Determination of cutoff values for severe low muscle mass using calf circumference in the global leadership initiative on malnutrition (GLIM) criteria.

Background & Aims: Calf circumference is a simple and practical indicator of muscle mass. However, an appropriate cutoff value reflecting severely reduced muscle mass when using calf circumference as an indicator of muscle loss for severity assessment after malnutrition diagnosis has not yet been established. Therefore, we identified a cutoff value and evaluated its validity.

Methods: This retrospective cohort study consists of a "developmental study" to calculate cutoff values for severely reduced muscle mass and a "validation study" to verify their validity. In the "developmental study," a receiver operating characteristic analysis of calf circumference was performed by sex to determine the cutoff values for severely reduced muscle mass and 1-year mortality. In the "validation study," these cutoff values were used to stratify patients with the Global Leadership Initiative on Malnutrition (GLIM) malnutrition into no, moderate, and severe groups, followed by Cox proportional hazards analysis.

Results: In the "developmental study," the analysis was conducted using 5173 individuals, including 2784 females with an average age of 71.8 ± 15.8 years and 2389 males with an average age of 74.9 ± 12.4 years. The cutoff value for severely reduced muscle mass based on calf circumference in males was 29.8 cm (area under the curve [AUC]: 0.651 [0.626-0.675]), whereas in females, it was 28.2 cm (AUC: 0.643 [0.615-0.671]). In the "validation study," 6609 participants were analyzed, with an average age of 66.4 ± 17.1 years, including 3363 males (50.9 %). As nutritional status worsened, the HR increased (No malnutrition: HR = 1.0 [Reference], moderate malnutrition: HR = 2.74 [2.24-3.33] p < 0.001, severe malnutrition: HR = 4.74 [4.06-5.54] p < 0.001).

Conclusion: This study identified cutoff values for reduced muscle mass, assessed by calf circumference, to classify the severity of malnutrition following diagnosis based on the GLIM criteria.