Total energy expenditure in underweight patients with severe chronic obstructive pulmonary disease living at home

Aim: The aim of the study was to assess total daily energy expenditure (TDE), as measured by doubly labelled water (DLW), and describe its components in home-living underweight patients with severe chronic obstructive pulmonary disease (COPD). Methods: Basal metabolic rate (BMR) was measured prior to the study. Ten patients received DLW, followed by urine analysis by isotope ratio mass spectrometry from 10 standardised occasions during 15 days. Dietary intake was registered by each patient the first 7 days of the study. The patients were also interviewed about their physical activity pattern. Results: Measured BMR was higher than predicted in five of the 10 patients using equations from WHO. Using disease-specific equations, estimated BMR was higher for male, but not for female COPD patients. The best estimation of BMR resulted from prediction including fat-free mass. TDE varied considerably between 5200 and 11,100 kJ. Physical activity level (PAL) ranged from 1.15 to 1.80. Energy intake varied between 4500 and 9100 kJ. In underweight patients with severe COPD, TDE is highly variable, ranging from 110 to 200 kJ/kg body weight. Conclusions: This is the first study assessing and describing total energy expenditure in underweight patients with severe COPD living at home. Energy requirement in the patient group cannot solely be calculated from prediction equations. BMR should be measured and physical activity level assessed.