Adherence to daily HIV pre-exposure prophylaxis in a large-scale implementation study in New South Wales, Australia

Restarting pre-exposure prophylaxis (PrEP) for HIV: a systematic review and meta-analysis

Background

High coverage of pre-exposure prophylaxis (PrEP) will reduce HIV transmission and help end the HIV/AIDS pandemic. However, PrEP users face challenges, including long-term adherence. The study aimed to document the proportions of individuals who restart HIV PrEP after they stop and the reasons for restarting PrEP.

Methods

This study is a systematic review and meta-analysis. We systematically searched CINAHL, Embase, Emcare, Global Health, Medline, Scopus, and PsychINFO for peer-reviewed with no date restrictions. A grey literature search was conducted through Google search, a search of abstract books of AIDS conferences and the websites of WHO and UNAIDS. The data search was conducted in April 2023 and updated in February 2024. Two authors extracted data on the proportion of people who stopped and then restarted PrEP, reasons for restarting, and strategies to support people restarting PrEP. Two authors appraised the data using the Joanna Briggs Institute Appraisal Tools. We used a random-effects meta-analysis to pool estimates of restarting. We conducted meta-regression to determine potential sources of heterogeneity. This study is registered with PROSPERO, CRD42023416777. However, we deviated from our original plan as we did not identify enough studies for strategies to support restarting PrEP (primary objective). Subsequently, we revised our plan to strengthen our secondary objective to quantify the proportion of people who stopped and restarted PrEP, and explore possible reasons for its heterogeneity.

Findings

Of 988 studies, 30 unique studieswere included: 27 reported the proportion restarting PrEP, and of these, 7 also reported reasons for restarting PrEP, and 3 studies reported only on the reasons for restarting PrEP. No study evaluated interventions for restarting PrEP. For the meta-analysis, we included 27 studies. Most studies were from high-income countries (17/27, 63%) or the USA (15/27, 56%). Overall, 23.8% (95% CI: 15.9-32.7, I2 = 99.8%, N = 85,683) of people who stopped PrEP restarted PrEP. There was a lower proportion of restarting in studies from middle-income countries compared to high-income countries (adjusted odds ratio (aOR) 0.6, 95% CI: 0.50-0.73, p < 0.001). There was higher restarting in studies from Africa compared to the USA (aOR 1.55, 95% CI: 1.30-1.86), heterosexual populations compared to men who have sex with men or transgender women (aOR 1.50, 95% CI: 1.25-1.81, p < 0.001) and in studies defining restarting as those who had stopped PrEP for >1 month compared to those who stopped <1 month (aOR 1.20, 95% CI: 1.06-1.36, p < 0.001). Reasons for restarting PrEP included perceived higher risk for HIV acquisition and removal of barriers to access PrEP. In terms of quality assessment, overall, both randomised controlled trials had a low risk of bias, while the observational studies used in the meta-analysis had some potential risk of bias related to not explicitly addressing potential confounders (15/25, 60%) or not describing strategies to address incomplete follow-up (24/25, 96%).

Interpretation

About a quarter of people who stopped PrEP would restart, with substantial variation across countries and populations. It is important to understand the motivations and contextual factors influencing restarting PrEP and the support systems to enable restarting PrEP for those at ongoing risk.

Funding

Australian National Health and Medical Research Council.

Incidence and factors associated with PrEP discontinuation in France

OBJECTIVES

HIV pre-exposure prophylaxis (PrEP) is effective in preventing HIV, but some seroconversions occur due to poor adherence or PrEP discontinuation. Our objective was to estimate the incidence of PrEP discontinuation and describe the reasons and factors associated with discontinuations.

METHODS

A retrospective cohort was conducted in three French hospitals between January 2016 and June 2022. PrEP users who attended at least twice within 6 months during study period were included and followed up until December 2022. The incidence rate of PrEP discontinuation was estimated by censoring lost to follow up individuals. Factors associated with PrEP discontinuations were identified using a multivariate Cox model.

