Pulmonary Thromboembolism in Hospitalized Patients with Acute Exacerbation of COPD: Frequency, Predictors, and D-Dimer Performance

Background: Pulmonary thromboembolism (PTE) may mimic or aggravate acute exacerbations of chronic obstructive pulmonary disease (AECOPD). We evaluated the frequency of diagnosed PTE, associated factors, and D-dimer performance in hospitalized patients with AECOPD. Methods: In this single-center retrospective study, 429 consecutive patients hospitalized after presenting at the emergency department with AECOPD between 1 June 2022 and 1 June 2023 were screened; 330 met the eligibility criteria. D-dimer testing was performed at the physician’s discretion in 181 patients, who constituted the primary analysis population, and 87 underwent confirmatory imaging. PTE was confirmed by computed tomography pulmonary angiography or ventilation/perfusion scintigraphy. Results: PTE was diagnosed in 38 patients, corresponding to 21.0% of the D-dimer-tested population and an observed frequency of 11.5% in the overall eligible cohort. In the primary analysis population, D-dimer showed good discrimination for diagnosed PTE (AUC, 0.826; 95% CI, 0.754–0.898; p < 0.001). The exploratory 1053 ng/mL FEU threshold yielded 84.2% sensitivity and 73.4% specificity. In the imaging-confirmed subgroup, the AUC was 0.733 (95% CI, 0.627–0.838), and specificity at this threshold was 55.1%. D-dimer > 1053 ng/mL FEU (adjusted OR, 20.32; 95% CI, 6.80–60.66), female sex (adjusted OR, 4.40; 95% CI, 1.55–12.51), and lower C-reactive protein levels (adjusted OR per 10 mg/L increase, 0.90; 95% CI, 0.83–0.98) were independently associated with diagnosed PTE. Conclusions: Diagnosed PTE was frequent among D-dimer-tested hospitalized patients with AECOPD. Because testing and imaging were physician-directed rather than protocolized, the true prevalence in the overall cohort could not be determined. The 1053 ng/mL FEU threshold should be considered exploratory and requires external validation.