Improvement in Muscle Strength and Metabolic Parameters Despite Muscle Mass Loss in the Initial Six Months After Bariatric Surgery

Background An aggravation in pre-existing sarcopenia or the onset of sarcopenia may occur in the scenario of extensive and fast weight loss in the initial months following bariatric surgery. The accurate identification of sarcopenia criteria and its metabolic repercussions is vital for its correct management. The aim of this study is to evaluate the correlation between the diagnosis criteria for sarcopenia and metabolic repercussions during the first 6 months following bariatric surgery. Methods A prospective single-center cohort study was conducted. Convenience sampling was performed among patients with severe obesity undergoing preoperative evaluation for bariatric surgery. Metabolic parameters, nutritional evaluation, and skeletal muscle evaluation were assessed before surgery and 6 months later. Results A total of 129 patients were selected, 62 participants were included in the final analysis. Mean age was 37.7 years and 88.4% of participants were women. Mean body mass index was 41.8 kg/m2 and 47.8% of patients were sedentary. Sleeve gastrectomy was performed in 41 patients and Roux-en-Y gastric bypass in 21 patients. Significant improvement regarding muscle strength and function after surgery was observed. Sarcopenia criteria were not met by any participant before and after surgery. Blood glucose and ferritin levels remained independently associated with change in muscle strength. Conclusions Functional evaluation methods did not reflect the reduction in skeletal muscle mass demonstrated in bioelectrical impedance analysis 6 months after bariatric surgery in comparison to the preoperative baseline. Improvement in muscle strength was followed by improvement in metabolic parameters.