Prognostic role of D-dimer for in-hospital and 1-year mortality in exacerbations of COPD

BACKGROUND AND OBJECTIVE: Serum D-dimer is elevated in respiratory disease. The objective of our study was to investigate the effect of D-dimer on in-hospital and 1-year mortality after acute exacerbations of chronic obstructive pulmonary disease (AECOPD). METHODS: Upon admission, we measured 343 AECOPD patients’ serum D-dimer levels and arterial blood gas analysis, and recorded their clinical characteristics. The level of D-dimer that discriminated survivors and non-survivors was determined using a receiver operator curve (ROC). The risk factors for in-hospital mortality were identified through univariate analysis and multiple logistic regression analyses. To evaluate the predictive role of D-dimer for 1-year mortality, univariate and multivariate Cox regression analyses were performed. RESULTS: In all, 28 patients died, and 315 patients survived in the in-hospital period. The group of dead patients had lower pH levels (7.35±0.11 vs 7.39±0.05, P<0.0001), higher D-dimer, arterial carbon dioxide tension (PaCO(2)), C-reactive protein (CRP), and blood urea nitrogen (BUN) levels (D-dimer 2,244.9±2,310.7 vs 768.2±1,078.4 µg/L, P<0.0001; PaCO(2): 58.8±29.7 vs 46.1±27.0 mmHg, P=0.018; CRP: 81.5±66, P=0.001; BUN: 10.20±6.87 vs 6.15±3.15 mmol/L, P<0.0001), and lower hemoglobin levels (118.6±29.4 vs 128.3±18.2 g/L, P=0.001). The areas under the ROC curves of D-dimer for in-hospital death were 0.748 (95% confidence interval (CI): 0.641–0.854). D-dimer ≥985 ng/L was a risk factor for in-hospital mortality (relative risk =6.51; 95% CI 3.06–13.83). Multivariate logistic regression analysis also showed that D-dimer ≥985 ng/L and heart failure were independent risk factors for in-hospital mortality. Both univariate and multivariate Cox regression analyses showed that D-dimer ≥985 ng/L was an independent risk factor for 1-year death (hazard ratio (HR) 3.48, 95% CI 2.07–5.85 for the univariate analysis; and HR 1.96, 95% CI 1.05–3.65 for the multivariate analysis). CONCLUSION: D-dimer was a strong and independent risk factor for in-hospital and 1-year death for AECOPD patients.