Association Between C-Reactive Protein and Albumin Ratios and Risk of Mortality in Patients with Chronic Obstructive Pulmonary Disease

Abstract

Purpose

This study was to evaluate the association between C-reactive protein (CRP) to albumin (ALB) ratio (CAR) and the risk of mortality in patients with chronic obstructive pulmonary disease (COPD).

Methods

In this retrospective cohort study, clinical data were extracted from the National Institutes of Health National Health and Nutrition Examination Survey (NHANES) database between 2007 and 2010. Cox proportional hazard regressions were performed to assess the association between CAR and 5-year mortality in COPD patients. Subgroup analyses were applied to identify the consistency of the association based on the severity of COPD, gender, body mass index (BMI), smoking status, cardiovascular disease (CVD), and chronic kidney disease (CKD), and diabetes. The area under the curve (AUC) of the receiver operator characteristic (ROC) curve analysis was used to evaluate the predictive performance of CAR.

Results

A total of 1210 COPD patients were included, of which 110 COPD patients (9.09%) had 5-year mortality. The mean follow-up was 57.76 (0.33) months. A higher CAR was associated with an increased risk of 5-year mortality in COPD patients [hazard ratio (HR): 1.94, 95% confidence interval (CI): 1.07 to 3.50, P =0.029)]. Subgroup analysis showed that the association between CAR and mortality was especially suitable for COPD patients with mild COPD, in COPD patients who were still smoking, in COPD patients with BMI <=29.9 kg/m², in COPD patients who were without CVD, in COPD patients who were without diabetes, and COPD patients who were without CKD. The AUCs of CAR for predicting 1-year, 3-year, and 5-year mortality in COPD patients were 0.735, 0.615, and 0.608, respectively.

Conclusion

CAR is strongly correlated with mortality in patients with COPD and CAR could be served as a prognostic biomarker for patients with COPD. This study may provide a promising prognostic biomarker for risk stratification and clinical management of patients with COPD.

Keywords:

• C-reactive protein
• albumin
• mortality
• chronic obstructive pulmonary disease

Ethics Approval and Informed Consent

The requirement of ethical approval for this was waived by the Institutional Review Board of The Affiliated Changzhou Second People’s Hospital of Nanjing Medical University, because the data was accessed from NHANES (a publicly available database). The need for written informed consent was waived by the Institutional Review Board of The Affiliated Changzhou Second People’s Hospital of Nanjing Medical University due to retrospective nature of the study.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This study received no funding.