History of Coronary Heart Disease Increases the Mortality Rate of Coronavirus Disease 2019 (COVID-19) Patients: A Nested Case-Control Study Based on Publicly Reported Confirmed Cases in Mainland China

Tian Gu; Qiao Chu; Zhangsheng Yu; Botao Fa; Anqi Li; Lei Xu; Ruijun Wu; Yaping He

However, several gaps remain in the understanding of risk factors for mortality of COVID-19. First, most current research on pre-existing comorbidities of COVID-19 was based on univariate comparison, which did not account for important confounders such as age and gender [17] [18] [19] [20] . Second, no studies have investigated the hazard of the identified risk factors over time, or the probability of survival at a given time. Under the rapidly changing pandemic situation, it is crucial to provide timely survival-time guidance for implementing the targeted treatment to the high-risk patients in clinical practice. Third, most existing studies on mortality risk factors were focused on patients diagnosed in Wuhan, Hubei Province, with little understanding about the mortality risk factors outside of Hubei Province. The risk factors are likely different inside and outside of Hubei Province, since current research has found that the clinical symptom severity [5] and the fatality-case rate [9, 21] to be higher in Hubei Province (the center of outbreak) than cities outside of Hubei Province in China. Fourth, no studies thus far have taken into account the pandemic stage when evaluating mortality risk factors. It has been found that average daily attack rate in China was different before and after January 11 th 2020, since non-pharmaceutical interventions were taken by the government before this date [22] . The change of pandemic stage may also influence the risk factors for fatality associated with COVID-19.