Estimating Resting Energy Expenditure by Different Methods as Compared With Indirect Calorimetry for Patients With Pulmonary Hypertension.

Background: For patients with pulmonary hypertension, nutrition status is an independent predictor of morbidity and mortality, and energy expenditure can be strongly influenced by lung disease. Indirect calorimetry (IC) is the gold standard for measuring resting energy expenditure (REE), this study aimed to compare the results of REE estimated by different methods with those obtained by IC for patients with pulmonary hypertension.

Methods: In this cross-sectional study (n = 34), REE was estimated by bioelectrical impedance analysis and the predictive equations of Harris-Benedict, Food and Agriculture Organization / World Health Organization, Institute of Medicine, Cunningham, Katch-McArdle, and Mifflin-St Jeor.

Results: Mean patient age was 47.0 ± 14.5 years, and 76.5% were women. REE obtained with IC was strongly correlated with all other estimation methods but showed higher mean values: IC 1750.8 ± 434.3 kcal vs bioelectrical impedance analysis, 1549.0 ± 417.8 kcal; Harris-Benedict, 1493.1 ± 337.0 kcal; FAO/WHO, 1536.1 ± 345.0 kcal; Institute of Medicine, 1457.1 ± 293.2 kcal; Cunningham, 1597.3 ± 292.3 kcal; Katch-McArdle, 1447.7 ± 287.0 kcal; and Mifflin-St Jeor, 1388.7 ± 303.9 kcal. The analysis of agreement showed a clinically significant bias of approximately -255 kcal in all estimation methods when compared with IC.

Conclusion: Although there was a strong correlation between REE estimation methods and IC, there was no agreement between them. All estimation methods underestimated energy needs by about 255 kcal for patients with pulmonary hypertension, and the Cunningham equation had the smallest difference in relation to IC.