Survival Time, Mortality Rate, and Predicted Deaths for COVID-19 In-Patients in the United Kingdom

Abstract

Background: Public Health England (PHE) published data for COVID-19 since the start of the outbreak in the United Kingdom (UK). The aim of this study was to estimate survival time, mortality rate, and predicted deaths for COVID-19 in-patients. Methods: The PHE dataset contained 88,621 and 11,329 cumulative counts for COVID-19 cases and deaths. Linear regression was utilised to generate standard curves for cumulative COVID-19 deaths against cumulative COVID-19 cases reported on the nth previous day (day -n standard curves). Estimates for predicted deaths were assessed against reported deaths using linear regression; the precision (1/standard error) of these estimates indicated the survival time. The slope of the corresponding standard curve indicated the case mortality rate. Correlations between data were assessed using Spearman correlation coefficients. Joinpoint regression analysis identified significant changes in daily percentage change (DPC) for predicted deaths. Mortality rate and DPC were utilised to extend predicted COVID-19 cases and deaths to 30 Apr 2020, respectively. Findings: Survival time for COVID-19 in-patients was six days (precision=252·84). The case mortality rate was 20·83% (95% confidence interval 20·67% to 20·99%). The correlation between reported and predicted COVID-19 deaths was near perfect (0·94, 95% confidence interval 0·91 to 0·97; p<0.0001). Joinpoint regression identified four joinpoints for predicted cumulative COVID-19 deaths: DPC, 6·29% (31 Jan to 2 Mar 2020), 27·08% (2 Mar to 25 Mar 2020), 20·02% (25 Mar to 3 Apr 2020), 14·33% (3 Apr to 10 Apr 2020), and 8·49% (10 Apr to 19 Apr 2020). COVID-19 deaths were predicted to rise to 45,236 by 30 Apr 2020. Interpretation: The mortality rate of COVID-19 in-patients is approximately one fifth, leading to 33,730 additional deaths by 30 Apr 2020. Future research is required to confirm these estimates in specific subgroups of COVID-19 patients. Funding Statement: No authors received funding to support this work. Declaration of Interests: No support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.