Chlamydia trends in men who have sex with men attending sexual health services in Australia, 2004-2008.

Background: In most Australian settings, chlamydia notifications do not contain information on the gender of sexual partners. We assessed trends and predictors of chlamydia testing and positivity among men who have sex with men (MSM), attending sexual health services in Australia.
Methods: The Australian Collaboration for Chlamydia Enhanced Sentinel Surveillance (ACCESS) program was established in 2008 to collate demographic and chlamydia testing information from 25 sexual health services. We calculated the proportion tested and chlamydia positivity among MSM and assessed trends from 2004 to 2008 using a χ2 test and predictors using logistic regression.
Results: In the 5-year period, 11,777 MSM attended as new patients (first visit ever to the service) and the proportion tested for chlamydia increased significantly from 71% in 2004 to 79% in 2008 (P < 0.01). Independent predictors of chlamydia testing were younger age, residing in a metropolitan area (adjusted prevalence ratio [APR] = 1.23; 95% confidence interval [CI]: 1.19, 1.27), being Australian-born (APR = 1.03; 95% CI: 1.01, 1.06), being a traveler or migrant (APR = 1.09; 95% CI: 1.06, 1.12), and sex overseas in the past year (APR = 1.05; 95% CI: 1.03, 1.07). Overall chlamydia positivity was 8.6% (95% CI: 8.0%-9.2%). There was no significant trend in chlamydia positivity between 2004 and 2008. Independent predictors of chlamydia positivity were younger age, being a traveler or migrant (APR = 1.52; 95% CI: 1.26-1.84), and exclusive same-sex contact (APR = 1.28; 95% CI: 1.05-1.55).
Conclusions: This new national surveillance program demonstrates that the majority of MSM attending sexual health services was offered chlamydia testing and testing has increased over time. The MSM at highest risk of chlamydia were more likely to be tested. Chlamydia transmission was frequent but stable among MSM accessing clinical services.