People living with HIV/AIDS (PLWHA) (methods)
Monitoring behaviour among PLWHA is a sensitive issue because of the risks of stigmatisation, criminalisation or existing legal conditions regarding transmission of HIV or other STI. Any behavioural surveillance should be discussed with PLWHA organisations. The populations to be considered are people diagnosed with HIV and treated in specialised settings for their HIV infection as well as subpopulations: women, men self identified as heterosexuals or refusing self identification, men self identified as homosexuals or bisexuals. There is no referenced sampling method to monitor trends in the population of people living with HIV. In most countries, HIV declaration is anonymous, and hence there is no registry to serve as a reference population for sampling in medical settings.
In Europe, behavioural surveillance has been conducted mainly using service-based sampling.
To date, data have been collected in one-day studies, in cohorts and in cross-sectional studies. These methods are detailed below:
- One-day prevalence survey
- Cohort studies
- Cross-sectional repeated surveys
- Advantages and disadvantages of these methods are presented in a table
1. One-day prevalence survey
This type of survey aims at recruiting an exhaustive sample of subjects attending outpatient clinics or hospitalised on one fixed day, using a short questionnaire administered by the physician or the nurse in charge of treatment and medical care. Behavioural information is part of a questionnaire also covering medical information and the social situation. The questionnaire is completed during the visit. Data collection is initiated and organised by health state agencies. Such a survey can be performed annually. Feasibility depends on the organisation of HIV care in the country, the organisation of health administration to implement the study in all, or at least in large samples of, specialised settings. As data are collected by nurses and physicians, little infrastructure is needed. Participation of hospitals may vary across regions and years, however patient response rates are high. One-day studies will underrepresent both those patients who attend medical settings infrequently because they are in good health and have no need for treatment and those who have interrupted their treatment or do not comply to regular visits. Desirability bias in answering questions about behaviour, especially if questionnaires are more detailed than usual, might occur. This type of data collection allows only for short questionnaires, but the method is feasible and sustainable due to the limited resources needed.
2. Cohort studies
Cohort studies are mainly research tools focusing on clinical, physiopathological and therapeutic issues. To date, little interest has been given to behavioural issues. Only few cohorts collect behavioural data (e.g. the Swiss HIV Cohort Study, the French PRIMO cohort) or provide analysis of such data. This situation may change, as there is increasing interest in the link between treatment and prevention. Data collection within cohorts is facilitated by the availability of an existing research infrastructure, funding and technical assistance. However, existing cohorts are heterogeneous: some national cohorts are essentially longitudinal medical and biological databases (Swiss Cohort), others recruit a specific segment of subjects, such as individuals recently diagnosed (COPANA, France), seroconverters (CASCADE, France), patients co-infected (HEPAVIH, France); others have a local or regional basis. Cohort studies are not representative of the national population living with HIV, although some cover a large proportion of the target population or aim at exhaustivity. However, the key issue regarding use of the cohort as a surveillance tool is whether the cohort has ceased to include new cases or is continuing recruitement. Populations followed in the cohorts are selected both at inclusion and by attrition. Methods in use are either self-administered questionnaires or questions asked by the physician or nurse. The interest in second generation surveillance is the emerging with detailed medical and biological markers. Countries setting up new cohorts should be invited to include behavioural data. Validity is determined by the scope of the cohort, and comparability between countries is limited by the characteristics of patients recruited in the cohorts. Feasibility as a behavioural surveillance tool is facilitated by the fact that use is made of existing infrastructure at limited additional costs. Cohorts are long-term studies, and this also ensures sustainability.
3. Repeated cross-sectional surveys
Repeated cross-sectional surveys using either self administered questionnaires, face to face or computer-assisted confidential questionnaires can recruit large samples and collect detailed data to document indicators. Information from HIV notifications and medical setting case-loads can provide information allowing for the definition of random samples within services, allowing for a random selection of patients within the clinics. Such studies require considerable specific resources and are less likely to be sustainable. In the current situation, a brief questionnaire allowing for the collection of information necessary to document indicators could be proposed for inclusion in each type of design. Information regarding the context of HIV care and statistical data on the characteristics of case-loads across type of settings and regions are necessary to complement data collected at diagnosis on transmission categories, demographic characteristics, and progression of HIV.
