Energy expenditure in chronic obstructive pulmonary disease-evaluation of simple measures

Almost 50% of all chronic obstructive pulmonary disease (COPD) patients become underweight. One possible reason for nutritional treatment to fail could be miscalculation of patients' energy requirements. The aim of this study was, therefore, to evaluate simple measures that may be used to assess the energy requirement of COPD patients.

This cross-sectional evaluation study includes 68 COPD patients (42 women). Resting metabolic rate (RMR) was assessed by indirect calorimetry, while total energy expenditure (TEE) was assessed by a 7-day monitoring using the ActiReg. Simple measures to evaluate was body weight (kg) multiplied by 125  kJ (30  kcal), predicted RMR multiplied by 1.7 and two simple questionnaires.

Mean physical activity level (PAL) from the ActiReg was 1.46. Calculation of energy expenditure multiplying body weight with 125  kJ resulted in a TEE of 8614  kJ compared with ActiReg 8317 kJ (P=0.10). To multiply predicted RMR by 1.7 resulted in a statistically significant overestimation of 1335 kJ (P<0.01). Both questionnaires showed a clear 'dose-response' regarding PAL from ActiReg in the different activity categories.

This study shows that simple measures of energy expenditure could, on group level, assess COPD patient's energy needs. However, for individual assessment of energy need, more thorough procedures are necessary.