| Patterns of SDU | (n = 82) |
| Types of psychoactive substance used during SDU in past year |
| Ketamine | 1.2 |
| Methamphetamine | 31.7 |
| Cocaine | 1.2 |
| Cannabis | 8.5 |
| Ecstasy | 3.7 |
| Dormicum / Halcion / Erimin 5 / Hypnotic drugs (non-prescription) | 0.0 |
| Heroin | 0.0 |
| Cough suppressant (not for curing cough) | 1.2 |
| Amyl nitrite | 80.5 |
| GHB/GBL | 31.7 |
| 5-methoxy-N, N-diisopropyltryptamine (Foxy) | 4.9 |
| Mephedrone | 0.0 |
| Poly-use of psychoactive substances in lifetime |
| No | 69.5 |
| Yes | 30.5 |
| Time since the first episode of SDU |
| < 1 year | 40.2 |
| 1–2 years | 15.9 |
| 3–5 years | 15.9 |
| > 5 years | 28.0 |
| Frequency of SDU in the past year |
| 1 episode/month | 37.8 |
| 1–2 episodes/month | 29.3 |
| ≥ 3 episodes/month | 32.9 |
| Condomless anal intercourse during SDU in the past year |
| No | 48.8 |
| Yes | 51.2 |
| Drug cessation/rehabilitation services provided by governmental organizations |
| No | 97.6 |
| Yes | 2.4 |
| Drug cessation/rehabilitation services provided by non-governmental organizations |
| No | 90.2 |
| Yes | 9.8 |
| Details of the most recent episode of SDU |
| Number of participants |
| 2 | 78.0 |
| ≥ 3 | 22.0 |
| Alcohol consumption |
| No | 85.4 |
| Yes | 14.6 |
| Use of erectile dysfunction drugs |
| No | 69.5 |
| Yes | 30.5 |
| Group sex |
| No | 80.5 |
| Yes | 19.5 |
| Condomless anal intercourse |
| No | 48.8 |
| Yes | 51.2 |
| Perceptions related to PrEP (among participants with experience of SDU in the past year who were not on PrEP) | (n = 70) |
| Willingness to take once-daily oral pill as PrEP in the next six months after being briefed some facts of PrEP |
| No (definitely not/probably not/neutral) | 32.9 |
| Yes (probably will/definitely will) | 67.1 |
| Willingness to pay (HK$ per month) for using once-daily oral pill as PrEP (among those with willingness to take PrEP in the next six months, n = 56) |
| ≤ 300 | 24.2 |
| 301–500 | 14.3 |
| 501–1000 | 18.6 |
| 1000–2000 | 21.4 |
| 2001–4000 | 17.1 |
| 4001–6000 | 2.9 |
| 6001–8000 | 1.4 |
| > 8000 | 0.0 |
| Perceptions related to PrEP based on the TPB |
| Positive attitudes toward PrEP (% agree) |
| PrEP can reduce your chance of HIV infection during SDU | 81.4 |
| PrEP would reduce your worry of HIV infection when having condomless sex during SDU | 64.3 |
| PrEP provides you more choice for HIV prevention | 84.3 |
| Positive Attitude Scalea | 8.1 (1.3) |
| Negative attitudes toward PrEP (% agree) |
| Psychoactive substances that are used during SDU would reduce the protective effect of PrEP | 17.1 |
| Psychoactive substances that are used during SDU would aggravate the side-effects of PrEP | 30.0 |
| Psychoactive substances that are used during SDU would make you forget to take PrEP | 28.6 |
| Daily use of PrEP would cause severe financial burden for you | 80.0 |
| You will be stigmatized by medical professionals when you are using PrEP-related services | 37.1 |
| Negative Attitude Scaleb | 10.2 (2.2) |
| Perceived subjective norm related to PrEP |
| People who are important to you will support you to use PrEP |
| Disagree/neutral | 32.9 |
| Agree | 67.1 |
| Perceived behavioral control to use PrEP |
| In general, you are confident in taking PrEP every day in the next six months |
| Strongly disagree/disagree/neutral | 35.7 |
| Agree/strongly agree | 64.3 |
