Participants and procedure
A cross-sectional study was conducted among MSM persons who lived in Liuzhou, China from November 2017 to May 2019. Participants were recruited through a nonprobability sampling method and the main methods of recruitment included: (1) finding the “seed” subjects, through peer introduction and the “snowball” sampling method to find other research subjects; (2) via network platform (i.e., websites and social media applications); and (3) recruited by trained and experienced peer educators from spaces frequented by MSM, such as parks, bathhouses, and bars. The inclusion criteria were as follows: (1) aged 15 years or older; (2) born biologically male; (3) had anal and/or oral intercourse with at least one man in the last six months; (4) HIV-negative; and (5) residing in Liuzhou. HIV-positive persons were excluded and referred to the local Centers for Disease Control and Prevention (CDC). Eligible participants were briefed about the study’s purpose and informed consent was obtained from each subject prior to enrolling each into the study. Each participant completed a face-to-face interview questionnaire in a private room, which took approximately 20 minutes to complete. Respondents were compensated 50 RMB (about 7.5 US dollars) for their time spent on the survey. A total of 854 participants were contacted, of whom 829 were eligible and completed the survey. The study protocol was approved by the ethics committee of Anhui Medical University.
Three milliliters of blood samples was collected and transported to the laboratory of local CDC within 12 hours. Plasma specimens were screened for HIV antibodies by using enzyme-linked immunosorbent assay (ELISA; Beijing Modern Gaoda Biotechnology Co., Beijing, China), and positive tests were confirmed by a HIV-1/2 Western blot assay (HIV Blot 2.2 WBH; Genelabs Diagnostics, Singapore).
Demographic information collected include age, household registration, ethnicity, occupation, education level, marital status, personal monthly income, sexual orientation, history of sexually transmitted diseases (STDs) other than HIV, and recruitment source.
In all, HIV/AIDS knowledge was measured with six questions for which two questions were on mosquito bites and number of sex partners in HIV transmission, another two questions on condom use and lubricant use in HIV prevention, and one also on blood testing for HIV as well as one other question on HIV/AIDS treatment. There was one point assigned for a correct answer, 0 for a wrong answer or an answer of unknown or unsure. The total score for HIV literacy ranged from 0 to 6, and a score equal to or greater than 4 was classified as “high level of HIV/AIDS knowledge” and scores below 4 were classified as “low level of HIV/AIDS knowledge”.
Items for assessing sexual behaviors were made up of two scales (homosexual and heterosexual). The scale of homosexual behaviors was measured by the following questions: total number of male sexual partners, age at first anal sex with men, number of anal sex partners in the past month, condom use in anal sexual intercourse, oral sexual behavior with men, and commercial sex with men in the past six months. Heterosexual behaviors was evaluated by the following questions: total number of female sexual partners, age at first anal sex with women and heterosexual behavior in the past six months.
Participants were asked if they had ever taken any drugs (including ecstasy, heroin, marijuana, opium, crystal meth, methamphetamine, cocaine, sedatives or stimulants, etc.) and the frequency of taking the drugs in the past month. In addition, participants were also asked about their HIV testing history and whether they knew the test results.
To assess the willingness of PrEP, respondents were provided a brief description of PrEP (i.e., PrEP is a daily medication that people who do not have HIV take to prevent getting infected with HIV. PrEP is taken before someone is exposed to HIV.), and then asked them to select a response from a 5-point Likert scale (1 = definitely not, 2 = probably not, 3 = not sure, 4 = probably will, 5 = definitely will). Responses were then dichotomized. Choices 1, 2, and 3 were classified into the “unwilling to use PrEP” group and choices 4 and 5 were classified into the “willing to use PrEP” group.
All statistical analyses were performed using SPSS version 23.0 (SPSS Inc., Chicago, IL, USA). Descriptive statistics, including the frequency, percentage, mean and standard deviation (SD) were reported. Chi-square test and t-test were used to compare differences in demographic, HIV/AIDS knowledge, sexual behaviors, drug use and HIV testing history between MSM who were willing and those who unwilling to use PrEP. Variables with a p-value<0.05 in the univariate analysis were selected and further explored in a multivariable logistic regression model. Multivariate logistic regression analyses were performed to evaluate the factors associated with willingness to use PrEP. Odd ratios (ORs) and 95% confidence intervals (95% CI) were calculated. A two-tailed p < 0.05 was considered as statistically significant.