Anthropometric measurements to identify undernutrition in children with cerebral palsy

Aim To evaluate the diagnostic performance of anthropometric indicators to identify undernutrition in children with cerebral palsy (CP). Method The present study was a monocentric retrospective analysis of prospectively collected data among children and adolescents with CP participating in a rehabilitation program. Undernutrition was defined as a z-score for dual-energy X-ray absorptiometry (DXA) determined body fat percentage less or equal to -2.0. The cut-off values for body mass index (BMI) of the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC), and the cut-off values for BMI and height for age of the Robert Koch Institut (RKI) were evaluated. Results In total, 329 children with CP (181 males, 148 females, Gross Motor Function Classification System levels I-V) were eligible for analysis. The mean age was 12 years 4 months (SD 2y 9mo). The BMI cut-off values showed the following sensitivities and specificities: WHO, sensitivity of 0.474 (95% confidence interval [CI] 0.244-0.711), specificity of 0.897 (95% CI: 0.857-0.928); CDC, sensitivity of 0.632 (95% CI: 0.384-0.837), specificity of 0.819 (95% CI: 0.772-0.861); RKI, sensitivity of 0.789 (95% CI: 0.544-0.939), specificity of 0.732 (95% CI: 0.679-0.781); and for height for age, sensitivity of 0.263 (95% CI: 0.091-0.512), specificity of 0.668 (95% CI: 0.612-0.720). Interpretation BMI had a high specificity but very low sensitivity in identifying undernutrition in children with CP. Z-scores for height for age had even lower specificity and sensitivity and seemed not to be appropriate for predicting undernutrition in children with CP. What this paper adds

Body mass index (BMI) z-scores had a high specificity but very low sensitivity in identifying undernutrition in children with cerebral palsy (CP). Height z-scores were not appropriate for predicting undernutrition in children with CP. Undernutrition assessed by BMI was overestimated in children with CP versus when assessed by dual-energy X-ray absorptiometry (DXA).