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Health services research
Original article
Who would use PrEP? Factors associated with intention to use among MSM in London: a community survey
  1. Adamma Aghaizu1,
  2. Danielle Mercey2,
  3. Andrew Copas2,
  4. Anne M Johnson2,
  5. Graham Hart2,
  6. Anthony Nardone1
  1. 1HIV and STI Department, Health Protection Agency—Colindale, London, UK
  2. 2Centre for Sexual Health & HIV Research, Department of Infection & Population Health, Mortimer Market Centre, University College London, London, UK
  1. Correspondence to Adamma Aghaizu, HIV and STI Department, Health Protection Agency—Colindale, London NW9 5EQ, UK; adamma.aghaizu{at}hpa.org.uk

Abstract

Objective To assess current and intended future use of pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) and characterise those attending sexual health clinics, the anticipated PrEP delivery setting.

Design Cross-sectional study.

Methods Self-administered survey of 842 HIV negative MSM recruited from social venues in London in 2011.

Results One in 10 (10.2%, 83/814, 95% CI 8.2% to 12.5%) and one in 50 (2.1%, 17/809, 95% CI 1.2% to 3.3%) reported having ever used post-exposure prophylaxis (PEP) and PrEP respectively. Half reported they would be likely to use PrEP if it became available as a daily pill (50.3%, 386/786, 95% CI 46.7% to 53.9%). MSM were more likely to consider future PrEP use if they were <35 years (adjusted OR (AOR) 1.57, 95% CI 1.16 to 2.14), had unprotected anal intercourse with casual partners (AOR 1.70, 95% CI 1.13 to 2.56), and had previously used PEP (AOR 1.94, 95% CI 1.17 to 3.24). Over half of MSM (54.8% 457/834 95% CI 51.3 to 58.2) attended a sexual health clinic the previous year. Independent factors associated with attendance were age <35 (AOR 2.29, 95% CI 1.68 to 3.13), and ≥10 anal sex partners in the last year (AOR 2.49, 95% CI 1.77 to 3.52).

Conclusions The concept of PrEP for HIV prevention in the form of a daily pill is acceptable to half of sexually active MSM in London. MSM reporting higher risk behaviours attend sexual health clinics suggesting this is a suitable setting for PrEP delivery.

  • HIV
  • Prevention
  • Prophylaxis
  • Gay Men
  • Antiretroviral Therapy

http://dx.doi.org/10.1136/sextrans-2012-050648

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    Introduction

    The HIV epidemic continues to grow and evolve and disproportionately affects men who have sex with men (MSM) in the UK. In 2010, there were an estimated 6600 new diagnoses of HIV of which nearly half (3000) were among gay men.1 A recent study has shown that the use of pre-exposure prophylaxis (PrEP) with ARV drugs may prevent infection with HIV in high risk MSM.2 In addition to clinical trials,3 further research is underway to assess the value of PrEP as a public health intervention.4–6 Understanding the acceptability of PrEP among its potential users is a necessary part of evaluating its feasibility as a public health tool.

    The Gay Men's Sexual Health Survey has been undertaken on an annual or biennial basis in community samples of MSM since 1996 and collects information on sexual behaviours, health service use and HIV antibody (Ab) status among MSM in selected UK cities. Using data from 2011, we examined the current level of use of ARVs for the prevention of HIV infection, and investigated factors associated with the likelihood of its future use among HIV negative MSM in London. Secondly, we explored the characteristics of MSM attending sexual health clinics, as this is the most probable setting for the future delivery of PrEP. Findings provide a community perspective on interest in this type of intervention, may guide the identification of participants for UK feasibility trials and may indicate the potential for future wider implementation of PrEP in the UK.

    Methods

    The Gay Men's Sexual Health Survey

    Since 1996, the Gay Men's Sexual Health Survey has been conducted 13 times. The methods of this survey have been described in detail elsewhere.7–9 Briefly, for the most recent year, between March and June 2011, a team of 18 trained fieldworkers recruited 1216 (response rate 62%) men in 31 London gay social venues such as bars, clubs and saunas. Participants self-completed an anonymous questionnaire on demographic characteristics, sexual behaviour and health service use and an Orasure saliva test (Orasure Technologies Inc, Bethlehem, Pennsylvania, USA) for anonymous HIV Ab testing. Eighty-two per cent of men (n=1005) who completed a questionnaire provided a saliva sample. New questions added to this year's survey examined experiences of the use of post-exposure prophylaxis (PEP) and experience and attitudes towards the use of PrEP.

