Serum creatinine: A surrogate measurement of lean body mass in children with acute lymphoblastic leukemia

BACKGROUND: Since creatinine is formed almost exclusively in skeletal muscle, the hypothesis of a relationship between serum creatinine (SC) and lean body mass (LBM), determined by dual-energy X-ray absorptiometry (DXA), was tested. METHODS: Two cohorts of patients were analyzed: 37 children with acute lymphoblastic leukemia (ALL) and 20 children with primary muscular disorders (PMD). The latter cohort was used as a comparative group. Statistical analyses were performed using linear regressions. RESULTS: A strong correlation was demonstrated between SC and LBM in the patients with PMD (r = 0.77) and in patients with ALL (r = 0.83 at diagnosis; r = 0.77 on therapy; and r = 0.56 off therapy). The correlation between SC and body size (body mass index) was much weaker (r = 0.38; r = -0.09; r = 0.29 at the successive observations in the ALL cohort and r = 0.05 in the PMD cohort). These data provide support for the initial hypothesis. CONCLUSIONS: Further investigations with a wider variety of diseases are needed for this will allow the consideration of SC as a general surrogate measure of LBM and consequently of nutritional status.