Increased energy and/or protein intake improves anthropometry and muscle strength in chronic obstructive pulmonary disease patients: a systematic review with meta-analysis on randomised controlled clinical trials

Compromised nutritional status is associated with a poor prognosis in chronic obstructive pulmonary disease (COPD) patients. However, the impact of nutritional support in this group of patients is controversial. The present study systematically reviewed the effect of energy and or protein supplements or food fortification on anthropometry and muscle strength of COPD patients. We searched MEDLINE (PubMed), EMBASE, Cochrane Library and Scopus for all published randomised clinical trials without language restriction up to May 2021. Three reviewers performed study selection and data extraction independently. We judged the risk of bias by RoB 2 and the certainty of evidence by the GRADE approach. We included thirty-two randomised controlled trials and compiled thirty-one of them (1414 participants) in the random-effects model meta-analyses. Interventions were energy and/or protein oral nutritional supplements or food fortification added to the diet for at least one week. Pooled analysis revealed that nutritional interventions increased body weight (muscle circumference (MD) = 1 center dot 44 kg, 95 % CI 0 center dot 81, 2 center dot 08, I2 = 73 %), lean body mass (standardised mean difference (SMD) = 0 center dot 37; 95 % CI 0 center dot 15, 0 center dot 59, I2 = 46 %), midarm muscle circumference (MD = 0 center dot 29 mm(2), 95 % CI 0 center dot 02, 0 center dot 57, I2 = 0 %), triceps skinfold (MD = 1 center dot 09 mm, 95 % CI 0 center dot 01, 2 center dot 16, I2 = 0 %) and handgrip strength (SMD = 0 center dot 39, 95 % CI 0 center dot 07, 0 center dot 71, I2 = 62 %) compared with control diets. Certainty of evidence ranged from very low to low, and most studies were judged with some concerns or at high risk of bias. This meta-analysis revealed, with limited evidence, that increased protein and/or energy intake positively impacts anthropometric measures and handgrip strength of COPD patients.