Guan (2020)
Comorbidity and its impact on 1,590 patients with COVID-19 in China: A Nationwide Analysis
No. of comorbidities (With one comorbidity vs. Not present)
COVID-19 (severe/critical)
Hazard ratio: 1.790 (1.160-2.770) Adjusted model


Retrospective case study

Medical records


1590 cases from 575 hospitals in 31 province/autonomous regions/provincial municipalities

Of these 1590 cases, the mean age was 48.9 years. 686 patients (42.7%) were females. 647 (40.7%) patients were managed inside Hubei province, and 1334 (83.9%) patients had a contact history of Wuhan city. The most common symptom was fever on or after hospitalisation (88.0%), followed by dry cough (70.2%). Fatigue (42.8%) and productive cough (36.0%) were less common. At least one abnormal chest CT manifestation (including ground-glass opacities, pulmonary infiltrates and interstitial disorders) was identified in more than 70% of patients. Severe cases accounted for 16.0% of the study population. 131 (8.2%) patients reached to the composite endpoints during the study.


10 Day

COVID-19 (severe/critical)


Patients who reached composite endpoints, which consisted of admission to intensive care unit, or invasive ventilation or death.


No. of comorbidities

With one comorbidity, e.g. diabetes, hypertension and other cardiovascular and cerebrovascular diseases

Not present

With one comorbidity


Hazard ratio

1.790 (1.160-2.770)




The age and smoking status were adjusted for in the proportional hazards regression model because they have been recognised as the risk factors of comorbidities even in the general population.

The HR was 1.79 (95%CI 1.16??2.77) among patients with at least one comorbidity and 2.59 (95%CI 1.61??4.17) among patients with two or more comorbidities.