Resting energy expenditure of female adolescents with phenylketonuria: agreement of predictive equations

Abstract

ObjectiveTo determine the agreement of clinically‐used, predictive equations with measured resting energy expenditure (MREE) in a group of female adolescents with phenylketonuria (PKU).MethodsMREE was measured by indirect calorimetry in 36 female adolescents (11.5‐18.7 y) with PKU. Eight predicted resting energy expenditure values were calculated from published equations for each subject and compared to MREE. The level of agreement was determined using Bland‐Altman and regression‐based methods.ResultsMREE was greater than predicted values, on average, for each equation (each p<0.005). The Schofield equation based on weight had the lowest mean underestimation of MREE (144 kcal), the largest concordance coefficient (0.626), and the most observations within +/‐10% of MREE (38.9%).ConclusionsPredictive equations underestimate MREE in female adolescents with PKU. Of the eight equations evaluated, the Schofield equation based on weight had the highest level of agreement with MREE. Accuracy at the individual level was affected by systematic bias and interpersonal variability.Funded by private donations and Emory University Hospital General Clinical Research Center.