The primary results of this study confirm that male clients in Yunnan, China are particularly vulnerable for HIV infection given their drug use behaviors and sexual relations with multiple types of sexual partners. The HIV positive rates of clients in this study are comparable to provincial averages described in provincial surveillance reports by the Yunnan Province Center for Disease Control (CDC), which averaged at 4% in 2005 (Yunnan CDC Comprehensive Report, 2005). Among the 315 male clients surveyed for this study, 60% were local residents and among the 59.7% with a regular sexual partner (wife or girlfriend), 62.8% reported a median of two additional casual sexual partners per month. Overall HIV prevalence was 6.0%; among drug using clients prevalence was 30.8%. 33.7% of respondents reported that they always use condoms in commercial sex and 63.5% that they used a condom in last commercial sexual episode. This study indicated drug use (AOR: 6.1; 95% CI: 1.7–21.4) and lack of a regular sexual partner (AOR: 6.3; 95% CI: 1.8–21.9) as primary risk factors significantly associated with HIV infection.
One possible explanation why clients without regular sexual partners may be at higher risk for HIV infection is that these clients are likely to visit FSWs more frequently or have higher rates of partner change, thus increasing their likelihood of having sex with an infected partner. To test this we compared frequency of commercial sex between clients with and without regular partners and found that 51.2% of clients without regular partners visited FSWs more than 4 times per month whereas only 30.9% (p<0.001) of clients with regular partners visited FSWs more than 4 times per month. Why this study did not find condom use rates to be associated with HIV serostatus may largely be due to a downward bias in self-reported condom use rates. Other studies have also found a weak association between self-reported condom use rates and HIV infection.[14
] Another possibility is that undetected drug using behaviors may be masking the actual risks associated with sexual transmission of HIV, discussed in further detail below.
The HIV risk associated with drug use is well documented and our study corroborates this with a 6.1 fold increased risk seen among clients identified to be drug users through self-report or positive urine drug tests. The HIV risk associated with drug use is thought to be primarily due to injecting drugs but our study did not find a difference in the proportion of HIV-infected drug users who self-identified as injectors as opposed to those who did not (42% vs.33%, P=0.52). This lack of statistical significance is likely due in part to the small numbers of self-reported injectors, as well as due to the misclassification of injectors who did not self-report.
This study faces several limitations. First is that the study sample may not be representative of the overall male client population in Kaiyuan. Due to study subject recruitment methods, this sample may over-represent clients who purchase sex at lower-risk venues such as karaoke halls where clients maintain longer term, personal relations with FSW, making these men more accessible via “FSW-client” referral methods. Clients who patronize FSW in lower-risk venues are also relatively easier for outreach workers to access because their commercial sexual activity is location specific, whereas clients who visit higher risk FSWs are more difficult to identify because sexual transactions are negotiated in non-fixed settings with sex often occurring in private residences.[15
] Past studies have shown that FSW at higher-risk venues are significantly more likely to be HSV-2 positive, suggesting that their clients may also at higher risk for sexually transmitted infections including HIV[14
]. These factors suggest a systematic bias in our study sample that may under-represent the behaviors of clients who visit higher-risk venues, resulting in an underestimation of the risk associated with the types of venues clients visit. Our sample also suffers from self-selection bias and self-reporting bias; however, we cannot determine the direction of these biases without better information about systematic differences between our sample and the larger client population in Kaiyuan. Lastly, because of the convenience sampling methods used and the other biases mentioned above, this sample may not be entirely representative of the larger client population of China.
In addition because urinalysis screening can only identify opiate use within the last four to five days, this study may underestimate the number of drug using clients. In fact, five of the subjects in this study who denied past illicit drug use were identified as drug users due to positive urinalysis results, confirming the underreporting and possibly underestimating the actual risk for HIV infection associated with drug use.
Further research on the sexual and other HIV related risk behaviors of male clients is important for several reasons. In China men often exercise greater decision-making power regarding condom use during sex, which has strong implications for client-side condom interventions. Past studies have also found that FSW in China are a highly mobile group which presents challenges to conducting interventions with this group,[3
] whereas this study found that clients tend to purchase sex locally (60% of clients were Kaiyuan residents vs. 28% among FSW who work in Kaiyuan [3
]), suggesting that clients are less mobile than FSW and thus more accessible for targeted intervention programs.
As a group at high risk of contracting HIV/STDs, male clients are thought to be both an important core transmitter group[17
] or so-called `bridge population,[18
] forming critical transmission networks between high-risk groups such as FSW and IDU to the general population. The key findings of our study, that a majority of clients were local, had multiple sexual partners, and that the major risk factors for HIV infection were drug use and not having a regular sexual partner (wife/girlfriend), point to the tremendous need for public health interventions among this group. Past studies have also found that FSW in China are a highly mobile group which presents challenges to conducting interventions with this group,[2
] whereas this study found that clients tend to purchase sex locally (60% of clients were Kaiyuan residents vs. 28% among FSW who work in Kaiyuan [2
]), suggesting that clients are less mobile than FSW and thus more accessible for targeted intervention programs. The high numbers of sexual partners, even among those with a wife or girlfriend, and low rates of self-reported condom use provide areas to focus prevention efforts. This study also shows that some male clients in China engage in injection drug use which, when coupled with multiple sexual partners and low condom use, has profound implications for the transmission of HIV to the general population.