Predictive score of sarcopenia occurrence one year after bariatric surgery in severely obese patients

Abstract

Background and aim: Sarcopenic obesity is a risk factor of morbidity and mortality. The aim of this study was to generate a predictive score of sarcopenia occurrence one year after bariatric surgery.

Patients and methods: We conducted an observational prospective cohort study on a total of 184 severely obese patients admitted to our institution to undergo sleeve gastrectomy. Skeletal muscle cross-sectional area at the third lumbar vertebrae (SMA, cm2) was measured from the routinely performed computed tomography. The skeletal muscle index (SMI) was calculated as follows: SMA/height2 (cm2/m2). Sarcopenia was defined as an SMI < 38.5 cm2/m2 for women and < 52.4 cm2/m2 for men. Measurements were performed at surgery and one year later.

Results: Most of the included patients were female (79%), with a mean age of 42±0.9 years and body mass index of 43.2±0.5 kg/m2. Fifteen patients (8%) had sarcopenia before surgery and 59 (32%) at the one-year follow-up. Male gender (p<0.0001), SMA before surgery (p<0.0001), and SMI before surgery (p<0.0001) significantly correlated with the occurrence of sarcopenia one year after surgery by multivariate analysis. Two predictive sarcopenia occurrence scores were constructed using SMA and gender (SS1 score) or SMI and gender (SS2 score). The area under receiver operating characteristic (AUROC) curve of the SS2 score was significantly greater than that of the SS1 score for the diagnosis of postoperative sarcopenia occurrence (0.95±0.02 versus 0.90±0.02; p<0.01). A cut-off value for the SS2 score of 0.53 had a sensitivity of 90%, a specificity of 91%, a positive predictive value of 83%, and a negative predictive value of 95%. In the group of patients without baseline sarcopenia, the SS2 score had still an excellent AUROC of 0.92±0.02. A cut-off of 0.55 predicted development of sarcopenia one year after sleeve gastrectomy in these patients with a sensitivity of 87%, a specificity of 88%, and negative predictive value of 95%.

Conclusion: The SS2 score has excellent predictive value for the occurrence of sarcopenia one year after sleeve gastrectomy. This score can be used to target early intensification of nutritional and dietetic follow-up to the predicted high-risk population.

Fig 1. ROC curves of SS2 and SS1 scores for the prediction of sarcopenia one year after sleeve gastrectomy.

The diagonal line represents the detection achieved by chance alone (AUROC = 0.50); the ideal AUROC is 1.00. The SS1 score takes into account SMA [skeletal muscle cross-sectional area at the third lumbar vertebrae (cm²)] and gender. The SS2 score takes into account SMI [skeletal muscle index: SMA/height² (cm²/m²)] and gender.