Increased resting energy expenditure is related to plasma TNF-alpha concentration in stable COPD patients

The objective of this study was to test whether increased resting energy ex penditure (REE) in chronic obstructive pulmonary disease (COPD) patients is related to increased cost of breathing and/or to increased cytokine produc tion. In 36 non-inflammatory (CRP: 17.6 +/- 13.1 mg.l(-1), mean +/- SD; orosomuco id: 0.71 +/- 0.18 g.l(-1)), nonmalnourished (BMI: 23.6 +/- 4.3 kg.mg(-2), c linically stable, non severely hypoxic COPD patients (60.5 +/- 8.9 years) w e measured REE, pulmonary function and plasma cytokine concentrations (TNF- alpha, IL1 and IL6). REE was increased by 10 +/- 11% (P< 0.001) above predi cted values. Plasma TNF-alpha concentration was increased in all patients ( mean value 26.3 +/- 14.3 pg.ml(-1)). Excess REE (with respect to values pre dicted by Harris-Benedict equations) was correlated with plasma TNF-alpha c oncentration (P< 0.005), but not with the degree of airway obstruction, lun g overinflation, or with oxygen cost of breathing. Theophylline treatment r esulted in a significant increase in REE by 15%. In conclusion: non-malnourished, clinically stable, non-severely hypoxic CO PD patients display an increased REE that is related with plasma TNF-alpha concentration (without apparent systemic inflammation) and to theophylline treatment, but that is independent of parameters of respiratory function. ( C) 1999 Harcourt Publishers Ltd.