| Subgroups | Prevalence % (95% CI) | No of studies | Heterogeneity | |
| I2 (%) | p Value | |||
| Sampling method | ||||
| Voluntary confidential testing and network | 3.8 (2.5 to 5.6) | 6 | 55.46 | 0.05 |
| MSM venues | 2.8 (1.6 to 4.9) | 12 | 78.01 | <0.01 |
| Respondent-driven sampling and snowballing | 2.1 (1.4 to 2.9) | 9 | 48.63 | 0.05 |
| Sample size | ||||
| ⩽200 | 3.8 (2.3 to 6.5) | 13 | 64.07 | <0.01 |
| >200 | 2.1 (1.7 to 2.7) | 13 | 54.96 | 0.01 |
| Study location | ||||
| Beijing | 2.6 (1.7 to 3.9) | 5 | 68.52 | <0.01 |
| Guangdong | 2.3 (1.4 to 3.9) | 6 | 43.36 | 0.12 |