Association of Low Lean Mass With Frailty and Physical Performance: A Comparison Between Two Operational Definitions of Sarcopenia-Data From the Berlin Aging Study II (BASE-II)

Background. For prevention and treatment of sarcopenia, defined as a decline in lean mass, reliable diagnostic criteria and cutpoints reflecting a clinically relevant threshold are indispensable. As of yet, various parameters have been proposed but no gold standard exists. The aim of this study was to compare cutpoints of appendicular lean mass related to body mass index (ALM(BMI)) or height (ALM/height(2)) regarding their association with self-reported physical limitations and frailty status in a sample of community-dwelling older adults. Methods. A total of 1,343 participants from the Berlin Aging Study II were included. ALM index was assessed with dual-energy X-ray absorptiometry. Limitations in physical performance were assessed via questionnaire and frailty status was defined according to the Fried criteria. Results. In a risk factor-adjusted analysis, participants with an ALM(BMI) below the cutpoints had 1.4-2.8 times higher odds of difficulties in several domains of physical activity (p = .031 to p < .0001) compared with participants with normal ALM(BMI). In participants with low ALM/height(2), no associations with physical limitations were found. Moreover, the odds of being prefrail/frail were statistically significant for the low ALM BMI group only (odds ratio = 2.403, 95% confidence interval: 1.671-3.454, p < .0001) and not for the low ALM/height(2) group. Conclusions. This study showed striking differences between the two operational criteria ALM/height(2) and ALM(BMI) concerning their association with physical limitations and prefrailty/frailty. The low ALM(BMI) cutpoints seem suitable to detect patients at risk for negative outcomes such as frailty who might benefit from interventions targeted at improving lean mass.