The Impact of Bariatric Surgery on the Muscle Mass in Patients with Obesity: 2-Year Follow-up

PURPOSE: Bariatric surgery (BS) induces a significant and sustained weight loss in patients with severe obesity (SO). Nevertheless, apart from significantly reducing body fat, fat-free mass (FFM) might also be lost. At present, there is little and controversial data in the literature regarding the impact of BS on FFM. In recent years, bioimpedance (BIA) has emerged as a reliable test to assess body composition easily to use in the daily clinical practice. On the bases, the aim of the present study is to evaluate the impact of BS on the FFM, evaluated by means of BIA. MATERIAL AND METHODS: This is a prospective, observational study, including consecutive patients with SO that underwent BS between February 2018 and February 2019 at our center. At baseline, 1, 6, 12, and 24 months after the BS, all the patients underwent complete medical history, physical and anthropometric evaluation, and body composition assessment by means of BIA (using Bodystat QuadScan4000®). RESULTS: Eighty-five patients with SO were recruited, 72.9% females, aged 45.54 ± 9.98 years, pre-BS BMI 43.87 ± 6.52 kg/m(2). FFM significantly decreased continuously after BS at all timepoints. The loss of FFM 24 months post-BS accounted for approximately 21.71 ± 13.9% of the total weight loss, and was independent of BS technique or protein metabolism. Pre-BS HOMA-IR and FFM were independent predictors of FFM at 24 months. CONCLUSIONS: Significant and early loss of FFM in patients with SO that undergo BS was seen, not related to protein metabolism parameters or the BS technique used, suggesting an independent mechanism. GRAPHICAL ABSTRACT: [Image: see text]