Prevalence and risk factors of pulmonary embolism in acute exacerbation of chronic obstructive pulmonary disease and its impact on outcomes: a systematic review and meta-analysis.

OBJECTIVE The current study aimed to pool data for the prevalence of pulmonary embolism (PE) in acute exacerbation of chronic obstructive pulmonary disease (AE-COPD). We also aimed to assess the risk factors of PE and its impact on the outcomes of AE-COPD. MATERIALS AND METHODS PubMed, Embase, and CENTRAL databases were searched up to 1st January 2021 for prospective, retrospective, and cross-sectional studies reporting the prevalence of PE in AE-COPD based on computed tomography (CT) data. RESULTS Sixteen studies were included. Pooled data of 5035 patients indicated the prevalence of PE in AE-COPD to be 12.9% (95% CI: 8.9%-18.4%). In studies wherein, all patients underwent CT the prevalence was 19.4% (95% CI: 13.4%-27.4%). On the other hand, the prevalence of PE was 7.8% (95% CI: 3.7%-15.7%) in studies where CT was carried out only after screening patients based on study-specific diagnostic protocol. Multiple studies indicated that recent immobilization, increased D-dimer levels, lower limb edema, older age and the concomitant presence of deep vein thrombosis were independent risk factors for PE in AE-COPD. Pooled analysis indicated that PE was associated with a significantly increased risk of mortality (OR: 3.21 95% CI: 1.86, 5.54 I2=52% p<0.0001) and longer ICU/hospital stay (MD: 3.26 95% CI: 1.93, 4.58 I2=0% p<0.00001) in AE-COPD. CONCLUSIONS The prevalence of PE in AE-COPD is estimated to be 12.9%. This figure, however, varies based on the PE workup protocol. Higher prevalence (19.4%) was noted when all patients underwent CT as compared to when a study-specific diagnostic protocol was followed (7.8%). Recent immobilization, increased D-dimer levels, lower limb edema, older age and the concomitant presence of deep vein thrombosis are important independent risk factors for PE in patients with AE-COPD. Patients diagnosed with PE have increased mortality and longer ICU/hospital stay as compared to non-PE patients.