Indirect Calorimetry Performance Using a Handheld Device Compared to the Metabolic Cart in Outpatients with Cirrhosis

Addressing malnutrition is important to improve health outcomes in outpatients with cirrhosis, yet assessing energy requirements in this population is challenging. Predictive equations of resting energy expenditure (REE) are thought to be unreliable, and traditional indirect calorimetry is expensive and infrequently available for clinical use. The accuracy of REE predictions using a MedGem^® handheld indirect calorimeter, the Harris Benedict Equation (HBE), the Mifflin St. Jeor equation (MSJ), and the gold standard Vmax Encore^® (Vmax) metabolic cart was compared. The REE of cirrhotic pre-liver transplant outpatients was analyzed using each of the four methods. Agreement between methods was calculated using Bland-Altman analysis. Fourteen patients with cirrhosis participated, and were primarily male (71%) and malnourished (subjective global assessment (SGA) B or C 64%). Lin's concordance coefficient (ρC) for MedGem^® vs. Vmax demonstrated poor levels of precision and accuracy (ρC = 0.80, 95% confidence interval 0.55-0.92) between measures, as did the HBE compared to Vmax (ρC = 0.56, 95% confidence interval 0.19-0.79). Mean REE by MedGem^® was similar to that measured by Vmax (-1.5%); however, only 21% of REE measures by MedGem^® were within ±5% of Vmax measures. Wide variability limits the use of MedGem^® at an individual level; a more accurate and feasible method for determination of REE in patients with cirrhosis and malnutrition is needed.