Background
Hypermetabolism is theorized in patients diagnosed with chronic kidney disease (CKD) on maintenance hemodialysis (MHD). We aimed to distinguish key disease-specific determinants of resting energy expenditure that can be used to create a predictive energy equation that more precisely establishes energy needs with the intent of preventing protein-energy wasting.
Materials and Methods
For this three-year, multi-site, cross-sectional study (N=116), eligible participants were diagnosed with CKD and on MHD for at least three months. Predictors for the model included weight, sex, age, c-reactive protein (CRP), glycosylated hemoglobin (A1C), and serum creatinine (SCr). The outcome variable was measured resting energy expenditure (mREE). Regression modeling was used to generate predictive formulas and Bland-Altman analyses to evaluate accuracy.
Results
The majority were male (60.3%), black (81.0%), non-Hispanic (76.7%) and 23% were 65 years or older. After screening for multi-collinearity, the best predictive model of mREE (R2=0.67) included weight, age, sex, and CRP. Two alternative models with acceptable predictability (R2=0.66) were derived with A1C or SCr. Using Bland-Altman analyses, the Maintenance Hemodialysis Equation with CRP included had the best precision with the highest proportion of participants’ predicted energy expenditure classified as accurate (61.2%) and the lowest number of individuals with under- or over-estimation.
Conclusions
This study confirms disease-specific factors as key determinants of mREE in patients on MHD and provides a preliminary predictive energy equation. Further prospective research is necessary in order to test the reliability and validity of this equation across diverse populations of patients on MHD.