Lean mass as a predictor of all-cause mortality : a systematic review and meta-analysis

Abstract

Sarcopenia is an intractable clinical condition and health challenge. Nevertheless, so far there has been no universal consensus on its definition and clinical implications. The correlation between lean body mass and mortality was reviewed and evaluated across different populations with an aim of defining sarcopenia with different cut-offs of lean body mass.

In this systematic review and meta-analysis, articles published until Dec 20, 2017 were searched from the Pubmed, Cochrane Library and Embase. Studies reporting actual lean mass measurement by dual-energy absorptiometry (DXA), bioelectrical impedance analysis (BIA) and computed tomography (CT), reported as continuous (per standard deviation [SD] decrease) or binary variables (using sarcopenia cut-offs) were included. Studies using muscle mass surrogates, anthropometric measurement of muscle, rate of change in muscle mass, sarcopenia defined using composite criteria were excluded. Studies were screened using systematic review software and data were extracted from published reports. The primary study outcome was all-cause mortality. Summary estimates were calculated using a random effects model. 9602 articles were identified, of which 241 studies were included for analysis. The all-cause mortality was 1.36 (95% CI 1.28-1.44]; I2=68%) and 1.73 (95% CI 1.63-1.85]; I2=63%) for every SD decrease in lean mass and in people with low lean mass respectively. Similar association was observed in elderly (HR=1.2 [95% CI 1.10-1.32]; I2=51%) and disease groups (HR range: 1.33-1.57). Among cancer patients, low lean mass at third lumbar level (HR=1.66 [95% CI 1.52-1.82]; I2=65%) and psoas muscle at third lumbar (HR=1.70 [95% CI 1.38-2.08]; I2=50%) were significantly associated with all-cause mortality.

The current study demonstrated that low lean mass is significantly associated with increased risk of all-cause mortality in people of different health status Similar increased risk of mortality was shown in cancer patients with low lean mass, and the significant association was observed in many cancer subtypes, except haematological malignancies, breast, ovarian and endometrium, and prostate cancer. Relationship between mortality and lean mass assessed by BIA is not inferior to DXA and CT. Development of a consistent definition of sarcopenia and addition of lean mass evaluation in disease management is warranted.