A proposal for a fat mass index criterion for the assessment of sarcopenic obesity in the community-dwelling older women

Introduction: Among older populations, sarcopenic obesity (SO) is a prevalent condition, characterized by the coexistence of both low muscle mass and excess fat. Accurate early diagnosis is crucial for managing this disorder and preventing its associated health risks. The aim of this study is to provide a fat mass index (FMI) cutoff value for diagnosing SO in community-dwelling older women according to (Blinded) consensus. Material and methods: This cross-sectional study included a sample of older women aged 70 years and older, residing in community settings in (blinded). Results: Among the 145 included women (mean age 77.4 years), prevalence of SO was 16.6 %. A complete assessment revealed independence and adequate nutritional status, despite high levels of comorbidity. Significant between-group differences were observed in body mass index (BMI), fat mass, and brachial and waist circumferences, but not in calf circumference. Compared to women without SO, those with the condition had lower handgrip strength but performed similarly in the sit-to-stand test. Mean FMI was higher in the SO group. A ROC curve identified an FMI cutoff of >12 kg/m(2), with 77 % sensitivity and 75 % specificity, and a post-test probability of SO of 39.2 %. Conclusions: Our results indicate that FMI is a promising diagnostic tool for SO, with acceptable sensitivity and specificity values for clinical implementation. However, further research is needed to validate these findings across different populations and healthcare settings to ensure its broader applicability. (c) 2025 The Author(s). Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).