Beyond Sarcopenia: A Systematic Review and Meta-Analysis on Muscle Outcomes After Bariatric Surgery.
Gabriël Eksteen, Lore Dubois, Bart Van der Schueren et al.
✦ AI-curated · Sources linked
In 30 seconds
This systematic review and meta-analysis examined longitudinal and cross-sectional evidence on muscle quantity, strength, and physical performance after metabolic and bariatric surgery, excluding studies with muscle-preserving interventions. Across 66 reports from 64 studies, absolute muscle quantity declined, with a 1-year standardized mean difference (SMD) of -0.80 (95% CI -0.97 to -0.63), while relative muscle mass generally increased. Greater total weight loss predicted larger absolute muscle losses. Despite these changes, lower-body functional strength and physical performance generally improved, and muscle loss did not consistently correspond to impaired functional capacity.
Key findings
- Absolute muscle quantity declined after surgery; at 1 year, SMD was -0.80 (95% CI -0.97 to -0.63).
- Relative muscle mass generally increased, and greater total weight loss predicted larger absolute muscle losses.
- Lower-body functional strength and physical performance generally improved, while absolute arm and leg strength modestly declined or remained stable.
- Comparisons with non-surgical controls showed no consistent differences in muscle outcomes, with high heterogeneity.
Why it matters
Muscle quantity can fall during substantial weight reduction without a corresponding decline in functional capacity. Interpreting absolute muscle loss alone may therefore mischaracterize its clinical significance. The review highlights the value of assessing muscle changes alongside weight loss, strength, and performance, and of using standardized measures and obesity-specific reference data to distinguish adaptive changes from meaningful impairment.
What to keep in mind
The included studies covered diverse procedures and populations, and cross-sectional comparisons with non-surgical controls had high heterogeneity.