Zheng (2020)
Risk factors of critical & mortal COVID-19 cases: A systematic literature review and meta-analysis
Patient characteristics
Age (>65 years vs. <=65 years)
COVID-19 (severe/fatal)
Odds ratio: 6.010 (3.950-9.160) Univariate analysis





Thirteen studies were included in Meta-analysis, including a total number of 3027 patients with SARS-CoV-2 infection - relevant studies published between Jan 1, 2020 and Mar 20, 2020

The median ages ranged from 49 to 70.5 years old in the critical/mortal group across the enrolled studies. The median ages ranged from 37 to 62 years old in the non-critical group. The median ages were generally higher in critical/death group compared to the non-critical group. Furthermore, age over 65 years was analyzed as a subgroup by Guan and Tian (with a total amount of 1273 patients). Meta-analysis showed that the proportion of patients older than 65 years was higher in critical/death group compared to the non-critical group. There was no heterogeneity in the estimates of male, age over 65 years old and current smoking among the identified studies with I^2=0.


COVID-19 (severe/fatal)


(1) groups involving critical illness or death and non-critical illness (2) patients should be confirmed to have been infected by 2019 novel coronavirus (3) study designs included randomized controlled trials, nonrandomized controlled trials, case?control studies, cohort studies, cross?sectional studies, and also case reports (4) at least one outcome reported among demographical characteristics, comorbidities and clinical manifestations (5) study sample was larger than 20. We excluded duplicate reports, abstracts from conferences and commentary articles.

Patient characteristics


aged over 65 might face a greater risk of developing into the critical or mortal condition

<=65 years

>65 years

Odds ratio

6.010 (3.950-9.160)




age, male, current smoking, diabetes, cardiovascular disease, respiratory disease and malignancy, fever, headache, myalgia or arthralgia, cough, sputum production, fatigue, diarrhea, nausea or vomiting, Shortness of breath/Dyspnea, white blood cells, creatinine, aspartate transaminase, high-sensitivity cardiac troponin I (hs-cTnI), Procalcitonin, lactate dehydrogenase, D-dimer