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Objectives: HIV diagnoses among men who have sex with men (MSM) in several high-income countries, including Australia, have increased substantially over recent years. Australia, in line with global prevention strategies, has emphasised a 'test and treat' HIV prevention strategy which relies on timely detection of HIV through frequent testing by those at risk. We examined trends in repeat testing among MSM defined as 'high-risk' according to Australian testing guidelines., Methods: HIV test records from MSM attending high caseload clinics in Melbourne 2007-2013 and classified as high-risk were analysed. Binary outcomes of 'test within 3 months' and 'test within 6 months' were assigned to tests within individuals' panel of records. Negative binomial regressions assessed trends in overall HIV testing and returning within 3 and 6 months. Annualised proportions of return tests (2007-2012) were compared using two-sample z tests., Results: Across 18 538 tests among 7117 high-risk MSM attending primary care clinics in Melbourne (2007-2013), the number of annual HIV tests increased (p<0.01). Between 2007 and 2012 annualised proportions of tests with a subsequent test within 3 and 6 months also increased (p<0.01); however, by 2012 only 36.4% and 15.1% of tests were followed by another test inside 6 and 3 months, respectively., Conclusions: Repeat testing among high-risk MSM in Australia remains unacceptably low, with recent modest increases in testing unlikely to deliver meaningful prevention impact. Removing known barriers to HIV testing is needed to maximise the potential benefit of test and treat-based HIV prevention., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Objectives: Directly measuring disease incidence in a population is difficult and not feasible to do routinely. We describe the development and application of a new method for estimating at a population level the number of incident genital chlamydia infections, and the corresponding incidence rates, by age and sex using routine surveillance data., Methods: A Bayesian statistical approach was developed to calibrate the parameters of a decision-pathway tree against national data on numbers of notifications and tests conducted (2001-2013). Independent beta probability density functions were adopted for priors on the time-independent parameters; the shapes of these beta parameters were chosen to match prior estimates sourced from peer-reviewed literature or expert opinion. To best facilitate the calibration, multivariate Gaussian priors on (the logistic transforms of) the time-dependent parameters were adopted, using the Matérn covariance function to favour small changes over consecutive years and across adjacent age cohorts. The model outcomes were validated by comparing them with other independent empirical epidemiological measures, that is, prevalence and incidence as reported by other studies., Results: Model-based estimates suggest that the total number of people acquiring chlamydia per year in Australia has increased by ∼120% over 12 years. Nationally, an estimated 356 000 people acquired chlamydia in 2013, which is 4.3 times the number of reported diagnoses. This corresponded to a chlamydia annual incidence estimate of 1.54% in 2013, increased from 0.81% in 2001 (∼90% increase)., Conclusions: We developed a statistical method which uses routine surveillance (notifications and testing) data to produce estimates of the extent and trends in chlamydia incidence., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Background: Chlamydia is the most commonly notified sexually transmitted infection (STI) in Australia. Incidence studies of chlamydia in men who have sex with men (MSM) are rare and offer important public health information., Objective: To determine chlamydia incidence in MSM presenting at high caseload clinics and describe predictors of infection., Methods: The Victorian Primary Care Network for Sentinel Surveillance of bloodborne viruses and STIs (VPCNSS) links testing, demographic and behavioural data from individual testers at participating clinics. Data from MSM with more than one chlamydia test at the VPCNSS site between April 2006 and June 2010 were included. Chlamydia incidence per 100 person-years (PY) was calculated and Cox regression used to examine predictors of incidence., Results: 1206 positive tests for chlamydia were detected among 6333 MSM across 11,409 PY of follow-up. Overall chlamydia incidence was 10.6/100 PY (95% CI 10.0 to 11.2) and was highest among MSM aged 16-29 years (12.9/100 PY, 95% CI 11.7 to 14.1), presenting with STI symptoms (16.0/100 PY, 95% CI 14.2 to 18.0), HIV positive (18.5/100 PY, 95% CI 16.6 to 20.6) and self-identified sex workers (14.3/100 PY, 95% CI 10.0 to 20.6). Significant predictors of chlamydia infection among MSM were younger age (adjusted hazard ratio (aHR)=1.9, 95% CI 1.5 to 2.3), self-identifying as a sex worker (aHR=1.6, 95% CI 1.0 to 2.6), being HIV positive (aHR=2.6, 95% CI 1.8 to 3.8), presenting with STI symptoms (aHR=1.7, 95% CI 1.4 to 2.1) and reporting >10 sex partners in the past 6 months (aHR=2.5 95% CI 1.4 to 4.6)., Conclusion: These results show that MSM represent a key risk population for chlamydia in Australia and identify a number of high-risk MSM subpopulations for whom clinical and public health interventions are warranted.

Objectives: Australian guidelines recommend annual testing for HIV and sexually transmitted infections (STIs) for all men who have sex with men (MSM) and 3-6 monthly testing for those at higher risk as defined by behavioural criteria. We assessed HIV/STI re-testing rates among MSM attending primary care clinics., Methods: We conducted a retrospective follow-up of HIV negative MSM tested for HIV or STIs (chlamydia or syphilis) at four primary care clinics in the 9-month period: April to December 2006. Re-testing rates for these infections were calculated over 18 months. Logistic regression was undertaken to identify predictors of guideline adherence., Results: Of the MSM requiring annual HIV testing according to the guidelines, the re-testing rates at 1 y were 35% (762/2163). Among the higher risk MSM, 6-monthly HIV re-testing rates were 15% (283/1862). Within the subgroup who reported 11 or more male sexual partners within the past 6 months, HIV re-testing rates within 6 months were 19%. Independent predictors of HIV re-testing within 6 months in higher-risk MSM were reporting 11 or more male sexual partners in the last 6 months (AOR 3.1, 95% CI 1.8 to 4.8); being born overseas (AOR 2.0, 95% CI 1.2 to 3.4); and previous HIV testing more than 12 months earlier (AOR 3.3, 95% CI 1.9 to 5.5)., Conclusion: There is poor adherence to national guidelines that recommend regular re-testing of MSM for STIs, particularly among those at higher risk who require more frequent testing. Clinical strategies are urgently needed to encourage more frequent HIV/STI testing among MSM, especially in the higher risk subgroup.