Does chronic obstructive pulmonary disease relate to poor prognosis in patients with lung cancer?: A meta-analysis

Nowadays, there is growing recognition that chronic obstructive pulmonary disease (COPD) may have influence on lung cancer. However, coexisted COPD related to prognosis of lung cancer is still elusive. We conducted this meta-analysis to examine the association between COPD and 5-year overall survival (OS) and postoperative pulmonary complications of patients with lung cancer. A comprehensive computer-based online search was conducted using PubMed, Embase, Medline, and the Cochrane Library for articles published before September 30, 2017. We identified 29 eligible studies, which included 70,111 patients in the related literature. Twenty-two of the 29 studies provided hazard ratio for OS (1.18, 95% confidence interval: 1.11-1.25; P