    There was no difference in age, ethnicity, employment or education level between those who did and did not provide saliva samples, however those who did, were more likely to report having had a sexually transmitted infection in the previous year (16.8% vs 10.9%. p<0.05).

    Laboratory testing

    Within 3 weeks of collection, specimens were submitted to the Health Protection Agency for analysis. A two stage testing approach was applied by first screening with a modified enzyme immunoassay, (GACELISA HIV 1and 2, Abbott Laboratories, Maidenhead, UK) and second, re-screening positive specimens with an enzyme immunoassay and a western blot test (Genelabs HIV blot 2.2).

    Statistical analysis

    All questionnaire data were double entered in Microsoft Access 2007 and data cleaning and analyses performed in STATA V.12 (StataCorp, College Station, Texas, USA). The use of PEP was assessed by asking ‘Have you ever taken antiretroviral drugs after you had unprotected anal sex to reduce the risk of HIV infection (also known as post-exposure prophylaxis or PEP)?’ Similarly, we assessed the use of PrEP with ‘Have you ever taken antiretroviral drugs before you had unprotected anal sex, to reduce the risk of HIV infection (also known as pre-exposure prophylaxis or PrEP)?’ We investigated the likelihood of PrEP use asking ‘If PrEP were available, how likely is it that you would take a pill (oral dose) on a daily basis to prevent HIV infection?’ with a scale possible responses ‘very likely’, ‘likely’, ‘unlikely’, ‘very unlikely’ and 'don't know’.

    We excluded 26 questionnaires from men who were heterosexual, three from men who had completed the questionnaire previously and 62 from men who had never had sex with a man, leaving a total of 1125 questionnaires and 926 specimens (figure 1). Based solely on reports, 954 participants were HIV negative. Of those with samples (82%), test results revealed 1.6% (n=15) were HIV Ab positive. As PrEP would only be applicable to men who are HIV negative, we restricted the analyses to 842 men who tested HIV negative, examining attitudes and factors associated with the likelihood of PrEP use with bivariate and multivariate analyses using logistic regression. Variables which had a p value <0.2 in bivariate analyses were included in the multivariate model. For factors associated with attendance at sexual health clinics we examined age, ethnicity and all reported sexual behaviour characteristics relating to the previous year.

    Figure 1
    Figure 1

    Flow of participants through study.

    Results

    Respondent characteristics

    HIV negative participants had a mean age of 34.1 years, SD 9.2 years, range 18.5–71.5 and 18.0% (151/839) were of a non-white ethnic background. Most respondents were employed (86%, 720/835) and had more than 2 years of education post age 16 (93%, 777/833). Four of five respondents lived at an inner London postcode (78.4%, 660/842).

    Experience of PEP and PrEP and likelihood of future PrEP use in HIV negative MSM

    One in 10 respondents (10.2%, 83/814, 95% CI 8.2% to 12.5%) reported having ever used PEP. The unlicensed use of PrEP was rare with reports from only 2.2% (17/809, 95% CI 1.2% to 3.3%). However, when asked about intentions for future use, if PrEP were to become available as a daily pill, half of the participants said they were either very likely (34%, 261/768) or likely (16%, n=125) to use it. Fifteen per cent (n=115) reported unlikely, 26% (n=201), very unlikely and the remainder did not know (table 1).

    View this table:
    Table 1

    Associations between demographic and sexual behavioural characteristics and the likelihood of PrEP use among 768* HIV negative MSM†

    Factors associated with the likelihood of PrEP use in HIV negative MSM

    Participants were more likely to consider future use of PrEP in the form of a daily pill if they were under 35 years old, had had 10 or more partners in the previous year and had unprotected anal intercourse (UAI) and UAI with casual partners in the previous year (table 1). In the multivariate model, being younger than 35 years (adjusted OR (AOR) 1.57, 95% CI 1.16 to 2.14) and having had UAI with casual partners (AOR 1.70, 95% CI 1.13 to 2.56) remained independently associated with the likelihood of intended future PrEP use.

