Reliability and validity of measuring temporal muscle thickness as the evaluation of sarcopenia risk and the relationship with functional outcome in older patients with acute stroke

Pre-stroke sarcopenia associated with poor functional outcomes. However, diagnosis of pre-stroke sarcopenia is often difficult in patients with acute stroke. Thus, we investigated the reliability and validity of measuring temporal muscle thickness (TMT) as an indicator of sarcopenia risk and its relationship with functional outcome in older patients with acute stroke. We conducted a cross-sectional and longitudinal study of the patients with acute elderly stroke in a single neurosurgical hospital. We measured TMT manually using brain computed tomography (CT) by two examiners. Sarcopenia risk, malnutrition risk, inflammation, comorbidities, and modified Rankin Scale (mRS) scores at 3 months after stroke were additionally assessed. Inter-rater reliability of TMT was determined by calculating the intra-class correlation coefficient ([ICC] 2,1). Multiple linear regression analyses was used to determine whether sarcopenia risk was independently associated with TMT, and logistic regression was used to evaluate the relationship between TMT and poor functional outcome (mRS > 3). A total 289 acute elderly stroke patients (163 men and 126 women; mean age: 76 years) were enrolled in this study. Regarding the reproducibility of TMT, good reliability was found; ICC2,1 = 0.759 (95 % confidence interval = 0.705–0.804). Multiple linear regression analyses for TMT after adjusting for potential confounders showed that sarcopenia risk was independently associated with TMT in older patients with acute stroke (β = -0.138, p = 0.02). After adjusting for variables, disease severity and comorbidities were the only independent predictors for poor functional outcome, but not TMT. TMT measurement using brain CT is a reliable and variable method to evaluate sarcopenia risk, but is not related to functional outcome in older patients with acute stroke.