Estimation of Length of In-Hospital Stay Using Demographic Data of the First 1000 COVID-19 Patients in Singapore

COVID-19 has been declared as a global pandemic by the World Health Organization (WHO) on March 11, 2020. In this paper, we investigate various aspects of the clinical recovery of the first 1000 COVID-19 patients in Singapore, spanning from January 23 to April 01, 2020. This data consists of 245 clinically recovered patients. The first part of the paper studies the descriptive statistics and the influence of demographic parameters, namely age and gender, in the clinical recovery-period of COVID-19 patients. The second part of the paper is on identifying the distribution of the length of the in-hospital stay (LOS) for the patients. Based on the hospital protocols followed in Singapore, this is equivalent to the virus shedding period. We determine a periodization based on critical changes in the transmission model. As expected, the overall recovery rate has reduced drastically during the exponential increase of incidences. However, our work on identifying parameters for a regression model shows that there is a shift in the age-group of incidences to the younger population, and the recovery-period of the younger population is considerably lower. Here, we have estimated the most likely length of in-hospital stay to be 9 days, as opposed to 15 or 20 days. Overall, the prognosis of COVID-19 indicates a reduction in length of in-hospital stay owing to the government-mandated practices of restricted mobility of the older population and aggressive contact tracing.