Danish evidence-based clinical guideline for use of nutritional support in pulmonary rehabilitation of undernourished patients with stable COPD

Background and aims: Disease-related under-nutrition is a common problem in individuals with COPD. The rationale for nutritional support in pulmonary rehabilitation therefore seems obvious. However there is limited evidence regarding the patient-relevant outcomes i.e. activities of daily living (ADL) or quality of life. Therefore the topic was included in The Danish Health and Medicines Authority's development of an evidence-based clinical guideline for rehabilitation of patients with stable COPD. Methods: The methods were specified by The Danish Health and Medicines Authority as part of a standardized approach to evidence-based national clinical practice guidelines. They included formulation of a PICO with pre-defined criteria for the Population, Intervention, Control and Outcomes. Existing guidelines or systematic reviews were used after assessment using the AGREE II tool or AMSTAR, if possible. We identified primary studies by means of a systematic literature search (July to December 2013), and any identified studies were then quality assessed using the Cochrane risk of bias tool and the GRADE approach. The extracted data on our pre-defined outcomes were summarized in meta-analyses when possible, or meta-analyses from existing guidelines or systematic reviews were adapted. The results were used for labeling and wording of the recommendations. Results: Data from 12 randomized controlled trials were included in a systematic review, which formed the basis for our recommendations as no new primary studies had been published. There were evidence of moderate quality that nutritional support for undernourished patients with COPD lead to a weight gain of 1.7 kg (95% confidence interval: 1.3 to 2.2 kg), but the effect was quantified as a mean change from baseline, which is less reliable. There were evidence of moderate quality that nutritional therapy does not increase in the 6 minute walking distance of 13 m (95% confidence interval: -27 to 54 m) when results in the intervention and control groups were compared at 9-16 weeks of follow-up. There was evidence of very low quality for an increase in lean body mass. The studies did not demonstrate an effect on either quality of life or ADL in patients with COPD. Some pre-defined outcomes (adverse events, hospital admissions and mortality) were not quantified. Conclusion: The evidence base for nutritional supplementation in rehabilitation of COPD patients is weak and any effect was limited to surrogate markers, such as increased weight and lean body mass, while an effect could not be seen on patient-relevant outcomes such as quality of life or activities of daily living. The intervention was given a weak recommendation.