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Prognostic review and time-to-event data meta-analysis of low skeletal muscle mass in patients with peripheral arterial disease of the lower limbs undergoing revascularization.

INTRODUCTION
The relationship between low skeletal muscle mass, a surrogate of sarcopenia, and postoperative morbidity and mortality is currently being explored, with a hope to develop its role as a prognostic factor in pre-operative risk stratification. Recent evidence suggests a link between low skeletal muscle mass and outcomes of lower limb revascularization in peripheral arterial disease (PAD).


EVIDENCE ACQUISITION
A review of the literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We performed a metaanalysis for peri-interventional mortality using the odds ratio (OR) and associated 95% confidence interval (CI). For late outcomes, we conducted a time-to-event data meta-analysis using the inverse-variance method and reported the result as summary hazard ratio (HR) and associated 95% CI. We applied random-effects models of meta-analysis.


EVIDENCE SYNTHESIS
Six observational cohort studies were eligible for quantitative synthesis. In the outcome of peri-interventional mortality, we found no significant difference between patients with low skeletal muscle mass and those without (OR 1.84, 95% CI 0.40 - 8.43, P=0.43). Metaanalysis of four studies found no significant difference in overall survival between patients with and without low skeletal muscle mass (HR 1.77, 95% CI 0.58 - 5.39, P=0.32). Patients without low skeletal muscle mass were found to have a significantly longer amputation-free survival (HR 2.75 95% CI 1.82 - 4.15, P<0.00001), and a trend towards higher rates of limb salvage (HR 2.42, 95% CI 0.87 - 6.80, p=0.09) than those with low skeletal muscle mass.


CONCLUSIONS
Low muscle mass is closely associated with worse disease progression following revascularization demonstrated through lower amputation-free survival and limb salvage. More research is needed to further evaluate its prognostic value in PAD.