High rates of sexually transmissible infections in HIV-positive patients in the Australian HIV Observational Database: a prospective cohort study

Brian P. Mulhall, Stephen Wright, Debbie Allen, Katherine Brown, Bridget Dickson, Miriam Grotowski, Eva Jackson, Kathy Petoumenos, Phillip Read, Timothy Read, Darren Russell, David J. Smith, David J. Templeton, Christopher K. Fairley, Matthew G. Law

Background In HIV-positive people, sexually transmissible infections (STIs) probably increase the infectiousness of HIV. Methods: In 2010, we established a cohort of individuals (n=554) from clinics in the Australian HIV Observational Database (AHOD). We calculated retrospective rates for four STIs for 2005-10 and prospective incidence rates for 2010-11. Results: At baseline (2010), patient characteristics were similar to the rest of AHOD. Overall incidence was 12.5 per 100 person-years. Chlamydial infections increased from 3.4 per 100 person-years (95% confidence interval (CI): 1.9-5.7) in 2005 to 6.7 per 100 person-years (95% CI: 4.5-9.5) in 2011, peaking in 2010 (8.1 per 100 person-years; 95% CI: 5.6-11.2). Cases were distributed among rectal (61.9%), urethral (34%) and pharyngeal (6.3%) sites. Gonococcal infections increased, peaking in 2010 (4.7 per 100 person-years; 95% CI: 5.6-11.2; Ptrend=0.0099), distributed among rectal (63.9%), urethral (27.9%) and pharyngeal (14.8%) sites. Syphilis showed several peaks, the largest in 2008 (5.3 per 100 person-years; 95% CI: 3.3-8.0); the overall trend was not significant (P=0.113). Genital warts declined from 7.5 per 100 person-years (95% CI: 4.8-11.3) in 2005 to 2.4 per 100 person-years (95% CI: 1.1-4.5) in 2011 (Ptrend=0.0016). Conclusions: For chlamydial and gonococcal infections, incidence was higher than previous Australian estimates among HIV-infected men who have sex with men, increasing during 2005-2011. Rectal infections outnumbered infections at other sites. Syphilis incidence remained high but did not increase; that of genital warts was lower and decreased.