Nutritional supplementation for stable chronic obstructive pulmonary disease
Abstract
Background
Low body weight in patients with chronic obstructive pulmonary disease (COPD) is associated with an impaired pulmonary status, reduced diaphragmatic mass, lower exercise capacity and higher mortality rate when compared to adequately nourished individuals with this disease. Nutritional support may therefore be a useful part of their comprehensive care.
Objectives
To conduct a systematic review of randomised controlled trials (RCTs) to clarify whether nutritional supplementation (caloric supplementation for at least 2 weeks) improved anthropometric measures, pulmonary function, respiratory muscle strength and functional exercise capacity in patients with stable COPD.
Search methods
Randomized controlled trials (RCTs) were identified from the Cochrane Airways Group register of RCTs, a hand‐search of abstracts presented at international meetings and consultation with experts. Searches are current as of June 2006.
Selection criteria
Two reviewers independently selected trials for inclusion, assessed quality and extracted the data.
Data collection and analysis
Within each trial and for each outcome, we calculated an effect size. The effect sizes were then pooled by a random‐effects model. Homogeneity among the effect sizes was also tested.
Main results
Fourteen studies recruiting 487 participants met the inclusion criteria. Nine papers were considered as high quality. Two studies were double‐blinded. For each of the outcomes studied, the effect of nutritional support was small: the 95% confidence intervals around the pooled effect sizes all included zero. The effect of nutritional support was homogeneous across studies.
Authors' conclusions
Nutritional support had no significant effect on anthropometric measures, lung function or exercise capacity in patients with stable COPD. Although some quality of life indices gave significant findings, these results were from a single small unblinded study and restricted to certain domains of health status measurements. More work in this particular area is needed to establish whether supplementation can lead to subjective benefits in quality of life.
PICOs
Plain language summary
Nutritional supplementation for stable chronic obstructive pulmonary disease
Low body weight is common in people with chronic obstructive pulmonary disease (COPD). It can impair their heart and lung function and reduce their ability to exercise and recover. Some degree of malnutrition is common in people with COPD but it is unclear whether this is the cause of their deterioration, or just part of the progress of the disease. The review of trials found no evidence that simple nutritional supplementation makes a significant difference to people with COPD. More research is needed.