RESULTS

A total of 2785 PrEP users were included, with 94% men and 5% transgender people. Median age was 35 years. By December 2022, 653 users had stopped PrEP (24%). The incidence rate was 10.8 PrEP discontinuations for 100 person-years (PY). The main causes of discontinuation were being in a stable relationship (32%), and not judging the treatment useful anymore (12%). Individuals who discontinued PrEP were younger [<29, HR = 1.45 (1.17-1.80)], and more likely to be women [HR = 2.44 (1.50-3.96)] or sex workers [HR = 1.53 (0.96-2.44)]. They were more likely to report PrEP side effects [HR = 2.25 (1.83-2.77)] or ≥2 sexually transmitted infections [HR = 1.87 (1.53-2.27)] during the last year.

CONCLUSION

The incidence of PrEP discontinuations was quite low compared to rates observed in other cohorts. Users who stopped PrEP were sometimes still exposed to HIV, emphasizing the need for targeted interventions to prepare and support PrEP discontinuations and limit seroconversion risk.

Trajectories of Pre-exposure Prophylaxis Adherence Among Commercially Insured Individuals

We used group-based trajectory models to identify 4 distinct trajectory patterns of adherence to preexposure prophylaxis (PrEP) among 20 696 users. Only 44.5% were consistently PrEP adherent, with younger age, being female, or having substance use disorder or depression associated with early discontinuation. Public health efforts are needed to improve PrEP adherence.

Determinants of adherence to daily PrEP measured as intracellular tenofovir diphosphate concentrations over 24 months of follow-up among men who have sex with men

OBJECTIVES

Adherence is key to the effectiveness of oral pre-exposure prophylaxis (PrEP) to prevent HIV. Therefore, we aimed to explore factors associated with adherence to daily PrEP (dPrEP).

METHODS

Men who have sex with men (MSM) using dPrEP (emtricitabine/tenofovir disoproxil) within the Amsterdam PrEP demonstration project at the Public Health Service of Amsterdam, provided dried blood spots (DBS) 12 and 24 months after PrEP initiation. From DBS, we determined intracellular tenofovir diphosphate (TFV-DP) concentrations to assess adherence; TFV-DP ≥700 fmol/punch was considered adequate. We assessed associations of sociodemographic, clinical and behavioural characteristics with TFV-DP concentrations using multivariable linear regression.

RESULTS

Of 263 participants who attended 12-month or 24-month study visits while on dPrEP, 257 (97.7%) provided DBS at one or both visits (492 DBS in total). Median TFV-DP concentration was 1299 (IQR 1021-1627) fmol/punch (12 months: 1332 (1087-1687); 24 months: 1248 (929-1590]). Higher TFV-DP concentrations were associated with: older age (p=0.0008), condomless anal sex with a casual partner in 6 months preceding PrEP initiation (+166 fmol/punch; 95% CI 36.5 to 296) and using a mobile application providing visualised feedback on PrEP use and sexual behaviour (+146 fmol/punch; 95% CI 28.1 to 263). Lower TFV-DP concentrations were associated with longer duration of PrEP use (24 vs 12 months; -91.5 fmol/punch; 95% CI -155 to -28.1). Time-updated number of sex partners, diagnosed STIs and chemsex were not associated with TFV-DP concentrations.

CONCLUSIONS

Overall, TFV-DP concentrations were high among MSM using dPrEP, indicating excellent adherence. Especially older participants, those who reported condomless anal sex with a casual partner prior to PrEP initiation and those who used an app with visualised feedback showed higher levels of adherence. As TFV-DP concentrations had decreased slightly at 2 years of PrEP use when compared with 1 year, we emphasise the importance of adherence counselling to those who continue using PrEP.

TRIAL REGISTRATION NUMBER

NL5413.

Longitudinal patterns of initiation, persistence, and cycling on preexposure prophylaxis among female sex workers and adolescent girls and young women in South Africa

OBJECTIVE

Female sex workers (FSW) and adolescent girls and young women (AGYW) face a disproportionately high risk of HIV in South Africa. Oral preexposure prophylaxis (PrEP) can avert new infections, but its effectiveness is linked to consistent use. Early discontinuation of PrEP in this population is high, but less is known about longitudinal patterns of PrEP use, including patterns of re-initiation and cycling.

