SUN-542 Comparison of Different Muscle Mass Indices for Evaluation of Low Muscle Mass Regarding Muscle Function, Bone Mineral Density and Metabolic Profile in Obese Patients Prior to Bariatric Surgery

Sarcopenic obesity increases the risk of metabolic complications (MC), falls, fractures and even increased mortality. The identification of a low muscle mass (LMM) occurs through the muscle mass index (MMI). The height-adjusted MMI in the elderly is the most used for the diagnosis of sarcopenia (SARC). However, in the young obese subject there is data in the literature favoring the weight-adjusted MMI, due to a better identification of SARC and correlation with MC. Objective: To identify obese patients with low muscle mass (O-LMM) prior to bariatric surgery through three different MMIs regarding muscle function (hand grip (HG) and gait velocity (GV)), bone mineral density (BMD) and metabolic profile. Methods: The cross-sectional study, involving 59 obese women of a public hospital in Brazil, was conducted. The sample was divided into two groups according to the presence of O-LMM and obese patients with normal muscle mass (O-NMM) for each IMM. We considered O-LMM patients who were in the lowest quintile for each IMM and the patients who were in the other quintiles were considered as O-NMM. The body composition was evaluated by bio-impedance (inbody-370), multifrequency (5, 50, 250 HZ), with fasting of 12 hours and BMD by lunar densitometer prodigy advance. To estimate muscle mass, the following MMIs were used: height-adjusted MMI (MMI-height): appendicular muscle mass (AMM) / height(2); MMI adjusted for weight (MMI-weight): AMM / weight x 100 and MMI adjusted for body mass index (MMI-BMI): MMA / BMI. The HG was evaluated by jamar dynamometer (3 measurements with interval of 30 seconds between them) and the physical performance by the GV for 6 minutes. Fasting glycemia, HbA1c, HOMA-IR, insulin, total cholesterol, HDL, LDL, triglycerides and high sensitivity quantitative C-reactive protein were assessed. Results: The participants had a mean age of 39.53 ± 8,99 years, weight: 108.60 ± 13.86 kg and BMI: 42.6 ± 4.64 kg / m(2). O-LMM were identified at 30.5% (n = 18) by MMI-weight, and also at 20.33% by MMI-BMI and MMI-height. Patients in the lowest quintile for the MMI-weight had a lower HG (24.16 x 30.69 kg, p = 0.000), lower BMD in L1-L4 (1.17 x 1.27 g / cm(2), p = 0.001), in the femoral neck (FN) ( 1.04 x 1.14 g / cm(2), p = 0.012) and in the total femur (TF) (1.10 x 1.19 g / cm(2), p = 0.039), respectively, but without significant difference for GV. For MMI-BMI, O-LMM presented lower GV (0.93 x 1.06 m / s, p = 0.017) and HG (23.19 x 30.22 kg, p = 0.000), however without significant difference for BMD. The O-LMM identified by the MMI-height had lower BMD in FN (1.01 x 1.13 g / cm(2), p = 0.009) and TF (1.06 x 1.19 g / cm(2), p = 0.012), with no significant difference for muscle function. Metabolic profile was not worse in the O-LMM by the three MMIs. Conclusion: The MMI-weight identifies more O-LMM patients than the other MMI. The O-LMM diagnosed by MMI-weight had lower BMD in all sites and lower HG than O-NMM, possibly being a better IMM to diagnose SARC in obese patients.