BMC Public Health 2008, 8:180 http://www.biomedcentral.com/1471-2458/8/180 Table 4: Differences between prior and non-prior testors Variable n (%) responders Testors* (n = 276) Non-testors (n = 65) Mean age, years Sexual orientation: Self-defined as 'gay' Living in a stable relationship Swiss nationality Having had more than 10 sexual partners in the preceding 12 months Prior risk situation as motivation to seek testing New relationship as motivation to seek testing Routine check-up as motivation to seek testing Risk situation with anonymous partner Use of drugs in conjunction with sexual activity Risk situation longer than 3 months ago Estimated risk for HIV or STI infection (10-point Likert scale (0 = Very low; 10 = Very high)) 34 68% 30% 79% 27% 45% 29% 26% 42% 54% 45% 3.1 * Testors were defined as men with a history of HIV and any other STI. Non-testors had no history of either test. 28 35% 46% 77% 19% 49% 40% 17% 48% 48% 48% 2.5 p <0.001 <0.001 0.021 0.729 0.239 0.566 0.084 0.121 0.687 0.448 0.688 0.043 offered by other providers, irrespective of programme content and characteristics of fellow participants [26,27]. While demand was generally high in 2006, only few HIV- positive men requested care at the new service, mainly for STI testing. This is not surprising since HIV-positive men were not actively targeted in 2006 due to limited opening hours. However, this situation has changed since 2007 as with expanded opening hours Checkpoint is now also capable to offer long term HIV follow up, monitoring and treatment. Around 3.4% of HIV tests were positive, a relatively high number in comparison with testing centres at the univer- sity hospitals. In 2006, 4012 anonymous tests for HIV were conducted at the University hospital Zurich with 15 positive results (0.4%, personal communication). How- ever, with respect to the estimated HIV prevalence of 15% in the MSM population with sexual activity with anony- mous partners the number of positive tests in the first half-year period of Checkpoint seems still quite low. In an on-site cross-sectional study among gay/bisexual men conducted at 24 venues in Zurich in 1998, self-reported HIV status was recorded and compared to the results of HIV tests in saliva. 11.6% of participants were tested HIV- positive [5]. However, amongst men with a positive test result the majority were aware of their positive HIV serostatus (69% of those with a positive test, 8% of all par- ticipants). 3.6% of men that were tested positive were unaware of their HIV status. This figure is very close to the prevalence among men seeking testing reported in our study but the prevalence among subgroups of men may be much higher. For example, only few men in our sample reported "private parties" as site of the risk situation that motivated them to seek testing. In contrast, counsellors and outreach workers observe that "barebacking parties" with and without serosorting rules are becoming increas- ingly popular among gay men in Zurich. It seems that men engaging in this highly risky behaviour were not yet fully reached by the new service in 2006. New outreach strategies with on-site testing at sex parties, in dark rooms, saunas and cruising areas like motorway rest stops were started in 2007 under the name of Checkpoint mobile. Pre- liminary results indicate that the number of HIV tests per- formed increased by 50% with mobile testing while the prevalence of positive results nearly doubled. In the sam- ple of 2006, many men had a history of at least one STI test in the past and one third had suffered any STI previ- ously. This underlines the considerable burden that STI other than HIV pose to the health of MSM. In the percep- tion of counsellors there is also increasing awareness towards STI and the fraction of subjects who seek testing and treatment explicitly due to concerns over STI other than HIV is steadily rising. This study also has a number of limitations and results should therefore interpreted with care: The most impor- tant limitation is that the study is purely descriptive and we cannot present data on a control group, e.g., MSM that demand care elsewhere in Zurich. As the survey was mainly used for counselling purposes and was therefore administered prior to consultations and treatments, it was not possible to include questions relating to patients' eval- uation of the care they received, e.g., in terms of satisfac- tion with the new service. We therefore needed to rely on demand as a marker of acceptance within the MSM com- munity. Another limitation relates to the response rate. Since we lack data of non-responders, we cannot draw conclusions regarding potential differences between responders and non-responders. However, it is worth not- ing that the response rate of 64% relates to responses/con- sultations and thus underestimates the true response rate Page 7 of 9 (page number not for citation purposes)