Effect of Orally Administered N-Acetylcysteine on Chronic Bronchitis: A Meta-analysis

Introduction The effect of N-acetylcysteine (NAC) treatment for patients with chronic bronchitis (CB) is controversial. To better understand the role of NAC in CB treatment, we performed a meta-analysis to provide a more accurate estimation of the importance of NAC treatment. Methods PubMed, Embase, and CNKI were systematically searched. The pooled relative risk (RR) and 95% confidence intervals (CI) were calculated using either fixed-effect model or random-effect model based on heterogeneity examination. Statistical analyses were performed using the STATA 12.0 and RevMan 5.2. Results A total of 11 publications with 775 patients who were taking NAC and 789 controls who were taking placebo were judged eligible regarding inclusion criteria. The pooled analysis demonstrated significant evidence that NAC reduced the frequency of CB exacerbations (RR = 0.81, 95% CI 0.69-0.93, P = 0.004). Patients treated with NAC had significant symptom improvement compared with controls (RR = 1.68, 95% CI 1.13-2.52, P = 0.01). NAC did not significantly increase the risk of adverse effects compared with placebo (RR 0.86, 95% CI 0.67-1.09, P = 0.22). Subgroup analysis was carried out to assess the stability of results. No publication bias was detected during analyses. Conclusion There is a role for NAC treatment in the management of CB by reducing symptoms and exacerbations compared with placebo, without increasing the risk of adverse effects. A regular treatment of low dosage (< 1200 mg per day) and a duration of at least 3 months seems to be effective.