Table 1 presents selected features of available methods for collecting behavioural surveillance data among PLWHA.
Table 2 presents the best two methods proposed by the experts for the situation in which the population is reachable in known settings.
Table 1. Selected features of available methods for collecting behavioural data among PLWHA
|Population representative designs|
In countries with concentrated or low epidemics, population surveys are not adapted to surveillance among PLWHA: no nominative registers, very small numbers in the general population
«Convenience», non-representative designs
|Venue-based surveys (a)||Practical, can be linked with an intervention||
Venues attended by PLWHA are medical settings or places run by NGOs which select segments of the PLWHA population
|Internet surveys (b)||Practical, possibility to reach many individuals||Internet allows HIV-infected MSM to be reached but will under- represent other populations, such as migrants and older patients|
Service-based surveys, two main types (c)
In most EU countries, people with known HIV infection receive care and most receive ARV treatment in special services in either hospitals or specialised medical practices
|Underrepresent people who interrupt treatment and care; Interviewing on beha-viour might be biased in the medical setting|
Is the best place to obtain diversi¬fied samples, since most PLWHA attend medical visits on a very regular basis
|Cross-sectional surveys among HIV+ individuals attending hospital settings (d)||
|Cohort studies (e)||
Examples (a) Venue-based surveysSpain: http://www.isciii.es/htdocs/centros/epidemiologia/epi_sida.jsp
(b) Internet surveysElford J, Bolding G, Davis M, Sherr L, Hart G. The Internet and HIV study: design and methods. BMC Public Health 2004;4:39.
(c) Service-based surveysPeretti-Watel P, Riandey B, Dray-Spira R, et al. (2005). Comment enquêter la population séropositive en France: l'enquête ANRS-EN12-VESPA 2003 [Surveying the HIV-Positive Population in France. The ANRS-EN12-VESPA 2003 Survey]. French. Population. 60, 4, 525-550.
(d) Cross-sectional surveys among HIV+ individuals attending hospital settingsGlass TR, Young J, Vernazza PL, Rickenbach M, Weber R, Cavassini M, et al. Is unsafe sexual behaviour increasing among HIV-infected individuals AIDS 2004;18(12):1707-14. Available at: URL: PM:15280782.
Elford J, Anderson J, Bukutu C, Ibrahim F. HIV in East London: ethnicity, gender and risk (2006). Design and methods. BMC Public Health, 9, 6, 150.
Hasse B, Ledergerber B, Hirschel B, Vernazza P, Glass TR et al.. Frequency and determinants of unprotected sex among HIV-infected persons: the Swiss HIV Cohort Study. Clinical Infectious Diseases 2010,51(11):1314-22
Thurnheer MC, Weber R, Toutous-Trellu L, Cavassubu M, Elzi L. Occurrence, risk factors, diagnosis and treatment of syphilis in the prospective Swiss HIV Cohort Study. AIDS, 2010, 24(12):1907-16.
(e) Cohort studiesDesquilbet L, Deveau C, Goujard C, Hubert JB, Derouineau J, Meyer L. Increase in at-risk sexual behaviour among HIV-1-infected patients followed in the French PRIMO cohort. AIDS 2002;16(17):2329-33. Available at: URL: PM:12441806.
The table below presents the best two methods proposed by the experts for the situation in which the population is reachable in known settings.
Table 2. Best methods to access PLWHA
|Method||Main indication for preference|
|Service-based cohort studies|
Most persons living with known HIV consult several times a year, whatever their social status or transmission group
|Service-based cross-sectional studies|
In countries where there are no cohorts or where cohorts do not include any behavioural information