The Relationship between Serum Uric Acid and Severity of Chronic Obstructive Pulmonary Disease (COPD)

Introduction: Some evidence exists about the possible relationship between the serum uric acid (UA) and exacerbation of the chronic obstructive pulmonary disease (COPD). Present study intended to compare the COPD-related variables and the one-year outcome between the two groups of patients with the high and low UA. Material and Methods: This cohort study consisted of 112 patients with COPD exacerbation. The participants were categorized into low (i.e., <6.5 mg/dL UA, 61 patients) and high (i.e., ≥6.5 mg/dl UA, 51 patients) groups. The variables including: Global initiative for Obstructive Lung Disease (GOLD) classification, oxygen saturation, PCO2, FEV1 (forced expiratory volume in 1 second), trans-thoracic 2D echocardiographic indices, and serum BUN (blood urea nitrogen) and creatinine levels were recorded. Afterwards, the patients were followed up for one year and some other variables such as taking oral antibiotic for respiratory infections, admission to hospital or ICU due to COPD exacerbation, and survival were documented monthly. Results: The mean serum level of creatinine was significantly higher in the high UA group (1.1±0.4 mg/dL) than the low UA group (1.01±0.1 mg/dL) (P=0.02). No significant difference was observed between the two groups regarding the GOLD classification, FEV1, oxygen saturation, pCO2, and echocardiographic indices. In the one-year follow-up, 42 cases (82.4%) of the high UA group and 39 patients (63.9%) of the low UA group reported taking oral antibiotics, which was indicative of a significant difference (P=0.03). Hospital admission was likewise significantly higher in the high UA group (30 patients, 58.8%) than in the low UA group (23 cases, 37.7%) (P= 0.03). Conclusion: Those patients with the UA level of ≥ 6.5 mg/dL experienced more hospital admission and were more likely to take oral antibiotics for respiratory infections during a year. However, UA did not correlate with FEV1 or COPD severity.