    The likelihood of reported intended future PrEP use among MSM was not significantly associated with a preference of setting for HIV testing when examining sexual health clinics and general practice (table 2). However, MSM who had experience of PEP were more likely to consider future use of PrEP than those that had not (AOR 1.96, 95% CI 1.17 to 3.26).

    View this table:
    Table 2

    Associations between reported sexual health and sexual health service use and the likelihood of PrEP use among 768* HIV negative MSM†

    Factors associated with sexual health clinic attendance among HIV negative MSM

    More than half of MSM (54.8%, 457/834 95% CI 51.3% to 58.2%) reported attending a sexual health clinic in the last year, with an average number of 2.4 (SD 1.7) visits over the year. Similar to the findings of the likelihood of PrEP use, bivariate analyses showed MSM who were aged less than 35 years, and had had 10 or more partners in the previous year were more likely to have attended a sexual health clinic within the last 12 months (table 3). In multivariate analyses, independent factors associated with sexual health clinic attendance were age less than 35 years (AOR 2.29, 95% CI 1.68 to 3.13) and 10 or more partners (AOR 2.49, 95% CI 1.77 to 3.50) in the previous year (AOR 1.57, 95% CI 1.16 to 2.13).

    View this table:
    Table 3

    Associations between demographic and sexual behaviour characteristics and reported sexual health clinic attendance in the previous year among 834 HIV negative MSM†

    Discussion

    Principal findings

    Among the London HIV negative male gay community, one in 10 MSM reported using PEP and one in 50 had ever used PrEP. The concept of ARV prophylaxis against HIV acquisition in the form of a daily pill would be acceptable to many as over half of all surveyed HIV negative MSM reported they would be likely to use PrEP if it were available. Younger MSM, those with experience of PEP, and importantly, those reporting higher risk behaviours such as UAI with casual partners were more likely to report willingness to use PrEP. Further, over half reported attending a sexual health clinic the previous year, the most probable setting for UK PrEP trials and PrEP distribution, with attendance rates higher among those reporting higher partner numbers.

    Comparisons with other studies

    The findings here are broadly consistent with other studies, most of which are set outside of the UK. The only other UK study to date was conducted among an internet panel of MSM who regularly participate in research surveys.10 Their findings were similar in that 52% would consider using PrEP if it were available in the form of a daily pill. Interestingly, they found no differences in the likelihood of PrEP use by age however MSM reporting regular and casual partners were more likely to consider its use. Other studies outside the UK, for example, by Liu et al11 among 1819 gay men in California, found that fewer than 1% had ever used PrEP and approximately two-thirds of respondents (67%, 95% CI 63% to 70%) would use PrEP daily if it were proven to be safe and effective. In the US, a study among 227 MSM in Boston had one report of off-label PrEP use and 74% of participants were willing to use PrEP in the future after being educated about its potential.12 Barash et al found that among 215 MSM recruited at an STD clinic and a gay pride event in Seattle, 44% reported that they would take PrEP every day to prevent HIV.13 Similarly, in France, 40% of MSM surveyed to take part in a PrEP trial were interested in taking part and reports of higher risk behaviours such as more than 20 partners in the previous 12 months and inconsistent condom use with casual partners were independently associated.4

    Few studies exist which compare the behaviour characteristics of MSM attending sexual health clinics with those that do not. However, in a study by Nardone et al,14 high risk sexual behaviour among MSM in London was associated with participants having been recruited from clinics as opposed to community settings.

    Strengths and weaknesses

    This study investigated the willingness to use ARV in the form of a daily pill as HIV prophylaxis among community-based, sexually active, HIV negative gay men recruited from social venues, including higher risk venues such as saunas and sex on premise venues. It provides an indication of the future acceptability of PrEP and information on the views of an urban-based sample of MSM, including those not regularly attending sexual health clinics. A broad definition of PrEP was given enabling generalisability of the findings and comparison with other studies. In addition, it provides insight on the sexual health service use of MSM likely to use PrEP in future and the characteristics of MSM attending sexual health clinics, the most probable PrEP delivery setting.

