AIDS | 2019
Diverging trends in incidence of HIV versus other sexually transmitted infections in HIV-negative men who have sex with men (MSM) in Amsterdam.
Abstract
OBJECTIVES\nWe investigated changes in incidence rates of HIV and sexually transmitted infections (STI) and trends in sexual behavior in MSM from 2009-2017.\n\n\nDESIGN\nOpen prospective cohort study.\n\n\nMETHODS\nHIV-negative MSM enrolled in the Amsterdam Cohort Studies were included. Participants semiannually completed a questionnaire on sexual behavior and were tested for HIV-1, syphilis, and urethral, anal and pharyngeal chlamydia and gonorrhea. Time trends in incidence rates were analyzed using exponential survival models.\n\n\nRESULTS\nDuring follow-up, 42 of 905 MSM acquired HIV. The HIV incidence rate was 1.9/100 person-years (PY) (95%-confidence interval (CI) 1.0-3.7) in 2009 and decreased to 0.5/100 PY (95%-CI 0.2-1.4) in 2017 (p\u200a=\u200a0.03). The largest decrease was observed in participants aged ≥35 years (p\u200a=\u200a0.005), while the trend remained stable in 18-34 year olds (p\u200a=\u200a0.4). The incidence rate for any bacterial STI was 16.8/100 PY (95%-CI 13.4-21.0) in 2010, and increased to 33.1/100 PY (95%-CI 29.0-37.9) in 2017 (p\u200a<\u200a0.001). Between 2009-2017, the percentage reporting condomless anal sex (CAS) with casual partners increased from 26.9% to 39.4% (p\u200a<\u200a0.001), and the mean number of casual partners from 8 (95%-CI 8-8) to 11 (95%-CI 10-11) (p\u200a=\u200a0.05). CAS with steady partner(s) remained stable over time (p\u200a=\u200a0.5).\n\n\nCONCLUSIONS\nAmong MSM in Amsterdam, incidence rates of HIV versus other STI show diverging trends. The increase in STI incidence coincides with a decrease in condom use with casual partners. The decrease in HIV incidence, despite increased sexual risk behavior, suggests that other HIV prevention methods have been successful in reducing HIV transmission among MSM.