High-dose N-acetylcysteine for long-term, regular treatment of early-stage chronic obstructive pulmonary disease (GOLD I-II): study protocol for a multicenter, double-blinded, parallel-group, randomized controlled trial in China

Introduction: The presence of increased oxidative stress and airway inflammation has been proven in subjects with chronic obstructive pulmonary disease (COPD). Several studies have demonstrated that drugs with antioxidant and anti-inflammatory properties such as N-acetylcysteine (NAC) can reduce the rate of exacerbations in patients with COPD. However, the beneficial effects of NAC in early-stage COPD are minimally discussed. We are investigating whether high-dose NAC has therapeutic effects in Chinese patients with early-stage COPD.

Method and analysis: A randomized, double-blinded, placebo-controlled, parallel-group, multicenter clinical trial is evaluating the efficacy and safety of NAC for the long-term treatment of patients with early-stage COPD at 24 centers in China. Subjects aged 40-80 years and recruited by physicians or researchers with special training will be randomized to either NAC 600 mg twice daily group or matching placebo group for 2 years. Measurements will include forced expiratory volume in 1 s (FEV₁), the number of COPD exacerbations, health-related quality, and pharmacoeconomic analysis.

Discussion: Currently, there are no randomized controlled trials with high-dose N-acetylcysteine (600 mg twice daily) for patients with mild-to-moderate COPD (GOLD I-II). We designed this multicenter randomized controlled trial (RCT) to assess the effectiveness, safety, and cost-effectiveness of long-term treatment with high-dose N-acetylcysteine. The results of this trial may guide clinical practice and change the standard of early COPD management.

Trial registration: Chinese Clinical Trial Registry ChiCTR-IIR-17012604 . Registered on 07 September 2017.