Diagnostic variability in sarcopenia and sarcopenic obesity among older adults: a clinical and public health...

Sarcopenia and sarcopenic obesity (SO) are highly prevalent among older adults; however, the lack of standardized diagnostic criteria compromises epidemiological comparability and clinical practice. Therefore, this study aimed to evaluate differences in the prevalence and diagnostic agreement of sarcopenia and SO according to different indicators of muscle strength and adiposity.

A cross-sectional study was conducted among 870 community-dwelling older adults. The prevalence and diagnostic agreement of sarcopenia and sarcopenic obesity (SO) were compared using different combinations of indicators of muscle strength (handgrip strength and the sit-to-stand test), muscle mass (fat-free mass index), and adiposity (BMI, waist circumference, and body fat percentage).

The prevalence of sarcopenia ranged from 9.2% (95% CI = [7.40-11.36]) to 18.8% (95% CI = [16.30-21.65]) and was significantly higher when the sit-to-stand test was used as the indicator of muscle strength (p < 0.001). The prevalence of SO ranged from 0 to 5.17% (95% CI = [3.84-6.92]; p < 0.001), with lower estimates when BMI was used as the obesity criterion (0.23%; 95% CI = [0.04-0.92]) and 0.46% (95% CI = [0.15-1.26]), and higher prevalence when body fat percentage was used (3.22%; 95% CI = [2.19-4.68]) and 5.17% (95% CI = [3.84-6.92]). Diagnostic agreement ranged from "no agreement" to "substantial agreement," with the highest agreement observed between criteria using body fat percentage (κ = 0.62; 95% CI = [0.47-0.74]).

The findings demonstrate substantial variability in the prevalence of sarcopenia and SO according to the diagnostic criteria adopted, reinforcing the need to standardize more sensitive and consistent methods for population screening and clinical decision-making among older adults.