Comparative Efficacy of Nutritional Supplements in Modulating Lung Function and Exercise Capacity in COPD Patients: A Network Meta-Analysis

Abstract

Objective: To compare the effects of nutritional supplements on lung function and exercise tolerance in chronic obstructive pulmonary disease (COPD).

Methods: We searched PubMed, Embase, Cochrane Library, and Web of Science for randomized controlled trials (RCTs) on nutritional supplements in COPD patients, with the search ending December 31, 2023. Two authors independently screened studies, extracted data, and assessed quality using the Cochrane risk of bias tool. Data were analyzed using RevMan 5.4 and R 4.2.3.

Results: Forty-eight studies with 2481 COPD patients were included. Network meta-analysis showed six supplements significantly improved the 6-minute walk distance (6MWD) (all p<0.05), with the top three being: Coenzyme Q10+ Creatine [MD=63, 95% CI (36, 90)], L-carnitine [MD=53, 95% CI (24, 82)], and anabolic steroids [MD=44, 95% CI (7.1, 82)]. Four supplements improved FEV₁%(all p<0.05): nanocurcumin [MD=13, 95% CI (7.7, 18)], Vitamin D [MD=7.5, 95% CI (5.1, 9.9)], probiotics [MD=7.1, 95% CI (5.2, 9.1)] and BSO [MD=4.9, 95% CI (1.6, 8.3)]. In pairwise comparisons, nanocurcumin outperformed BSO and Probiotics. Nanocurcumin [MD=12, 95% CI (4.6, 19), p<0.05] improved FEV₁/FVC, and nitrate [MD=26, 95% CI (9.7, 42), p<0.05] was effective for the Incremental Shuttle Walk Test (ISWT). Traditional Chinese Medicine (TCM) products [MD=-1.3, 95% CI (-1.9, -0.67)], melatonin (MLT) [MD=-0.9, 95% CI (-1.6, -0.21)] and Calcitriol [MD=-0.66, 95% CI (-0.93, -0.39)] improved the modified Medical Research Council(mMRC) dyspnea score (all p<0.05), with comparable efficacy among them.

Conclusion: Nutritional supplements improve lung function and exercise endurance in COPD. Coenzyme Q10+Creatine is most effective for endurance, while Nanocurcumin has the greatest impact on lung function.

Keywords: chronic obstructive pulmonary disease; exercise endurance; lung function; network meta-analysis; nutritional supplements.

Figure 1

PRISMA flow diagram of the study process. PRISMA: Preferred Reporting Items for Systematic review and Meta-analysis. PRISMA figure adapted from Liberati A, Altman D, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration. Journal of clinical epidemiology. 2009;62(10). Creative Commons.

Figure 2

Risk of Bias for all studies included in this network Meta-analysis.

Figure 3

Meta analysis of 6MWD ((a) Network plot: (b) area under the cumulative probability curve: (c) forest plot) The number on each edge indicates the trials included in the direct comparison.

Figure 4

Meta analysis of FEV₁% ((a) Network plot: (b) area under the cumulative probability curve: (c) forest plot) The number on each edge indicates the trials included in the direct comparison.

Figure 5

Meta analysis of FEV₁/FVC ((a) Network plot: (b) area under the cumulative probability curve: (c) forest plot) The number on each edge indicates the trials included in the direct comparison.

Figure 6

Meta analysis of mMRC ((a) Network plot: (b) area under the cumulative probability curve: (c) forest plot) The number on each edge indicates the trials included in the direct comparison.

Figure 7

Meta analysis of ISWT ((a): Network plot: (b): area under the cumulative probability curve: (c): forest plot) The number on each edge indicates the trials included in the direct comparison.