    The main limitation is that the survey was among a convenience sample and may not be representative; however, despite only including participants from London, it is one of the largest UK studies of hypothetical PrEP acceptability to date. Among those who had never heard of it, PrEP may have been misunderstood and confused with PEP. Further, no detail was given on possible side effects, costs and long-term efficacy which could influence the acceptability of this type of intervention. Thus, the values presented here could change with the availability of this information and increased awareness. However, all these aspects remain to be evaluated and defined for an intervention of this type.

    Implications

    It is unlikely that PrEP will be available to all MSM alone due to its current cost and the potential clinical and public health risks. A cost-effectiveness model using a base case model with a similar HIV prevalence in MSM to that in London (9%)15 estimated the annual cost of PrEP to be US$7536 per person.16 If PrEP were to become available, prioritising MSM at highest risk of acquiring HIV may be necessary.17 Further work will be needed to measure the cost per infection averted by ‘treating’ the uninfected in the UK, as has been done for a hypothetical HIV chemoprophylaxis programme among MSM in a US city.18

    Apart from the cost and effectiveness at individual level, the wider epidemiological impacts of PrEP must be evaluated prior its use as an intervention. For example, it is unclear what the overall impact of PrEP will be on transmission dynamics; HIV risk behaviour is high in this population as is incidence.1 ,19 It has been shown that PrEP has lower effectiveness with poor adherence.2 ,20 In addition, if coverage were low, or if it resulted in ‘risk compensation’ leading to increased risk behaviour, its overall impact may be low or could even increase transmission.

    Modelling studies have shown the inadvertent and or inconsistent use of PrEP in HIV infected individuals would be a major driver of ARV drug resistance.2 ,21 ,22 Data presented here show 1.6.% of those that thought they were HIV negative were positive, likely to be due to recent or incident infection. This figure could be higher since the test was unable to detect acute infections. Regular testing would need to be a key component of any PrEP intervention, as outlined by the Centre for Disease Control guidelines,23 ideally using fourth generation tests. Although a recent policy audit among a sample of 24 sexual health clinics in the UK found all to have fourth generation testing policy,24 it remains to be examined whether high risk MSM would adhere to the testing frequency required over longer periods.

    This study shows that PrEP is potentially acceptable to one in two MSM in the form of a daily pill. The acceptability of its use is not confined to high risk men, but importantly, younger MSM, those reporting UAI with casual partners and those with experience of PEP, who are at higher risk of acquiring HIV, are more likely to consider this as a prevention method. In addition, sexual health clinics are likely to be a suitable setting for the delivery of PrEP should higher risk MSM be selectively targeted.

    Key messages

    • If pre-exposure prophylaxis (PrEP) were to become available, one in two men who have sex with men (MSM) in London currently report that they would be likely to consider taking a pill on a daily basis to prevent infection with HIV.

    • MSM who were younger than 35 years, had unprotected anal intercourse with casual partners in the previous year, and had used post-exposure prophylaxis were more likely to consider future use of PrEP.

    • Over half of MSM reported attending a sexual health clinic in the previous year; more commonly reported among those aged <35 years, and having had 10 or more anal sex partners in the previous year, suggesting this could be a suitable setting for the delivery of PrEP.

    Acknowledgments

    We thank Gary Murphy and Bharati Patel for performing the laboratory testing and all participants for their valuable contributions. We also thank Dr Jonathan Elford for his advice on the wording for the PEP and PrEP questions.

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    Footnotes

    • Contributors All authors contributed to the design of the study. AA coordinated the data collection, and led the data management, analysis and drafting of the manuscript supported by DM, AC and AN. All authors commented on drafts of the manuscript and approved the final version.

    • Funding This study was funded by the Health Protection Agency.

    • Competing interests None.

    • Ethical approval Ethical approval was obtained from the UCLH Research Ethics Committee.

    • Provenance and peer review Not commissioned; externally peer reviewed.