title: Sexual risk behavior among HIV-uninfected men who have sex with men participating in a tenofovir preexposure prophylaxis randomized trial in the United States.
abstract: OBJECTIVE
  To evaluate for changes in sexual behaviors associated with daily pill use among men who have sex with men (MSM) participating in a preexposure prophylaxis trial.
  
  
  METHODS
  Randomized, double-blind, placebo-controlled trial. Participants were randomized 1:1:1:1 to receive tenofovir disoproxil fumarate or placebo at enrollment or after a 9-month delay and followed for 24 months.
  
  
  METHODS
  Four hundred HIV-negative MSM reporting anal sex with a man in the past 12 months and meeting other eligibility criteria enrolled in San Francisco, Atlanta, and Boston. Sexual risk was assessed at baseline and quarterly visits using Audio Computer-Assisted Self-Interview. The association of pill taking with sexual behavior was evaluated using logistic and negative-binomial regressions for repeated measures.
  
  
  RESULTS
  Overall indices of behavioral risk declined or remained stable during follow-up. Mean number of partners and proportion reporting unprotected anal sex declined during follow-up (P < 0.05), and mean unprotected anal sex episodes remained stable. During the initial 9 months, changes in risk practices were similar in the group that began pills immediately vs. those in the delayed arm. These indices of risk did not differ significantly after initiation of pill use in the delayed arm or continuation of study medication in the immediate arm. Use of poppers, amphetamines, and sexual performance-enhancing drugs were independently associated with one or more indices of sexual risk.
  
  
  CONCLUSIONS
  There was no evidence of risk compensation among HIV-uninfected MSM in this clinical trial. Monitoring for risk compensation should continue now that preexposure prophylaxis has been shown to be efficacious in MSM and other populations and will be provided in open-label trials and other contexts.
authors.affiliation: Bridge HIV, San Francisco Department of Public Health, San Francisco, CA, USA. albert.liu@sfdph.org
authors.forename: Albert Y
authors.initials: AY
authors.lastname: Liu
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.forename: Kata
authors.initials: K
authors.lastname: Chillag
authors.forename: Kenneth
authors.initials: K
authors.lastname: Mayer
authors.forename: Melanie
authors.initials: M
authors.lastname: Thompson
authors.forename: Lisa
authors.initials: L
authors.lastname: Grohskopf
authors.forename: Grant
authors.initials: G
authors.lastname: Colfax
authors.forename: Sonal
authors.initials: S
authors.lastname: Pathak
authors.forename: Roman
authors.initials: R
authors.lastname: Gvetadze
authors.forename: Brandon
authors.initials: B
authors.lastname: Oʼhara
authors.forename: Brandi
authors.initials: B
authors.lastname: Collins
authors.forename: Marta
authors.initials: M
authors.lastname: Ackers
authors.forename: Lynn
authors.initials: L
authors.lastname: Paxton
authors.forename: Susan P
authors.initials: SP
authors.lastname: Buchbinder
mesh_terms: D000225:Adenine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D000293:Adolescent; D000328:Adult; D019969:Amphetamine-Related Disorders; D019380:Anti-HIV Agents / Q000008:administration & dosage*; D001900:Boston / Q000453:epidemiology; D004311:Double-Blind Method; D005500:Follow-Up Studies; D005845:Georgia / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology / Q000517:prevention & control*; D018023:HIV Seronegativity; D007722:Health Knowledge, Attitudes, Practice; D018451:Homosexuality, Male / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D063065:Organophosphonates / Q000008:administration & dosage*; D018570:Risk Assessment; D012309:Risk-Taking; D012495:San Francisco / Q000453:epidemiology; D012747:Sexual Partners; D000068698:Tenofovir; D016896:Treatment Outcome; D047568:Unsafe Sex
chemical_list: D019380:Anti-HIV Agents; D063065:Organophosphonates; D000068698:Tenofovir; D000225:Adenine