Impact of simple equation for estimating appendicular skeletal muscle mass in patients with stable coronary artery disease undergoing percutaneous coronary intervention

Abstract

Sarcopenia, which is evaluated based on appendicular skeletal muscle mass (ASM) using dual-energy X-ray absorptiometry and bioelectrical impedance analysis, is a prognostic predictor for adverse outcomes in patients with coronary artery disease (CAD). However, a simple equation for estimating ASM is yet to be validated in clinical practice. We enrolled 2211 patients with CAD who underwent percutaneous coronary intervention at our hospital between 2010 and 2017. The mean age was 68years and 81.5% were men. Patients were divided into 2 groups based on each ASM index (ASMI): low; male<7.3 and female<5.0 and high; male≥7.3 and female≥5.0. ASM was calculated using the following equation: 0.193×bodyweight+0.107×height-4.157×gender-0.037×age-2.631. Primary endpoints were major adverse cardiac events (MACE, which includes cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalization for heart failure), and all-cause mortality. During the median follow-up period of 4.8years, cumulative incidence of events were significantly higher in the low ASMI group. Cox proportional hazards model revealed that the low ASMI group had a significantly higher risk of primary endpoints than the high ASMI group (all-cause mortality; hazard ratio (HR): 2.13, 95% confidence interval [CI]: 1.40-3.22, p<0.001 and 4-point MACE; HR: 1.72, 95% CI: 1.12-2.62, p=0.01). Similar trends were observed after stratification by age of 65years. Low ASMI, evaluated using the aforementioned equation, is an independent predictor of MACE and all-cause mortality in patients with CAD.