Systematic review and meta-analysis of the efficacy of N-acetylcysteine in the treatment of acute exacerbation of chronic obstructive pulmonary disease

Background: Whether N-acetylcysteine (NAC) therapy can promote the improvement of clinical symptoms and lung function in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) has not been verified by large-scale randomized controlled trials, only a few small sample studies. Methods: English databases were searched using a combination of the following terms: "chronic obstructive pulmonary disease", "acute exacerbation of chronic obstructive pulmonary disease", and "N-acetylcysteine". Studies examining NAC in the treatment of AECOPD were screened, so as to be a reference for the experimental group. Meta-analysis was performed using RevMan 5.3 software (Cochrane, Northern Europe), with a total of 15 included literatures. Results: The heterogeneity test of improvement rate showed Chi(2)=1.89, df=7, I-2=0% <50%, and P=0.97 (>0.01); the risk rate was 1.09, the 95% confidence interval (CI) was (1.04-1.14), Z=3.93, and P<0.0001. The heterogeneity test of forced expiratory volume in the first second (FEV1) showed that Tau(2)=63.39, Chi(2)=118.66, df=9, I-2=92% >50%, and P=0.88 (<0.0001); the mean difference was 30.63 (95% CI: 25.48-35.78), Z=11.65, and P<0.0001. The results of the heterogeneity test of forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) showed that Tau(2)=60.03, Chi(2)=74.09, df=5, I-2=93% >50%, and P<0.0001; the mean difference was 30.42 (95% CI: 24.00-36.85), Z=9.28, and P<0.0001. The heterogeneity test for glutathione sulfur transferase (GSH-ST) activity showed that Tau(2)=4.12, Chi(2)=58.12, df=5, I-2=91% >50%, and P<0.0001; the mean difference was 3.10 (95% CI: 1.38-4.82), Z=3.63, and P=0.0004. Conclusions: Our meta-analysis confirmed that NAC could promote the symptom improvement rate of patients with AECOPD, improve lung function in FEV1 and FEV1/FVC, and enhance the body's antioxidant capacity.