Prevalence of an elevated resting energy expenditure in patients with chronic obstructive pulmonary disease in relation to body composition and lung function

Abstract

Objective: This study describes the prevalence and characteristics of an elevated resting energy expenditure (REE) in patients with chronic obstructive pulmonary disease (COPD). Design and setting: Patients were consecutively admitted to an in-patient pulmonary rehabilitation centre. Subjects: The study group consisted of 172 (123<) clinically stable patients with COPD, age mean (s.d. ) 64 (10) y). Interventions: REE was assessed by indirect calorimetry (ventilated hood) and adjusted for the in¯uence of fatfree mass (FFM; measured by bioelectrical impedance analysis) using the linear regression equations of REE on FFM generated in 92 healthy age-matched subjects (58<, age 67 (8) y) for men and women separately. The predicted REE adjusted for FFM (REEFFM) was obtained by using the FFM of each individual patient in the linear regression equation of REE on FFM generated in the healthy control group. Results: 26% of the patients were hypermetabolic (de®ned as REE b 110% REEFFM), characterized by a lower age (60 (10) vs 65 (9) y) and a lower total lung capacity (TLC; 122 (27) vs 139 (28)%pred) compared to normometabolic patients (P`0.001). The prevalence of FFM-depletion was equal among normo-and hypermetabolic patients: 36% vs 33% respectively. Depleted patients expressed however a signi®cantly higher residual volume/TLC ratio and a lower maximal inspiratory mouth pressure independently of hypermetabolism (P`0.05). In contrast, on base of the Harris & Benedict (HB) prediction equations, which do not take body composition into account, 54% of the patients were hypermetabolic (REE b 110% REEHB), characterized by a higher age and a lower body mass and FFM (P`0.05). Conclusions: Hypermetabolism commonly occurs in COPD, characterized by less hyperin¯ation at rest, in contrast to the suggested contribution of an elevated oxygen cost of breathing (OCB) to hypermetabolism in COPD. The higher hyperin¯ation at rest in FFM-depleted patients independently of hypermetabolism suggests a higher OCB during activities, contributing to the elevated total daily energy expenditure previously reported in COPD. The HB-equations overestimate the prevalence of hypermetabolism and link hypermetabolism incorrectly to aging and depletion.

Total daily energy expenditure in wasted chronic obstructive pulmonary disease patients

“…Patients with COPD have been reported to have a raised BMR ( $ 10%), partly because of an increase in the energy cost of breathing (Creutzberg et al, 1998). However, there is no universal agreement on this issue, since Ryan et al found no increase in BMR in malnourished patients with COPD (Ryan et al, 1993).…”

Activity Monitoring and Energy Expenditure in COPD Patients: A Validation Study

“…This underestimation is not surprising given that some subjects with moderate to severe COPD have been demonstrated to have increased resting and total daily EE and a greater oxygen consumption for a given workload compared to normal subjects (30). This can be attributed to reductions in skeletal muscle efficiency (31) and a higher work of breathing at a given level of ventilation likely not captured by accelerometers.…”

Nutritional depletion and its relationship to respiratory impairment in patients with chronic respiratory failure due to COPD or restrictive thoracic diseases

“…Indeed, increased oxygen cost for respiratory muscles during rest and exercise as well, and their impact on malnutrition have often been emphasized in COPD (Baarends et al, 1997;Creutzberg et al, 1998;Congleton 1999). Even more, earlier data have demonstrated that lung function impairment and augmented ventilation are correlated in both restrictive and obstructive lung diseases (Sridhar et al, 1994).…”

“…Correspondingly, we found a previously undescribed correlation between FFMI and P 0.1 as a non-invasive marker of inspiratory drive. Of course, measurements of energy expenditure are necessary to confirm the impact of respiratory mechanics on nutritional status (Creutzberg et al, 1998). Further, it cannot be excluded, however, that dyspnoea, which worsens with increasing severity of disease, has prevented adequate caloric intake (Congleton 1999, Tang et al, 2002.…”