DESIGN

Longitudinal descriptive analysis of routine program data.

METHODS

Between 2016 and 2021, 40 681 FSW and AGYW initiated PrEP at TB HIV Care, the largest PrEP provider to this population in South Africa and were included. Using survival analyses and group-based trajectory modeling, we described patterns of initiation, discontinuation, re-initiation, and cycling.

RESULTS

Total initiations increased over the life of the program for both FSW and AGYW. About 40% of FSW [0.41, 95% confidence interval (CI) [0.40-0.42]] and AGYW (0.38, 95% CI [0.37-0.38]) remained on PrEP at one month. FSW were more likely to restart PrEP, however <10% restarted PrEP within a year of initiation. Three latent trajectory groups of PrEP use were identified for FSW (low use, early cycling, and ongoing cycling) and two for AGYW (low use and ongoing cycling). Persistence was negatively associated with initiation among AGYW, but there was no clear relationship among FSW. Those initiating later in the program and older women had a reduced risk of discontinuation.

CONCLUSIONS

Persistence on PrEP was low, but cycling on and off PrEP was common, with early missed visits and inconsistent, but ongoing use. A push to increase PrEP initiations needs to factor in readiness and persistence support, to achieve public health impact.

Characteristics of Human Immunodeficiency Virus (HIV) Seroconversions in a Large Prospective Implementation Cohort Study of Oral HIV Preexposure Prophylaxis in Men Who Have Sex with Men (EPIC-NSW)

BACKGROUND

Most human immunodeficiency virus (HIV) seroconversions in people who have initiated preexposure prophylaxis (PrEP) occur in the context of insufficient adherence. We describe participants who seroconverted after being dispensed PrEP in a large PrEP implementation study in Australia.

METHODS

Expanded PrEP Implementation in Communities in New South Wales was an implementation study of daily oral PrEP in individuals aged ≥18 years at high risk for acquiring HIV. HIV seroconversions were defined as a positive HIV test by either antigen, antibody, or detectable HIV viral load after enrollment. Insufficient adherence, measured by dispensing logs or participant self-report, was defined as <4 PrEP doses per week.

RESULTS

A total of 9596 participants were enrolled and dispensed PrEP between 1 March 2016 and 30 April 2018; 30 were diagnosed with HIV by 31 March 2019. The median (interquartile range [IQR]) age was 31 (25-38) years, all identified as male, 29 (97%) identified as gay or homosexual, and 20 (69%) lived in a postcode with a low concentration of gay male residents. The median (IQR) days from first PrEP dispensing to diagnosis was 409 (347-656). There was no evidence that participants who seroconverted had been sufficiently adherent to PrEP. Nineteen (63%) participants who seroconverted were diagnosed with chlamydia, gonorrhoea, syphilis, or new hepatitis C infection. One participant had resistance to emtricitabine (M184V mutation) at diagnosis.

CONCLUSIONS

Participants who seroconverted were insufficiently adherent to PrEP despite being at high risk for acquiring HIV. Understanding the reasons for poor PrEP adherence in individuals who subsequently acquire HIV is critical to improving PrEP effectiveness.

Same-day initiation of oral pre-exposure prophylaxis among gay, bisexual, and other cisgender men who have sex with men and transgender women in Brazil, Mexico, and Peru (ImPrEP): a prospective, single-arm, open-label, multicentre implementation study

BACKGROUND

Although gay, bisexual, and other cisgender men who have sex with men (MSM) and transgender women have the highest HIV burden in Latin America, pre-exposure prophylaxis (PrEP) implementation is poor. We aimed to assess the feasibility of same-day oral PrEP delivery in Brazil, Mexico, and Peru.

METHODS

Implementation PrEP (ImPrEP) was a prospective, single-arm, open-label, multicentre PrEP implementation study conducted in Brazil (14 sites), Mexico (four sites), and Peru (ten sites). MSM and transgender women were eligible to participate if they were aged 18 years or older, HIV-negative, and reported one or more prespecified criteria. Enrolled participants received same-day initiation of daily oral PrEP (tenofovir disoproxil fumarate [300 mg] coformulated with emtricitabine [200 mg]). Follow-up visits were scheduled at week 4 and quarterly thereafter. We used logistic regression models to identify factors associated with early loss to follow-up (not returning after enrolment), PrEP adherence (medication possession ratio ≥0·6), and long-term PrEP engagement (attending three or more visits within 52 weeks). This study is registered at the Brazilian Registry of Clinical Trials, U1111-1217-6021.

