Investigating the role of uric acid and uric acid-to-creatinine ratio as a predictive factor of chronic obstructive pulmonary disease exacerbation in 2019

Introduction: Serum uric acid has been suggested as an independent marker of oxidative metabolism in chronic obstructive pulmonary disease (COPD), a disease with significant social, health, and economic burden. Therefore, we aimed to investigate the role of this factor in COPD exacerbation.

Methods: We investigated 20- to 70-year-old patients who were admitted due to COPD exacerbation (acute phase) or presented to the pulmonary clinic for follow-up (non-acute phase). Correlation of uric acid and uric acid-to-creatinine ratio (UCR) with multiple factors and their predictive performance for more exacerbations and acute phase of COPD was investigated (receiver operating characteristic [ROC] analysis).

Results: Overall, 63 patients were enrolled in this study, of whom 79.4% were men. Acute-phase group encompassed 79.4% of the population with a greater rate of heavy smoking and average exacerbation in a year (p-value = 0.009 and <0.001). The mean of uric acid and UCR was 5.6 (SD, 2.35) and 4.4 (SD, 1.9) in the total population, respectively, and were significantly higher in the acute phase and patients with frequent exacerbations (FE ≥ 3 exacerbations a year), p-value <0.05. The area under the curve (AUC) of ROC analysis showed a high performance of uric acid and UCR for predicting acute phase (0.84 [95%CI, 0.73-0.96] and 0.86 [0.74-0.98]), FE (0.72 [0.60-0.85] and 0.75 [0.63-0.87]), and FE among acute-phase patients (AUC, 0.63 [0.46-0.79] and 0.66 [0.50-0.81], respectively).

Conclusion: Uric acid and UCR could be invaluable predictors of frequent exacerbation and the acute phase of COPD. Therefore, they might be applicable in evaluating the severity and progress of the disease.