BACKGROUND: Few studies have measured the resting energy expenditure (REE) in patients with interstitial lung disease (ILD). Whether REE characteristics in patients with chronic obstructive pulmonary disease (COPD) and ILD are similar remains unknown. We aimed to investigate whether REE and its associated factors were similar in patients with COPD and ILD. METHODS: This study included 223 patients (COPD, 102
ILD, 121) who were admitted to our hospital with a diagnosis of COPD or ILD and for whom indirect calorimetry was performed. The measured REE (mREE) was calculated using Weir's formula after indirect calorimetry. Patients with COPD and ILD were classified into two groups by propensity score matching. Multiple regression analysis was used to compare REE between the two groups and examine REE and its associated factors in each group. RESULTS: Body composition and other characteristics differed significantly between the two groups before propensity score matching. Forty-seven patients each were classified into the COPD and ILD groups after propensity score matching. Body mass index was 21.3 ± 3.8 kg/m CONCLUSIONS: FFM plays an important role in determining REE in both diseases, suggesting that REE in patients with COPD and ILD are similar.