COPD exacerbation purulence status and its association with pulmonary embolism: a systematic review with meta-analysis

Background: Diagnosing pulmonary embolism (PE) in patients with acute exacerbation of COPD (AECOPD) is challenging. Finding predictors of PE could help improve diagnostic management of patients with AECOPD. The aim was to evaluate the association between AECOPD purulence status and the presence of PE. Methods: A systematic review with meta-analysis was conducted. Medline, Embase and CENTRAL were searched from inception to April 2024 for randomised trials, cohort or cross-sectional studies reporting on the prevalence of PE according to AECOPD purulence status. Relative risks with 95% confidence intervals of PE according to AECOPD purulence status and pooled proportions of PE with their 95% confidence intervals were calculated according to AECOPD purulence status. Results: From 7059 citations identified, 14 studies (5056 participants) were included. The prevalence of PE varied between 0.4% and 33.2% across studies. The relative risk of PE was not statistically significantly lower in patients with purulent AECOPD compared to patients with nonpurulent/unknown aetiology AECOPD (relative risk 0.64, 95% CI 0.26-1.55; I²=88.0%). The pooled proportion of PE was 7.3% (95% CI 2.4-14.7%; I²=94.7%) and 13.3% (95% CI 8.0-19.7%; I²=96.0%) in studies including patients with purulent AECOPD and nonpurulent/unknown aetiology AECOPD, respectively. Conclusion: The relative risk of PE was lower, but not statistically significant, in patients with purulent AECOPD compared to patients with nonpurulent/unknown aetiology AECOPD. Further studies are needed to confirm the association between PE and AECOPD purulence status and to assess its potential role in predicting PE.