The impact of bariatric surgery and exercise on systemic immune inflammation index in patients with sarcopenia obesity
Authors: Mendes Cláudia , Carvalho Manuel , Bravo Jorge , Martins Sandra , Raimundo Armando 
Published: February 2025

The role of obesity in contributing to inflammation is an influential factor in the progression of obesity-associated medical issues. Metabolic and bariatric surgery has been proven as effective in obtaining weight loss and associated conditions remission. The Systemic Immune Inflammation Index (SII) was developed to offer more comprehensive data on inflammation and is presented as a prognostic indicator regarding many adverse conditions. The present study aimed to investigate the association between SII and bariatric surgery in patients with sarcopenic obesity and evaluate the eventual impact of exercise on SII. All participants were sarcopenic patients with obesity, underwent bariatric surgery - RYGP - and were randomized to participate in a structured physical exercise or to control group. The assessments were performed following standardized procedures, with the data evaluated during routine clinic follow-up at preoperative and 20-weeks postoperative after the exercise program. At baseline, before surgery, patients in both groups had similar anthropometrics, body composition, muscle strength variables and percentage of comorbidities. SII was also similar in both groups. To better understand the association of SII with the different variables, a Pearson correlation test was performed at baseline using SII. There was an inverse association of SII with BMC, handgrip strength and ASMM at baseline, which was maintained 5 months after surgery. At the end of the study, the combined results of the two groups showed that weight, BMI, % of body fat, muscle mass and muscle strength, the 30s sit-to-stand test and bone mineral density all decreased significantly as expected, along with the SII that also decreased significantly. The intervention group showed higher ASMM, handgrip strength, 30s Sit-to-stand test and 400-m walk test and bone mineral density when compared with the control group. However, SII showed no difference between both groups (p > 0.05). The results of the current research show a positive impact of bariatric surgery on weight and associated conditions control and a negative impact on muscle mass and function. SII responded very favorably to surgery with or without exercise, with a clear decrease in its score. Higher SII is associated with lower muscle mass and function, and this may be a reflex of the compromise that obesity causes on health, in this case, increasing systemic inflammation and decreasing muscle mass and function. The role of physical exercise in the management of surgical bariatric patients is still not clear. After surgery, the patients in the physical exercise program group had better results in muscle mass and function when compared to the patients in the control group (without exercise). However, there were no differences in SII score between the two groups, which may be interpreted as a lack of positive effect of physical exercise per se in the short-term on the systemic inflammatory condition present in obesity.