FINDINGS

From Feb 6, 2018, to June 30, 2021, 9979 participants were screened and 9509 were enrolled (Brazil n=3928, Mexico n=3288, and Peru n=2293). 543 (5·7%) participants were transgender women, 8966 (94·3%) were cisgender men, and 2481 (26·1%) were aged 18-24 years. There were 12 185·25 person-years of follow-up. 795 (8·4%) of 9509 participants had early loss to follow-up, 6477 (68·1%) of 9509 were adherent to PrEP, and 5783 (70·3%) of 8225 had long-term PrEP engagement. Transgender women (adjusted odds ratio 1·60, 95% CI 1·20-2·14), participants aged 18-24 years (1·80, 1·49-2·18), and participants with primary education (2·18, 1·29-3·68) had increased odds of early loss to follow-up. Transgender women (0·56, 0·46-0·70), participants aged 18-24 years (0·52, 0·46-0·58), and those with primary education (0·60, 0·40-0·91) had lower odds of PrEP adherence. Transgender women (0·56, 0·45-0·71), participants aged 18-24 years (0·56, 0·49-0·64), and those with secondary education (0·74, 0·68-0·86) had lower odds of long-term PrEP engagement. HIV incidence was 0·85 per 100 person-years (95% CI 0·70-1·03) and was higher for transgender women, participants from Peru, those aged 18-24 years, Black and mixed-race participants, and participants who were non-adherent to PrEP.

INTERPRETATION

Same-day oral PrEP is feasible for MSM and transgender women in Latin America. Social and structural determinants of HIV vulnerability need to be addressed to fully achieve the benefits of PrEP.

FUNDING

Unitaid, WHO, and Ministries of Health in Brazil, Mexico, and Peru.

TRANSLATIONS

For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Discontinuation of government subsidized HIV pre-exposure prophylaxis in Australia: a whole-of-population analysis of dispensing records

INTRODUCTION

HIV pre-exposure prophylaxis (PrEP) has been government subsidized in Australia since April 2018 and while uptake is high among men who have sex with men, rates of discontinuation are also high. The aims of this study were to examine the impact of discontinuation on overall PrEP usage, the proportion of PrEP users who discontinue and the predictors of discontinuation.

METHODS

We used linked de-identified dispensing records of all government subsidized PrEP in Australia between April 2018 and September 2021: a whole-of-population data set. Defining discontinuation as 180 days or more without PrEP after the final dispensed supply, we calculated the number of people who discontinued at each 6-month interval during the study period, the proportion who had discontinued 2 years after the first supply and, using Cox regression, predictors of discontinuation.

RESULTS

Of 49,164 people dispensed PrEP (98.5% male, median age 34 years), 40.3% (19,815) had discontinued by September 2021. Within 2 years of their first supply, 11,150 (37.7%) of 29,549 PrEP users had discontinued, including 10.0% after a single dispensed supply. Large variations were observed, particularly according to prescriber characteristics: discontinuation was higher among people prescribed PrEP by low caseload (≤10 patients) prescribers (61.2%) than by high caseload (>100 patients) prescribers (31.1%, p<0.001), and by prescribers practising in areas with low estimated prevalence (<1.0%) of gay men (64.1%) than high (>5%) prevalence (36.7%, p<0.001). Women and younger people were more likely to discontinue, while patients receiving a higher level of government subsidy were less likely. The independent predictors of discontinuation with the greatest effect size were female sex (adjusted hazards ratio [aHR] 2.99, p<0.001), low estimated gay prevalence of prescriber location (aHR 1.98, p<0.001) and low prescriber PrEP caseload (aHR 1.79, p<0.001).

CONCLUSIONS

There are high rates of PrEP discontinuation in Australia and some populations are at increased risk of discontinuation. Strategies are needed to support persistence on PrEP and the re-starting of PrEP during periods of risk.

