Effect of an express testing service for gay and bisexual men on HIV testing frequency in Sydney, Australia: a cohort study.

Background: HIV infection in gay and bisexually active men (GBM) is an international public health concern and increasing HIV testing frequency is an important prevention goal. In this study we assessed the effect of introducing the Xpress clinic on repeat HIV testing in high-risk GBM in Sydney, Australia. Methods: The study population consisted of higher-risk (>5 male partners in the preceding 3 months) HIV-negative GBM attending the Sydney Sexual Health Centre for HIV screening between 1 October 2009 and 31 December 2013 (12 months before Xpress was introduced and 3 years after). Poisson regression models were used to calculate the average annual trend of retesting within 6 months by quarter, and a retrospective cohort was constructed in which multivariate regression methods were used to assess the association between attendance at the Xpress clinic and repeat HIV testing in 6 months. Results: Among high-risk GBM, HIV retesting increased from 32% in Quarter 1 of 2011 to 48% in Quarter 4 of 2013 (Ptrend<0.001). There was no significant trend in the proportion of high-risk GBM retesting within 6 months by quarter in the period before Xpress (1 October 2009-30 September 2010; Ptrend=0.69), but there was a significant upward trend after Xpress implementation (1 January 2011-31 December 2013; Ptrend<0.001). The summary rate ratio in the before versus during Xpress period in all GBM was 1.27 (95% confidence interval (CI) 1.15-1.40; P<0.001). In the multivariate analysis, attending the Xpress clinic was independently associated with retesting within 6 months of an initial test (adjusted OR 2.78; 95% CI 2.12-3.66; P<0.001) after adjusting for other demographics and risk factors. Conclusions: This study consistently shows that optimising current services by introducing express clinics was able to increase HIV testing frequency in high-risk GBM and should be adopted more widely.