Introduction
- Chronic obstructive pulmonary disease (COPD) is a leading cause of death in both the United States and world-wide. COPD is described by the American Thoracic Society as a slowly progressive lung disease that is characterized by airflow limitation and obstruction.
- Although COPD affects the lungs, it also produces significant systemic consequences. Adults who are diagnosed with COPD often have other comorbidities and especially in the elderly are particularly vulnerable to the effects of smoking, poor diet and inactivity. COPD may be accompanied by weight loss, nutritional abnormalities and loss of skeletal muscle and/or function.
- The primary goals of medical nutrition therapy (MNT) for people with COPD are to achieve and maintain appropriate body weight and composition, maximize pulmonary status, reduce mortality, and improve quality of life (QOL).
Nutrition Assessment
COPD: Assessment of Energy Intake
- The registered dietitian nutritionist (RDN) should assess the energy intake of adults with COPD. Evidence suggests there was improvement in dyspnea scores with higher energy intakes. In addition, less robust evidence supported a beneficial relationship with functional status, healthcare utilization or duration of illness. (Fair/Imperative)
COPD: Assessment of Body Weight Status
- The RDN should assess body mass index (BMI) or other measures of body weight in adults with COPD. Strong evidence suggests an association between body weight status and mortality in adults with COPD. The lowest BMI groups had higher mortality rates when compared to higher BMI groups. Furthermore, a BMI classification of approximately 25.0 kg/m2 to 29.99 kg/m2 appeared to lower the risk of mortality when compared to both higher and lower BMI classifications. In unadjusted results, there was fair evidence of a positive association between BMI and FEV1 percentage predicted. An increasing BMI was also shown to reduce declines in FEV1 percentage predicted over time in a longitudinal study. (Strong/Imperative)
COPD: Estimating Resting Metabolic Rate (RMR)
- To calculate RMR in adults with COPD, the RDN may use either the World Health Organization [WHO (including height)] equation or the Harris-Benedict equation (HBE). If body composition is known (fat-free mass, body fat), the RDN may use the Westerterp equation. Limited evidence showed that the Westerterp equation has a prediction accuracy rate of 68%, followed by the WHO (including height: 63%) and Harris-Benedict (61%) equations. (Weak/Conditional)
COPD: Estimating Total Energy Expenditure (TEE)
- To calculate TEE in non-obese adults with COPD, the RDN may use 30 kcal per kg body weight (BW) to estimate energy needs. Limited evidence suggests that 30 kcal per kg body weight (in non-obese adults with COPD) produced an estimate that was not different from measured values on average but whose variability was wide, indicating that estimation errors might be common and large. (Weak/Imperative)
COPD: Assessment of Serum 25(OH)D Status
- The RDN should assess serum 25(OH)D levels in adults with COPD as part of a routine nutrition assessment. Evidence from 60% of studies reviewed found positive associations between serum 25(OH)D and lung function measures. (Fair/Imperative)
COPD: Assessment of Exacerbations
- If an adult with COPD is having two or more exacerbations per year, the RDN should assess 25(OH)D levels. Evidence from adults with COPD with baseline serum 25(OH)D levels ≤10ng per ml, showed that vitamin D supplementation decreased exacerbations. (Fair/Conditional)
