Effect of statins on pulmonary function in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis of randomized controlled trials

Background: Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease, and its treatment is still controversial. Statins have been proven to have anti-inflammatory and immunomodulatory effects, but their effectiveness in the treatment of COPD is still unclear. We conducted this meta-analysis to more accurately evaluate the therapeutic effect of statins on COPD patients. Methods: Randomized controlled studies published in PubMed, Cochrane Library, Embase, Wiley Online Library, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang databases from inception to July 2022 were retrieved to evaluate the effect of statins on COPD patients. Two evaluators conducted literature screening based on inclusion and exclusion criteria, and conducted a bias risk assessment on them. Meta analysis was conducted using Stata17.0 statistical software. Results: A total of 1,463 patients from 10 studies were included. After statin treatment, the percentage of predicted forced expiratory volume in the first second (FEV1%pred) of COPD patients was improved [weighted mean difference (WMD): 7.89; 95% confidence interval (CI): 7.19-8.60; P<0.05], and the level of the inflammatory factor C-reactive protein (CRP) decreased (WMD: -0.63; 95% CI: -1.84, 0.58; P<0.05). The 6-minute walking distance (6MWD) of patients in the statin treatment group demonstrated a significant benefit (WMD: 26.27; 95% CI: 24.02-28.51; P<0.05). Compared to the placebo control group, statins significantly reduced COPD Assessment Test (CAT) (WMD: -2.45; 95% CI: -3.62, -1.27). Conclusions: Preliminary evidence suggests that statins may have a certain effect on improving lung function, reducing inflammatory factor levels, and improving clinical symptoms in COPD patients. However, due to the quality and quantity limitations of the included studies, these results need to be further verified through a larger, higher quality randomized controlled trial (RCT).