Exclusion of possible overlaps
| Exposure | Outcome | All studies | Excluding possible overlap | ||
| Studies (n) | Pooled estimate (RR) | Studies (n) | Pooled estimate (RR) | ||
| Sex (male vs female) | Infection | 8 | 1.08 | 6 | 1.09 |
| Severe disease | 35 | 1.18 | 28 | 1.20 | |
| ICU | 11 | 1.38 | 11 | 1.38 | |
| Death | 14 | 1.50 | 11 | 1.34 | |
| Age (70+ vs 70−) | Infection | 4 | 1.65 | 4 | 1.65 |
| Severe disease | 7 | 2.05 | 7 | 2.05 | |
| ICU | 5 | 2.70 | 5 | 2.70 | |
| Death | 5 | 3.61 | 4 | 3.62 | |
Studies with possible overlap of patients were excluded from the analysis, results presented in bold. Possible overlap was assumed when studies were from the same region, recruitment period and hospital. In a group of studies with possible overlap only the largest study was included in the analysis. The results remained almost identical.
ICU, intensive care unit; RR, risk ratio.