History of coronary heart disease increases the mortality rate of COVID-19 patients: a nested case-control study

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

Background: China has experienced an outbreak of a novel human coronavirus (SARS-CoV-2) since December 2019, which quickly became a worldwide pandemic in early 2020. There is limited evidence on the mortality risk effect of pre-existing comorbidities for coronavirus disease 2019 (COVID-19), which has important implications for early treatment. Objective: Evaluate the risk of pre-existing comorbidities on COVID-19 mortality, and provide clinical suggestions accordingly. Method: This study used a nested case-control design. A total of 94 publicly reported deaths in locations outside of Hubei Province, China, between December 18th, 2019 and March 8th, 2020 were included as cases. Each case was matched with up to three controls, based on gender and age (94 cases and 181 controls). The inverse-probability-weighted Cox proportional hazard model was performed. Results: History of comorbidities significantly increased the death risk of COVID-19: one additional pre-existing comorbidity led to an estimated 40% higher risk of death (p<0.001). The estimated mortality risk in patients with CHD was three times of those without CHD (p<0.001). The estimated 30-day survival probability for a profile patient with pre-existing CHD (65-year-old female with no other comorbidities) was 0.53 (95% CI [0.34-0.82]), while it was 0.85 (95% CI [0.79-0.91]) for those without CHD. Older age was also associated with increased death risk: every 5-year increase in age was associated with a 20% increased risk of mortality (p<0.001). Conclusion: Extra care and early medical intervention are needed for patients with pre-existing comorbidities, especially CHD.