Travestis, transgender women and young MSM are at high risk for PrEP early loss to follow-up in Rio de Janeiro, Brazil

INTRODUCTION

Oral pre-exposure prophylaxis (PrEP) with emtricitabine/tenofovir (FTC/TDF) is highly effective in preventing HIV infection. This study aimed to identify factors associated with PrEP early loss to follow-up (ELFU) among gay, bisexual and other men who have sex with men (MSM), travestis and transgender women (TGW).

METHODOLOGY

This was a prospective cohort study evaluating TGW and MSM who initiated PrEP at the Evandro Chagas National Institute of Infectious Diseases (INI-Fiocruz) from 2014 to 2020. ELFU was defined as not returning for a PrEP visit within 180 days after first dispensation. Exposure variables included age, gender, race, education, transactional sex, condomless anal intercourse [CAI] (both in the past six months), binge drinking and substance use (both in past three months) and syphilis diagnosis at baseline. Multilevel logistic regression models with random intercepts and fixed slopes were used to identify factors associated with ELFU accounting for clustering of participants according to their PrEP initiation study/context (PrEP Brasil, PrEParadas, ImPrEP and PrEP SUS).

RESULTS

Among 1,463 participants, the median age was 29 years (interquartile range 24-36), 83% self-identified as MSM, 17% as TGW, 24% were black, 37% mixed-black/pardo and 30% had < 12 years of education. Fifteen percent reported transactional sex, 59% reported CAI, 67% binge drinking, 33% substance use, and 15% had a syphilis diagnosis. Overall, 137 participants (9.7%) had ELFU. Younger age (18-24 years) (adjusted odds ratio [aOR] 1.9, 95%CI:1.2-3.2), TGW (aOR 2.8, 95%CI:1.6-4.8) and education < 12 years (aOR 1.9, 95%CI:1.2-2.9) were associated with greater odds of ELFU.

CONCLUSION

TGW, young individuals and those with lower education were at higher risk of PrEP ELFU. Our results suggest that the development of specific strategies targeting these populations should be a priority, through policies that aim to reduce the incidence of HIV infection.

Between- and Within-Individual Sociodemographic and Psychological Determinants of PrEP Adherence Among Men Who have Sex with Men Prescribed a Daily PrEP Regimen in Wales

We investigated the determinants of daily PrEP use and coverage of condomless anal sex (CAS) by PrEP among men who have sex with men in Wales, UK. We measured PrEP use by electronic monitors and CAS by secure online surveys. We defined PrEP use based on daily medication cap openings and coverage as CAS episodes preceded by ≥ 3 days of PrEP use and followed by ≥ 2 days of PrEP use. We included 57 participants (5463 observations). An STI diagnosis was associated with lower PrEP use but also lower PrEP coverage. Older adults had higher PrEP use. A belief that other PrEP users took PrEP as prescribed was associated with lower PrEP coverage. An STI diagnosis is an important cue for an intervention, reflecting episodes of high-risk sexual behaviour and low PrEP coverage. Other results provide a basis for the development of an evidence-informed intervention for promoting coverage of PrEP.

Scaling up preexposure prophylaxis to maximize HIV prevention impact

PURPOSE OF REVIEW

Ten years since the first regulatory approval of oral HIV preexposure prophylaxis (PrEP), this review summarizes PrEP uptake, the role of ambitious PrEP targets, emerging evidence of impact on the HIV epidemic and innovative approaches to increasing PrEP uptake.

RECENT FINDINGS

PrEP uptake among people at risk of HIV has been slow, but has accelerated in recent years, particularly in gay and bisexual men in a limited number of high-income settings and recently in heterosexuals at risk of HIV in sub-Saharan Africa. However, UNAIDS 2020 PrEP targets and HIV prevention targets were missed by large margins. Although UNAIDS testing and treatment targets have galvanised public health action, in contras, PrEP targets have been lower profile and insufficiently ambitious. Parts of the USA, Australia and the UK with high PrEP coverage have demonstrated striking reductions in HIV infection at the population level, as PrEP is introduced at scale. Scaling up PrEP uptake will require innovations in PrEP promotion, simplified models of care, improved adherence interventions, improved choice in the form of longer-acting PrEP and interventions to ensure that all those who can benefit from PrEP can access it.

