Clinical characteristics of Covid-19 patients with re-positive test results: an observational study

Background: With coronavirus disease 2019 (Covid-19) ravaging the global, concern has been aroused whether discharged Covid-19 patients with reappeared positive nucleic acid test results are infected again. Objective: To analyze the clinical characteristics of discharged Covid-19 patients with reappeared positive nucleic acid test results and to track clinical outcomes of them. Methods: We extracted clinical data on 938 Covid-19 patients from Wuhan Union Hospital (West Branch), and we obtained information about residual symptoms and nucleic acid tests after discharge through follow-up study. We evaluated the relationship of clinical characteristics and reappeared positive results. Each patient had at least 44 days of follow-up. Results: Of 938 discharged patients, a total of 58 (6.2%) had reappeared positive nucleic acid test results and 880 remain negative. Among patients over the age of 50, the factors we found to be associated with re-positive results were coronary artery disease (14.1%, vs. 5.5% among those without coronary artery disease; odds ratio, 2.81; 95% confidence interval [CI], 1.28 to 6.15), and hypertension (9.5%, vs. 4.9% among those without hypertension; odds ratio, 2.05; 95% CI, 1.10 to 3.82). As of May 11, 2020, 54 (93.1%) re-positive patients turned negative again while two patients remained positive, and two patients was lost to the second follow-up. Conclusion: Coexisting diseases including coronary artery disease and hypertension were substantial risk factors for re-positive outcomes among patients over 50. And most re-positive patients tended to return negative eventually.