Study title
Influence of self-reported drug use and alcohol consumption on sexual risk behaviour among HIV infected persons in the Swiss HIV Cohort Study
Ref study 11033
Study language English
Contributing institutions
  • Sexual behaviour
  • Alcohol and drug use
  • Sexual orientation
Geographical space
The percentage of people with HIV infection is unfortunately rising despite prevention strategies. Our experience is that many patients experiencing HIV primary infection report use of illicit drugs or alcohol and consecutively unprotected sex. Recent studies have found that the use of specific party drugs such as methamphetamine, poppers, ecstasy and cocaine are associated with sexual risk. The potential link between substance use and risky sexual behaviour among HIV positive people is important to understand, so that interventions can be developed to minimize harms to both the infected individual and his partners.

Study Aims
To explore the completeness and consistency of the new questions related to sexual history. To evaluate the impact of different modes or recreational drug use and alcohol on sexual risk behaviour in HIV-positive people. To check associations between other socioeconomic factors and the impact of being on ART on sexual risk behaviour.

Study Design
Cross-sectional analysis of available cohort data from all patients with a regular follow up visit since 4/2007 (introduction of detailed questions on illicit drug use).
Access to antiretroviral therapy may have changed condom use behavior. In January 2008, recommendations on condom use for human immunodeficiency virus (HIV)-positive persons were published in Switzerland, which allowed for unprotected sex under well-defined circumstances ("Swiss statement"). We studied the frequency, changes over time, and determinants of unprotected sex among HIV-positive persons.

Self-reported information on sexual preference, sexual partners, and condom use was collected at semi-annual visits in all participants of the prospective Swiss HIV Cohort Study from April 2007 through March 2009. Multivariable logistic regression models were fit using generalized estimating equations to investigate associations between characteristics of cohort participants and condom use.

A total of 7309 participants contributed to 21,978 visits. A total of 4291 persons (80%) reported sexual contacts with stable partners, 1646 (30%) with occasional partners, and 557 (10%) with stable and occasional partners. Of the study participants, 5838 (79.9%) of 7309 were receiving antiretroviral therapy, and of these, 4816 patients (82%) had a suppressed viral load. Condom use varied widely and differed by type of partner (visits with stable partners, 10,368 (80%) of 12,983; visits with occasional partners, 4300 (88%) of 4880) and by serostatus of stable partner (visits with HIV-negative partners, 7105 (89%) of 8174; visits with HIV-positive partners, 1453 (48%) of 2999). Participants were more likely to report unprotected sex with stable partners if they were receiving antiretroviral therapy, if HIV replication was suppressed, and after the publication of the "Swiss statement." Noninjection drug use and moderate or severe alcohol use were associated with unprotected sex.

Antiretroviral treatment and plasma HIV RNA titers influence sexual behavior of HIV-positive persons. Noninjection illicit drug and alcohol use are important risk factors for unprotected sexual contacts.
Methods (description)
Analysis of data captured within the framework of the Swiss HIV Cohort Study (see Based upon prospectively collected clinical information and interviewer administered questionnaires on sexual behaviour.

Method: Standardised analysis of content, Participant observation, Standardised interviews face-to-face, Secondary analysis of individual data
Cohort profile: the Swiss HIV Cohort study.
Swiss HIV Cohort Study, Schoeni-Affolter F, Ledergerber B, Rickenbach M, Rudin C, Günthard HF, Telenti A, Furrer H, Yerly S, Francioli P. Int J Epidemiol. 2010 Oct;39(5):1179-89. PMID:19948780
The Swiss HIV Cohort Study: rationale, organization and selected baseline characteristics. Ledergerber B, von Overbeck J, Egger M, Lüthy R. Soz Praventivmed. 1994;39(6):387-94. PMID:7817627
Methods (instruments)
Replicated study No
  • Hasse, Barbara; Ledergerber, Bruno; Hirschel, Bernard; Vernazza, Pietro; Glass, Tracy R.; Jeannin, André; Evison, John-Marc; Elzi, Luigia; Cavassini, Matthias; Bernasconi, Enos; Nicca, Dunja; Weber, Rainer. 2010. Frequency and determinants of unprotected sex among HIV-infected persons: the Swiss HIV cohort study. Clinical Infectious Diseases, 51(11), 1314–1322. Online: 10.1086/656809
Financed by
Ethical approval No
Study type
Data availability
Source (Updates) Web
Date created 25.11.2012
Date modified 25.11.2012
Start - End date 01.12.2008 - 28.10.2010