Work

Comparing sarcopenia risk using SARC-F, SARC-CalF, and body mass index–adjusted SARC-CalF among community-dwelling older adults in Brazil and Spain: a cross-national study

Year: 2026

Type: article

Abstract: Calf circumference (CC) is incorporated into sarcopenia screening to improve case-finding, but excess adiposity may mask low muscle mass and alter risk classification. We compared screening-based sarcopenia risk classification using SARC-F, SARC-CalF, and body mass index (BMI)-adjusted SARC-CalF among older adults from Brazil and Spain, and examined agreement, directional reclassification, and factors associated with upward reclassification after BMI adjustment of CC. This cross-sectional, cross-national study analyzed data from 327 older adults recruited in Brazil ( n = 253) and Spain ( n = 74). Screening-based sarcopenia risk classification was assessed using SARC-F, SARC-CalF, and SARC-CalF with BMI-adjusted CC. Analyses were stratified by country and age group (65–79 years; ≥80 years). Agreement was assessed with Cohen’s κ, paired changes with the exact McNemar test, and correlations between scores with Spearman’s ρ. Logistic regression identified factors associated with upward reclassification from screen-negative to screen-positive after BMI adjustment, and discrimination was quantified using the area under the receiver operating characteristic curve (AUC). The screen-positive proportion increased across tools (SARC-F 11.0%, SARC-CalF 37.3%, BMI-adjusted SARC-CalF 61.2%), with a significant between-country difference only for BMI-adjusted SARC-CalF (Spain 78.4% vs. Brazil 56.1%; p = 0.001). Agreement between SARC-F and CC-based approaches was low (κ = 0.026–0.270). BMI adjustment expanded screen-positive classification, with the largest classification shift observed among Spanish participants aged ≥ 80 years (standard vs. BMI-adjusted SARC-CalF: 39.3% upward reclassification; p < 0.001). Overweight was associated with higher odds of upward reclassification from standard to BMI-adjusted SARC-CalF (OR 3.36, 95% CI 1.68–6.73), with moderate model discrimination (AUC 0.712). BMI-adjusted SARC-CalF expanded screen-positive classification compared with SARC-F and standard SARC-CalF, indicating that these screening tools are not interchangeable. Upward reclassification was mainly associated with overweight, with the largest classification shift observed among Spanish participants aged ≥ 80 years. These findings should be interpreted as changes in screening classification, and validation against reference diagnostic criteria is needed. Not applicable.

Source: BMC Geriatrics

DOI: 10.1186/s12877-026-08139-6