Association of Serum Calcium and Serum Uric Acid Level with Inflammatory Markers to Predict the Outcome of COVID-19 Infection: A Retrospective Study

Introduction: Novel Coronavirus Disease 2019 (COVID-19) is an acute respiratory disease and the severity of COVID-19 is highly variable, ranging from asymptomatic infection to lifethreatening disease. Therefore, biomarkers are required to assess the prognosis of the disease at the earliest. Aim: To determine the correlation of serum calcium and serum uric acid levels with inflammatory markers of COVID-19 infection and also to assess serum calcium and serum uric acid levels in predicting the outcome of COVID-19 infection. Materials and Methods: A retrospective study was conducted in Adichunchanagiri Institute of Medical Sciences, B.G Nagara, Karnataka, India from 1st April 2021 to 30th June 2021. Out of 483 COVID-19 infected patients admitted during the study period, data of 136 patients, investigated for serum calcium and serum uric acid levels were collected from medical records. Patients were categorised into survived and non survived group based on the outcome. Descriptive statistics, Analysis of Variance (ANOVA) test, Student’s t-test were applied. Receiver Operating Characteristic (ROC) curve was used in predicting the outcome of COVID-19 infection. Results: Of the 136 COVID-19 positive patients, 87 were male and 49 were female patients. Mean age of non survived was significantly higher (59.19±12.6 years) as compared to survived patients (44.44±13.35 years). Further, Random Blood Sugar (RBS), C-Reactive Protein (CRP), Lactate Dehydrogenase (LDH) and D-dimer values were significantly higher among non survived patients (233±135.37 mg/dL, 9.92±3.93 mg/L, 422.88±191.51 IU/L and 586.19±258.9 ng/mL, respectively) as compared to survived patients. Significant positive correlation was found between serum uric acid levels with LDH (r-value=0.231; p-value=0.007). Whereas, serum calcium showed negative correlation with CRP (r-value=-0.55; p-value=0.526) and D-dimer (r-value=-0.052; p-value=0.551). The ROC curve analysis showed that area under curve for serum uric acid level (0.530) was more as compared to serum calcium (0.460). Conclusion: Serum uric acid is emerged as a better biomarker towards the prediction of outcome of patients. Early evaluation of serum calcium levels and serum uric acids could aid in predicting the outcome of the disease.