Determinants of Time to Convalescence among COVID-19 Patients at Millennium COVID-19 Care Center in Ethiopia: A prospective cohort study

Aim: To estimate time to recovery/convalescence and identify determinants among COVID-19 infected patients admitted to Millennium COVID-19 Care Center in Addis Ababa, Ethiopia. Methods: A prospective cohort study was conducted among a randomly selected sample of 360 COVID-19 patients who were on follow up from 2nd June to 5th July 2020. Kaplan Meier plots, median survival times, and Log-rank test were used to describe the data and compare survival distribution between groups. Association between time to recovery/ convalescence and determinants was assessed using the Cox proportional hazard survival model, where hazard ratio, P-value, and 95% CI for hazard ratio were used for testing significance. Results: The mean age of the participants was 32.4 years (+/_ 12.5 years). On admission, 86.9 % had mild COVID-19, 78.6% were asymptomatic and 11.4% of the patients had a history of pre-existing co-morbid illness. The Median time to recovery/ convalescence among the study population was 16 days. The log-rank test shows that having non-mild (moderate and severe) disease, having one or more symptoms at presentation, and presenting with respiratory and constitutional symptoms seems to extend the time needed to achieve recovery. The Final Cox regression result shows that the presence of symptom at presentation was found to be a significant factor that affects time to recovery/ convalescence, the rate of achieving recovery/ convalescence among symptomatic patients was 44% lower than patients who were asymptomatic at presentation (HR= 0.560, 95% CI= 0.322-0.975, p-value=0.040). Conclusions: Presence of symptom was found to be associated with delayed viral clearance. This implies symptomatic patients are more likely to be infectious because of the prolonged viral shedding in addition to the presence of a more concentrated virus in the upper respiratory tract that enhances the transmission. Therefore, attention should be given in the isolation and treatment practice of COVID-19 patients with regard to presence of symptom.