A nomogram based on clinical factors to predict the serum myoglobin levels following bariatric surgery

Background:

Increased serum myoglobin levels following bariatric surgery can predict rhabdomyolysis, a severe postoperative complication, which can induce acute kidney injury (AKI). The aim of this study is to develop a nomogram based on clinical factors to predict increased postoperative serum myoglobin levels following bariatric surgery.

Materials and methods:

Serum myoglobin levels were studied pre- and postoperatively in 281 obese patients (34.5 males, 65.5% females) undergoing bariatric surgery in the division of bariatric surgery in the University Hospital Leipzig, Germany between May 2012 and July 2015. The median BMI was 50.2 kg/m2 (range 29 – 87 kg/m2). A logistic regression model using stepwise model selection and hence a nomogram for postoperative serum myoglobin levels after bariatric surgery with statistically significant covariates were established.

Results:

Increased serum myoglobin levels were detected firstly 4 hours directly after bariatric surgery (median 124 ng/ml, range 25 – 22064 ng/ml). On multivariable analysis, age, body mass index (BMI), presence of Diabetes Mellitus type II, duration of bariatric surgery and preoperative serum myoglobin levels were significant predictors for increased serum myoglobin levels postoperatively. Furthermore, the patients were classified according to bariatric surgery duration and BMI into groups. Patients with BMI ≥60 kg/m2 and operating time (OP-time) ≥160 min demonstrated the highest postoperative serum myoglobin levels (28% with values ≥3000 ng/ml) and had significantly higher postoperative morbidity including rhabdomyolysis, AKI and compartment syndrome.

Conclusion:

We provide a clinical nomogram for prediction of serum myoglobin levels following bariatric surgery, which may improve clinicians' abilities to predict bariatric patients in risk of developing rhabdomyolysis during the postoperative course.