The characteristics of the frequent exacerbator with chronic bronchitis phenotype and non-exacerbator phenotype in patients with chronic obstructive pulmonary disease: a meta-analysis and system review

Abstract

Objective: To investigate the clinical characteristics between the frequent exacerbator with chronic bronchitis (FE-CB) phenotype and the non-exacerbator (NE) phenotype among patients with chronic obstructive pulmonary disease (COPD). Methods: We searched CNKI, Wan fang, Chongqing VIP, China Biology Medicine disc, PubMed, Cochrane Library, and EMBASE databases for relevant studies published as of April 30, 2019. All studies that investigated COPD patients with the FE-CB and NE phenotypes and which qualified the inclusion criteria were included. Cross-Sectional/Prevalence Study Quality recommendations were used to measure methodological quality. RevMan5.3 software was used for meta-analysis. Results: Ten case-control studies (n=8848) were included. Compared with the NE phenotype, patients with the FE-CB phenotype showed significantly lower forced vital capacity percent predicted (FVC%pred) [mean difference (MD) -6.69, 95% confidence interval (CI) -7.73–-5.65, P<0.001, I2=5%], forced expiratory volume in one second percent predicted (FEV1%pred) (MD -8.50, 95% CI -11.36–-5.65, P<0.001, I2=91%), and forced expiratory volume in one second/forced vital capacity (FEV1/FVC) (MD -3.76, 95% CI -4.58–-2.95,P<0.001, I2=0%); in contrast, the quantity of cigarettes smoked (pack-years) (MD 3.09, 95% CI 1.60–4.58, P<0.001, I2=41%), COPD assessment test (CAT) score (MD 5.61, 95% CI 4.62–6.60, P<0.001, I2=80%), modified Medical British Research Council (mMRC) score (MD 0.72, 95% CI 0.63–0.82, P<0.001, I2=57%), exacerbations in previous year (2.65, 95% CI 2.32–2.97, P<0.001, I2=91%), body mass index (BMI), obstruction, dyspnea, exacerbations (BODEx) (MD 1.78, 95% CI 1.28–2.28, P<0.001, I2=91%), I2=34%), and Charlson comorbidity index (MD 0.47, 95% CI 0.37–0.58, P<0.001, I2=0] were significantly higher in patients with FE-CB phenotype. No significant between-group difference was observed with respect to BMI (MD-0.14, 95% CI -0.70–0.42, P=0.62, I2=75%). Conclusion: COPD patients with the FE-CB phenotype had poorer pulmonary function and higher CAT score, the quantity of cigarettes smoked (pack-years), frequency of acute exacerbations, and mMRC scores than those with the NE phenotype.