SUMMARY

PrEP is a revolutionary HIV prevention tool, which if ambitiously scaled up could drive HIV transmission towards elimination. Highly publicized and ambitious PrEP targets could help drive this.

Promises and challenges: cabotegravir for preexposure prophylaxis

PURPOSE OF REVIEW

Tenofovir-based oral PrEP has been effective in reducing population-level HIV incidence in multiple settings, although disparities remain. Injectable cabotegravir-based PrEP is an alternative that may be attractive to individuals with adherence challenges or who do not desire to take a daily medication. We review promises and challenges of cabotegravir-based PrEP.

RECENT FINDINGS

Cabotegravir has demonstrated higher effectiveness than oral PrEP in two randomized trials, with a hazard ratio of 0.31 for HIV incidence among MSM and transgender women across multiple settings [95% confidence interval (CI) 0.18-0.62] and 0.11 for cisgender women in sub-Saharan Africa (95% CI 0.040.32). Cabotegravir was also highly effective among populations with disproportionate HIV incidence. Although cabotegravir breakthrough was rare, diagnosis was delayed with use of antigen/antibody-based HIV tests, and resistance occurred with breakthrough infections. Implementation will need to overcome several challenges, including HIV RNA laboratory monitoring not being widely available, requirement for additional staff time and clinic space, and need to provide oral medication during interruptions in dosing.

SUMMARY

Cabotegravir-based PrEP is a highly effective additional PrEP option that will expand HIV prevention options. For successful roll-out, strategies for streamlined and accessible delivery of cabotegravir in real-world settings will need to be developed.

Running with Scissors: a Systematic Review of Substance Use and the Pre-exposure Prophylaxis Care Continuum Among Sexual Minority Men

Purpose of Review

Patterns of sexualized drug use, including stimulants (e.g., methamphetamine) and chemsex drugs, are key drivers of HIV incidence among sexual minority men (SMM). Although pre-exposure prophylaxis (PrEP) mitigates HIV risk, there is no consensus regarding the associations of substance use with the PrEP care continuum.

Recent Findings

SMM who use substances are as likely or more likely to use PrEP. Although SMM who use stimulants experience greater difficulties with daily oral PrEP adherence, some evidence shows that SMM who use stimulants or chemsex drugs may achieve better adherence in the context of recent condomless anal sex. Finally, SMM who use substances may experience greater difficulties with PrEP persistence (including retention in PrEP care).

Summary

SMM who use stimulants and other substances would benefit from more comprehensive efforts to support PrEP re-uptake, adherence, and persistence, including delivering behavioral interventions, considering event-based dosing, and providing injectable PrEP.

Pre-Exposure Prophylaxis (PrEP) Adherence Questionnaire: Psychometric Validation among Sexually Transmitted Infection Patients in China

BACKGROUND

Ensuring adherence guarantees the efficacy of pre-exposure prophylaxis (PrEP).

METHODS

We conducted a cross-sectional study among 816 sexually transmitted infection (STI) patients in Shanghai. The questionnaire included self-reported demographic characteristics, self-administered items on adherence to free oral PrEP, and PrEP uptake behavior measurement. We conducted item analysis, reliability analysis, validity analysis and receiver operating characteristic (ROC) curve analysis.

RESULTS

Not all items were considered acceptable in the item analysis. The questionnaire had a McDonald's ω coefficient of 0.847. The scale-level content validity index (CVI) was 0.938 and the item-level CVI of each item ranged from 0.750 to 1. In exploratory factor analysis, we introduced a four-factor model accounting for 79.838% of the aggregate variance, which was validated in confirmatory factor analysis. Adding PrEP adherence questionnaire scores contributed to prediction of PrEP uptake behavior (p < 0.001) in regression analysis. The maximum area under the ROC curve was 0.778 (95% IC: 0.739-0.817).

CONCLUSION

The PrEP adherence questionnaire presented psychometric validation among STI patients.