Análise da perda de massa muscular esquelética a partir dos achados de bioimpedância em uma coorte de pacientes submetidos à cirurgia bariátrica

Abstract

Despite the benefits from bariatric surgery, the techniques employed are not exempt from complications; among them, malnutrition stands out, which can cause important losses of muscle mass. The proposed research aims to investigate the development of Skeletal Muscle Mass (SMM) loss in individuals subjected to bariatric surgery, by means of bioimpedance analysis, since it is a simple and reproducible method. Retrospective and observational cohort type study was realized; data were only collected and after approval by the Research Ethics Committee (CAE: 37663019.8.0000.5494). The patients included in the study were attended between January 2019 and January 2020, sought service within 12 months after the surgery, and were followed up with clinical and serial bioimpedance evaluations for, at least, 6 months. The variables of interest were: epidemiological, anthropometric, pre- and post-surgery data, and results of serial bioimpedances. The average survival time until the development of low SMM was estimated by means of the Kaplan-Meier model. α = 5% was defined. Overall, 29 patients were included in the research, 79.3% of whom were female, and the sample had an average age of 38 years. An average difference of 27.6 kg in body mass was found, when compared to the last anthropometric assessment with the values prior to surgery, which proved to be statistically significant (p < 0.001). The average SMM in the first post-surgical bioimpedance was 27.5 kg. After a period of 6 months, the individuals were again evaluated and an average of 26.7 kg was obtained; the loss of SMM was statistically significant (p = 0.033). It was observed that 17.2% of the individuals presented lower SMM values below the lower limit of normality; the Kaplan-Meier survival model estimated a 40% incidence of this outcome in 40 weeks of follow-up. Therefore, the difficulty in losing weight was evidenced, since many patients maintained the body fat percentage above normal after surgery. In addition, a risk of developing SMM loss over time was observed, due to protein deficiencies imposed by the restrictive components of surgery.