Muscle Strength of Lower Limbs as a Postoperative Predictor in Bariatric Surgery.

OBJECTIVE: The aim of our study was to assess postoperative lower limbs muscle strength (MS) as a predictor of late surgical success (36 months). METHODS: Body composition analyses and isokinetic dynamometry evaluation were performed before (T0: n=123), six months (T1: n=123) and 36 months (T2: n=79) after Roux-en-y gastric bypass (RYGB). Surgical success (SS) was defined as ≥ 50% excess weight loss (EWL) 36 months after surgery or ≤ 50% surgical failure (SF). RESULTS: There was no difference between relative MS extension (Ext) and flexion (Flex) in T1 and T2. There was also, no difference between relative MS Ext and Flex in T1 and T2 between patients with SS and SF. There was a difference in relative MS Ext (144.9 ± 39.8 Nm/kg x 125.5 ± 29.2 Nm/kg; p=0.04) and Flex (73.6 ± 21.8 Nm/kg x 60.4 ± 15.8 Nm/kg; p=0.02) between SS and SF patients only in T2. Patients with an increment in Ext and Flex MS ≥4 Nm/kg at T1 had approximately 76% of SS at 36 months. CONCLUSION: An increase of lower limbs MS ≥4 Nm/kg 6 months after RYGB predicts SS at 36 months. CLINICALTRIALS: gov ID: NCT04129801.

Postoperative Resting Metabolic Rate and Successful Weight Loss After Roux-en-Y Gastric Bypass.

OBJECTIVE: To analyze whether changes in RMR 6 months after RYGB could be a predictor of weight loss on late follow-up. METHODS: Prospective study of 45 individuals submitted to RYGB in a university tertiary care hospital. Body composition was evaluated by bioelectrical impedance analysis and RMR by indirect calorimetry before (T0), 6 (T1), and 36 months (T2) after surgery. RESULTS: RMR/day was lower in T1 (1.552 ± 275 kcal/day) than in T0 (1734 ± 372 kcal/day; p < 0.001) with a return to similar values at T2 (1.795 ± 396 kcal/day; p < 0.001). In T0, there was no correlation between RMR/kg and body composition. In T1, there was a negative correlation between RMR and BW, BMI, and % FM, and a positive correlation with % FFM. The results in T2 were similar to T1. There was a significant increase in RMR/kg between T0, T1, and T2 (13.6 ± 2.2 kcal/kg, 16.9 ± 2.7 kcal/kg, and 19.9 ± 3.4 kcal/kg) in the total group and according to gender. Eighty percent of the patients who had increased RMR/kg ≥ 2 kcal at T1 achieved > 50% EWL in T2, particularly in women (odds ratio: 27.09, p < 0.037). CONCLUSIONS: The increase in RMR/kg after RYGB is a major factor related to a satisfactory % excess weight loss on late follow-up.

LACTATE CAN BE A MARKER OF METABOLIC SYNDROME IN SEVERE OBESITY?

BACKGROUND: In the last decades, numerous studies have confirmed the importance of lactate - by-product to the nutrient signal of the intracellular redox state - to regulatory functions in energy metabolism. AIM: To evaluate changes in blood lactate in patients with severe obesity and its correlation with body composition and metabolic profile. METHODS: Twenty-four people with severe obesity (BMI=40 kg/m2) were evaluated in a prospective case-control study before and six months after Roux-in-Y gastric bypass. The blood lactate, total cholesterol, and fractions, C-reactive protein and HOMA-IR were analyzed after 12 h fasting. Body mass composition was evaluated by bioelectrical impedance and respiratory quotient was measured by indirect calorimetry. RESULTS: The initial lactate level was 2.5±1.1 mmol/l and returned to normal level (1.9±3.6 mmol/l, p=0.0018) after surgery. This reduction was positively correlated with a decrease in BMI (p=0.0001), % free fat mass (p=0,001), % fat mass (p=0.001) and HOMA-IR (p=0.01). There was normalization of lactatemia in 70% of patients. There was no correlation between lactatemia and C-reactive protein. CONCLUSIONS: There was a significant improvement of metabolic parameters, normalization of blood lactate, fat mass loss, although these individuals remained with a high BMI.

Lactate can be a marker of metabolic syndrome in severe obesity? / Lactato pode ser marcador da síndrome metabólica na obesidade grave?

ABSTRACT Background: In the last decades, numerous studies have confirmed the importance of lactate - by-product to the nutrient signal of the intracellular redox state - to regulatory functions in energy metabolism. Aim: To evaluate changes in blood lactate in patients with severe obesity and its correlation with body composition and metabolic profile. Methods: Twenty-four people with severe obesity (BMI=40 kg/m2) were evaluated in a prospective case-control study before and six months after Roux-in-Y gastric bypass. The blood lactate, total cholesterol, and fractions, C-reactive protein and HOMA-IR were analyzed after 12 h fasting. Body mass composition was evaluated by bioelectrical impedance and respiratory quotient was measured by indirect calorimetry. Results: The initial lactate level was 2.5±1.1 mmol/l and returned to normal level (1.9±3.6 mmol/l, p=0.0018) after surgery. This reduction was positively correlated with a decrease in BMI (p=0.0001), % free fat mass (p=0,001), % fat mass (p=0.001) and HOMA-IR (p=0.01). There was normalization of lactatemia in 70% of patients. There was no correlation between lactatemia and C-reactive protein. Conclusions: There was a significant improvement of metabolic parameters, normalization of blood lactate, fat mass loss, although these individuals remained with a high BMI.

