Increase in Sexually Transmitted Infections Among Homosexual Men in Amsterdam in Relation to HAART

Objectives: We investigated if a rise in rectal gonorrhoea and early syphilis among men who have sex with men (MSM) in Amsterdam coincided with the introduction of highly active antiretroviral therapies (HAART) in July 1996 and determined risk factors for these sexually transmitted infections (STI).

Methods: Subjects were patients of the STI clinic of the municipal health service in Amsterdam. Surveillance data (1994-9) represented consultations (n=11 240) of MSM (n=6103). For analyses we used logistic regression.

Results: Comparing the periods before and after the introduction of HAART, the infection rate for rectal gonorrhoea increased from 4% to 5.4% (p=.001) and for syphilis, from 0.5% to 0.8% (p = 0.050). Independent risk factors for rectal gonorrhoea (younger age, western nationality, and concurrent infection with another STI) and for early syphilis (non-western nationality and concurrent infection with rectal gonorrhoea) did not change after HAART became available. For rectal gonorrhoea, however, the infection rate increased only among men who had exclusively homosexual contacts (OR 1.38, p<0.01), compared with bisexual men. For early syphilis, the infection rate increased only among men of western nationality (OR 3.38, p<0.01) compared to men of non-western nationality.

Conclusions: Infection rates of rectal gonorrhoea and early syphilis increased, indicating a change in sexual behaviour, possibly as a result of the introduction of HAART. For now, it is important to find out how sexual behaviour is changing and to keep monitoring trends in STIs (including HIV) among MSM in Amsterdam.