Preserved Muscle Strength Despite Muscle Mass Loss After Bariatric Metabolic Surgery: a Systematic Review and Meta-analysis.

Background: Contrary to the previously known concept of muscle mass decrease following bariatric metabolic surgery, changes in muscle strength have been poorly investigated in systematic reviews. In this meta-analysis, we evaluated changes in handgrip strength (HGS) and lean mass (LM) after undergoing bariatric metabolic surgery.

Methods: A systematic literature review using the PubMed, Embase, and Cochrane Library databases was conducted in November 2022. Longitudinal studies reporting HGS change after bariatric metabolic surgery were eligible. Pooled estimates for changes in HGS, body mass index (BMI), LM, and fat mass (FM) were calculated. Changes from baseline to the point closest to 6 months postoperatively were analyzed in trials with multiple follow-up examinations. The risk of bias was assessed using the Joanna Briggs Institute critical appraisal checklist.

Results: Three randomized controlled trials and seven prospective cohort studies involving 301 patients were included. Follow-up evaluations were conducted 6 months postoperatively in all trials except for two, whose follow-up visits were at 18 weeks and 12 months, respectively. Pooled analysis showed reduced BMI (- 10.8 kg/m; 95% confidence interval: - 11.6 to - 9.9 kg/m), LM (- 7.4 kg; - 9.3 to - 5.4 kg), and FM (- 22.3 kg; - 25.1 to - 19.6 kg) after bariatric metabolic surgery, whereas the change in HGS was not statistically significant (- 0.46 kg; - 1.76 to 0.84 kg).

Conclusion: Despite the decreased body composition parameters, including muscle mass, strength was not impaired after bariatric metabolic surgery; this indicates that bariatric metabolic surgery is an effective weight management intervention that does not compromise strength.