RESUMO Racional: Nas últimas décadas, inúmeros estudos confirmam a importância do lactato - subproduto ao sinal de nutrientes do estado redox intracelular - às funções reguladoras do metabolismo energético. Objetivo: Avaliar alterações no lactato sanguíneo em pacientes com obesidade grave e sua correlação com a composição corporal e o perfil metabólico. Métodos: Vinte e quatro pacientes com obesidade grave (IMC=40 kg/m2) foram avaliadas em um estudo prospectivo antes e após seis meses do bypass gástrico em Y-de-Roux. O lactato sanguíneo, colesterol total e frações, proteína C-reativa e HOMA-IR foram analisados após 12h de jejum. A composição corporal foi avaliada por bioimpedância elétrica e o quociente respiratório por calorimetria indireta. Resultados: O nível inicial de lactato foi de 2,5±1,1 mmol/l e retornou ao nível normal após a operação (1,9±3,6 mmol/l, p=0,0018). Essa redução foi correlacionada positivamente com a diminuição do IMC (p=0,0001), % de massa livre de gordura (p=0,001) e % de massa de gordura (p=0,001) e HOMA-IR (p=0,01). Houve normalização da lactatemia em 70% dos pacientes. Não houve correlação entre lactatemia e proteína C-reativa. Conclusões: Houve melhora significativa dos parâmetros metabólicos e normalização da lactatemia, perda de massa gorda, embora esses indivíduos permanecessem com IMC elevado.

Anemia Before and After Roux-en-Y Gastric Bypass: Prevalence and Evolution on Long-Term Follow-up.

PURPOSE: Anemia due to iron deficiency or inflammatory state is often associated with obesity. Bariatric surgery is responsible for increasing iron deficiency, but weight loss decreases the inflammatory state associated with obesity. The objective of our study was to investigate the prevalence and causes of anemia before and after bariatric surgery for severe obesity in a 5-year follow-up. MATERIALS AND METHODS: Retrospective study, with electronic record analysis of obese patients, submitted to Roux-en-Y gastric bypass. Laboratory data were collected before and up to 60 months after surgery. Diagnosis and classification of anemia were done according to hemoglobin levels, serum ferritin, and transferrin saturation. RESULTS: Preoperatively, 8.8% of patients had anemia (93.2%, mild), and 43.8% of the patients had anemia due to chronic disease. After 24 months, there was a progressive increase of iron-deficiency anemia (72.4%) and decrease in anemia due to chronic disease (15.5%) and mixed (12.1%), with maintenance of this profile during long-term follow-up. CONCLUSION: Anemia is very frequent in severely obese patients and must be investigated both before and after bariatric surgery. The cause of anemia must be determined in order to use the best treatment available. We observed a reduction in the prevalence of chronic disease anemia during long-term follow-up probably due to the improvement in the systemic inflammatory state.

Resting metabolic rate and weight loss after bariatric surgery.

BACKGROUND: There is an increased interest in understanding how variation in body composition (BC) and energy expenditure is related to successful weight loss after surgery. It has been suggested that low resting metabolic rate (RMR) could be associated with poor weight loss. OBJECTIVES: To determine the relation among changes in BC, RMR, and weight loss after bariatric surgery. SETTING: University tertiary care hospital, Brazil. METHODS: A cohort of 45 patients submitted to bariatric surgery was prospectively studied. BC was evaluated by bioelectrical impedance analysis and RMR by indirect calorimetry before and 6 months after surgery. The RMR value was adjusted per kilogram of weight (RMR/kg). The patients were divided in 4 groups, based on patterns of change in the RMR/kg after surgery. The RMR/kg could decrease (group 1), remain stable (group 2), have a small increase (group 3), or have a major increase (group 4). RESULTS: A significant relation between fat-free mass and RMR for both pre- (P<.01) and postoperative periods (P<.01) was observed. Excess weight loss had a significantly correlation only with post-RMR/kg (P<.01). The pattern of change in RMR/kg was strongly correlated with weight loss, considering an excess weight loss>50% a successful weight loss: No patients achieved success in group 1; 61% of patients did in group 2; 80% di in group 3; and all patients in group 4 had successful weight loss. CONCLUSIONS: We demonstrate a clearly correlation between the postoperative RMR and weight loss. The increase in RMR/kg after surgery is a major factor related to a satisfactory excess weight loss after surgery.