Characteristics for studies included in the systematic review and meta-analysis
| Author | Country | Sample size (n) | Study type | Study period | Age, year | Male (%) | Covariates adjusted for | QoE | Quality score |
| Zhang12 | China | 3430 | Cohort | 31 Dec 2019–20 Feb 2020 | Median: 64 (IQR: 55–68) | 53 | Age, sex, diabetes, coronary heart disease, cerebrovascular disease, and chronic renal disease, in-hospital medications (antiviral drug and lipid-lowering drug). | Moderate | 9 |
| Huang27 | China | 50 | Cohort | 7 Feb 2020–3 Mar 2020 | – | 54 | – | Low | 7 |
| Mancia28 | Italy | 37 031 | Case–control | 21 Feb 2020–11 Mar 2020 | Mean: 69 (SD: 13) | 63 | Age, sex, comorbidities and exposure to treatments. | Moderate | 8 |
| Li29 | China | 1178 | Cohort | 15 Jan 2020–15 Mar 2020 | Median: 56 (IQR: 38–67) | 46 | – | Medium | 8 |
| Mehta26 | United States | 18 472 | Cohort | 8 Mar 2020–12 Apr 2020 | Mean: 49 (SD: 21) | 40 | – | Moderate | 7 |
| Meng30 | China | 417 | Cohort | 11 Jan 2020–23 Feb 2020 | Median: 64.5 (IQR: 55.8–69.0) | 57 | – | Moderate | 8 |
| Zhang31 | China | 90 | Cohort | – | – | – | Age, sex, days from symptom onset to hospital admission, and exposure to treatments. | Low | 7 |
| Guo32 | China | 187 | Cohort | 23 Jan 2020–23 Feb 2020 | Mean: 59 (SD: 14.66) | 49 | – | Moderate | 7 |
| Bean33 | England | 1200 | Cohort | 1 Mar 2020–13 Apr 2020 | Mean: 68 (SD: 17) | 57 | Age, sex, hypertension, diabetes, chronic kidney disease, and ischaemic heart disease/heart failure. | Moderate | 9 |
| Zeng11 | China | 247 | Cohort | 5 Jan 2020–8 Mar 2020 | – | – | – | Moderate | 8 |
| Yang34 | China | 251 | Cohort | 5 Jan 2020–3 Mar 2020 | – | – | – | Moderate | 8 |
| Richardson35 | United States | 5700 | Case series | 1 Mar 2020–4 Apr 2020 | Median: 63 (IQR 52–75) | 60 | – | Moderate | 8 |
| Ip36 | United States | 3017 | Cohort | – | – | – | – | Moderate | 8 |
| Fosbøl37 | Denmark | 4480 | Cohort | 1 Feb 2020–4 May 2020 | Median: 54.7 (IQR 40.9–72.0) | 48 | Age, sex; education; income; history of myocardial infarction, heart failure, kidney disease, stroke, peripheral artery disease, atrial fibrillation, diabetes, COPD, and malignancy; and use other antihypertensive drugs, lipid-lowering drugs, anticoagulants, or nonsteroidal anti-inflammatory drugs. | Moderate | 9 |
COPD, chronic obstructive pulmonary disease; QoE, quality of evidence.