| Age (Mean, SD) | 38.1±6.5 | |
| IQR | 33.8 – 42.1 | |
| ≤29 | 38 | 7.3 |
| 30 – <40 | 304 | 58.4 |
| ≥40 | 179 | 34.3 |
| Education | | |
| Primary school and lower | 61 | 11.7 |
| Secondary school | 240 | 46.1 |
| High school or higher | 220 | 42.2 |
| Occupation status | | |
| Employed | 400 | 76.8 |
| Unemployment/students | 121 | 23.2 |
| Monthly income (mean, SD)a | 5.8±4.8 | |
| IQR | 3 – 7 | |
| Marital status | | |
| Married/cohabited with a partner | 193 | 37.0 |
| Single/separated/widow | 328 | 63.0 |
| HIV status | | |
| HIV-positive | 184 | 35.3 |
| HIV-negative | 337 | 64.7 |
| Total years of heroin use (mean, SD) | 9.1±5.0 | |
| IQR | 6 – 12 | |
| ≥ 10 years | 282 | 54.1 |
| < 10 year | 239 | 45.9 |
| Methadone treatment status | | |
| Current treatment (≥1 year) | 107 | 20.5 |
| Current treatment (<1 year) | 109 | 20.9 |
| Not current treatment | 305 | 58.6 |
| Frequency of using condom when had sex during 3 months before survey | | |
| Did not have sex or using condom all of the time when had sex | 369 | 70.8 |
| Most of the time | 21 | 4.1 |
| Some of the time | 20 | 3.8 |
| None of the time | 111 | 21.3 |
| Depression | | |
| Normal/mild | 309 | 59.3 |
| Moderate/severe/extremely severe | 212 | 40.7 |
| Anxiety | | |
| Normal/mild | 298 | 57.2 |
| Moderate/severe/extremely severe | 223 | 42.8 |
| Stress | | |
| Normal/mild | 385 | 73.9 |
| Moderate/severe/extremely severe | 136 | 26.1 |