ABSTRACT
OBJECTIVE: The aim of this study is to determine whether the sarcopenia index (SI) is a viable measure of muscle mass in pediatric patients with brain tumors. METHODS: Retrospectively enrolled patients (1-16 years) who had serum creatinine (Cr) and cystatin C (CysC) levels evaluated within 28 days of an abdomen magnetic resonance imaging scan for the lumbar vertebrae 3-4 total psoas muscle area (tPMA) were studied. Variables were compared using their z scores calculated from age- and sex-dependent reference. We hypothesized that a low SI indicated less skeletal muscle, and therefore potentially indicated sarcopenia. RESULTS: The SI z score had no correlation with tPMA z score (r = 0.004). Both Cr and CysC levels were positively correlated with tPMA in z scores (r = 0.249 and 0.320). tPMA strongly correlated with body mass index in z scores (r = 0.582). The z scores of tPMA, Cr and CysC decreased with elevated World Health Organization grades of tumor, but the z scores of SI showed no significant dependence on WHO grades. CONCLUSION: The correlation of SI to muscle mass is very weak in our sample of pediatric patients with brain tumor. Its viability as biomarker for sarcopenia needs more study.