-Y gastric bypass (54%), sleeve gastrectomy (8%), or biliopancreatic diversion (1%). Of the operations, 1.6% were revisional procedures. An adverse outcome occurred in 19 patients, with distribution in 3.5% of class A patients, 5.8% of class B, and 20.0% of class C (A vs. B, P = 0.451; A vs. C, P = 0.002; B vs. C, P = 0.025). There was one death: OS-MRS class C. On multivariate analysis, OS-MRS (class C vs. A or B; Odds Ratio [OR], 4; P = 0.050) and type of operation (band vs. bypass or sleeve; OR, 9.2; P = 0.033) were independently predictive of the composite end point. Conclusion OS-MRS and type of the bariatric operation are independently predictive of the risk of post-operative adverse events.