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

Abstract

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 (PaCO₂), 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; PaCO₂: 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.

Keywords:

• AECOPD
• chronic obstructive pulmonary diseases
• D-dimer
• mortality
• prognosis

Acknowledgments

This study was supported by The National Key Technology R&D Program of the 12th National Five-year Development Plan 2012BAI05B01 (P.R.), the Medical Science and Technology Research Fund of Guangdong Province (A2016265), and the scientific research fund of the health department of Guangxi Zhuang Autonomous Region (Z2012248).

Author contributions

Guoping Hu, Yankui Wu, and Pixin Ran conceived the idea for this report. Guoping Hu, Yankui Wu, and Yumin Zhou wrote the first draft of the article. Guoping Hu, Yankui Wu, Yumin Zhou, GongYong Peng, Zelong Wu, Liping Wei, Yuqun Li, Weiqiang Liang, and Pixin Ran contributed to the final version. Guoping Hu, Zelong Wu, Liping Wei, Yuqun Li, and Weiqiang Liang collected data for the study. Guoping Hu and Yumin Zhou performed the statistical analyses. Guoping Hu and Yankui Wu are co-first authors. All authors contributed toward data analysis, drafting and revising the paper and agree to be accountable for all aspects of the work.

Disclosure

All authors report that there is no potential conflict of interest with any companies/organizations. Yankui Wu is the wife of Guoping Hu. All the other authors are from a different family.