Utility of Serum Uric Acid and Serum Uric Acid to Creatinine Ratio in the Assessment of Severity in Acute Exacerbation of Chronic Obstructive Pulmonary Disease

Abstract

Background: Exacerbations of Chronic Obstructive Pulmonary Disease (COPD) lead to multiple hospital admissions, longer hospital stays as well as increased morbidity and mortality. Currently, no effective biomarker exists that can assess disease severity and activity in acute conditions. Serum uric acid is increased in the hypoxic state as well as in systemic inflammation like COPD. Objective: To determine the utility of serum uric acid and serum uric acid to creatinine ratio to assess the severity of acute exacerbation of COPD. Methods: This cross-sectional study was conducted in the Department of Respiratory Medicine, NIDCH, Mohakhali, Dhaka from June 2020 to August 2021. A total of 139 diagnosed COPD patients (both acute exacerbation of COPD and stable COPD) were enrolled. Blood sample was collected for serum uric acid, serum creatinine and arterial blood gas analysis. Results were obtained from the student t- test, ANOVA, Chi-square tests. ROC curve was prepared to see the efficacy of uric acid and uric acid to creatinine ratio in the assessment of severity. Results: Among 139 patients, 48 patients had stable COPD and 91 patients had acute exacerbations; among AECOPD patients, 50(54.9%) were labeled as severe and 41 (45.1%) were non-severe based on their ABG findings. Serum uric acid to creatinine ratio and uric acid levels were found to be significantly higher in exacerbation patients. Serum uric acid to creatinine ratio was found to be significantly higher in severe exacerbation patients. The area under the ROC curve of serum uric acid to creatinine ratio and serum uric acid was 0.654 and 0.610 in assessing the severity of AECOPD. The sensitivity, specificity, PPV and NPV of serum uric acid were 0.660, 0.610, 0.853 and 0.595 in assessing the severity of acute exacerbation at a cut off value of 6.85. The sensitivity, specificity, PPV and NPV of serum uric acid to creatinine ratio were 0.800, 0.537, 0.678 and 0.688 in assessing the severity of acute exacerbation at cut off value of 6.32. Conclusion: In the absence of spirometry and arterial blood gas analysis, serum uric acid and serum uric acid to serum creatinine ratio cannot be used to assess the severity of AECOPD. Chest Heart J. 2023; 47(1) : 49-57