Applicability of the GLIM criteria in Vietnam: Diagnostic performance of calf and mid-upper arm circumference for assessment of muscle mass reduction in older adults

<h2>Abstract</h2><h3>Background</h3> The GLIM framework defines malnutrition based on three phenotypic and two etiologic criteria. Advanced methods for muscle mass assessment such as DXA, CT, and BIA are often unavailable in Vietnam due to resource constraints. This study aimed to explore potential cutoff points for calf circumference (CC) and mid-upper arm circumference (MUAC) and to evaluate their diagnostic performance in assessing reduced muscle mass under the GLIM framework. <h3>Methods</h3> A cross-sectional study was conducted among 200 hospitalized patients aged ≥60 years. Anthropometric indicators (BMI, CC, MUAC), body composition (fat-free mass index, FFMI, via BIA), and handgrip strength were collected. Malnutrition was diagnosed according to GLIM criteria. <h3>Results</h3> Based on GLIM with muscle mass reduction assessed by BIA, 54% of patients were malnourished (39% moderate, 15% severe). Unintentional weight loss had the highest sensitivity (98%), while low FFMI showed the highest specificity (86.4%) and positive predictive value (89.6%). Diagnostic accuracy was highest for FFMI (AUC = 0.85), followed by weight loss (AUC = 0.80). CC and MUAC also showed good performance with AUCs of 0.87 and 0.85, respectively. Optimal cutoffs for severe muscle mass reduction were CC <26 cm (men), <25 cm (women), and MUAC <20 cm (both sexes). The agreement in diagnosing malnutrition according to GLIM using different methods for assessing muscle mass reduction (FFMI, MUAC, CC) was high (Kappa = 0.89–0.91; p < 0.001). <h3>Conclusion</h3> In resource-limited settings where DXA, CT, and BIA are not feasible, CC and MUAC provide practical and reliable alternatives for assessing muscle mass reduction under the GLIM criteria.