Late Breaking Abstract - Dietary nitrate supplementation enhances the benefit of pulmonary rehabilitation in people with COPD

Background: Dietary nitrate supplementation reduces the oxygen cost of peak exercise (Curtis et al, 2015) via improved skeletal muscle blood flow and efficiency of energy metabolism and thus has the potential to augment the effect of exercise training. In COPD, activities of daily living have a disproportionately high oxygen cost. Pulmonary rehabilitation (PR) is fundamental in the management of COPD and dietary nitrate is a possible adjunct to training. Aim: To establish if adjunctive dietary nitrate supplementation enhances the effects of pulmonary rehabilitation in stable COPD. Hypothesis: Dietary nitrate supplementation will enhance the gains in incremental shuttle walk test (ISWT) in the context of PR in COPD patients compared to placebo. Methods: We conducted a multi-centre, double blind, placebo-controlled, parallel group study comparing the effect of 140ml (12.9mmol) of nitrate-rich beetroot juice (BR) with a matched placebo (PL), nitrate-depleted beetroot juice, consumed 3 hours before attending PR sessions only, in patients with COPD (n=122). The PR program consisted of a twice weekly strength and endurance training over 8 weeks with education. The primary outcome was change in ISWT distance. Analysis as intention to treat. Results: 166 patients were recruited, 122 completing the full protocol (female 40%, age 76±11years, BMI 27±7kgm-2, FEV1 %predicted 49±18%, baseline ISWT distance 284.9±152.8m). Nitrate supplementation significantly increased ISWT distance: BR 60m vs. PL 30m (95%CI 10, 40) p=0.008. PR adherence was similar in both groups. Conclusion: Administration of dietary nitrate in association with PR enhances the gains in exercise capacity in COPD patients.