[Source: The Journal of the American Medical Association, full page: (LINK). Abstract, edited.]
Original Investigation / April 9, 2019
Association of HIV Preexposure Prophylaxis With Incidence of Sexually Transmitted Infections Among Individuals at High Risk of HIV Infection
Michael W. Traeger, MSc1; Vincent J. Cornelisse, MBBS, PhD2,3,4,5; Jason Asselin, BSc1; et al Brian Price, MBA2; Norman J. Roth, MBBS4; Jeff Willcox, MBBS6; Ban Kiem Tee, MBBS7; Christopher K. Fairley, MBBS, PhD3,5; Christina C. Chang, MBBS, PhD2,5; Jude Armishaw, BNurs2; Olga Vujovic, MBBS2; Matthew Penn, MBBS8; Pauline Cundill, BM8; George Forgan-Smith, MBBS9; John Gall, MBBS, PhD9; Claire Pickett, MBBS10; Luxi Lal, BPharm1,2; Anne Mak, BPharm2; Tim D. Spelman, MBBS, MSc1,11,12; Long Nguyen, MCom1; Dean A. Murphy, PhD13,14; Kathleen E. Ryan, PhD1,2; Carol El-Hayek, MEpi1; Michael West, BA15; Simon Ruth, MSSc16; Colin Batrouney, BA16; John T. Lockwood, BN2; Jennifer F. Hoy, MBBS2; Margaret E. Hellard, MBBS, PhD1,2,11; Mark A. Stoové, PhD1,11; Edwina J. Wright, MBBS, PhD1,2,12; for the PrEPX Study Team
Author Affiliations: 1 Disease Elimination Program, Burnet Institute, Melbourne, Victoria, Australia; 2 Department of Infectious Diseases, Alfred Health and Monash University, Melbourne, Victoria, Australia; 3 Melbourne Sexual Health Centre, Alfred Health, Melbourne, Victoria, Australia; 4 Prahran Market Clinic, Melbourne, Victoria, Australia; 5 Central Clinical School, Monash University, Melbourne, Victoria, Australia; 6 Northside Clinic, Melbourne, Victoria, Australia; 7 Centre Clinic, Thorne Harbour Health, Melbourne, Victoria, Australia; 8 PRONTO! Clinic, Thorne Harbour Health, Melbourne, Victoria, Australia; 9 ERA Health, Melbourne, Victoria, Australia; 10 Ballarat Community Health Centre, Ballarat, Victoria, Australia; 11 School of Public Health and Preventive Medicine, Monash University, Melbourne, Victoria, Australia; 12 The Peter Doherty Institute of Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia; 13 Department of Gender and Cultural Studies, University of Sydney, Sydney, New South Wales, Australia; 14 The Kirby Institute, University of New South Wales, Sydney, New South Wales, Australia; 15 Sexual Health and Viral Hepatitis Service, Department of Health and Human Services, Government of Victoria, Melbourne, Victoria, Australia; 16 Thorne Harbour Health, Melbourne, Victoria, Australia
JAMA. 2019;321(14):1380-1390. doi:10.1001/jama.2019.2947
- Question – Is the use of HIV preexposure prophylaxis (PrEP) associated with increased risk of sexually transmitted infections (STIs) among individuals at high risk of HIV infection?
- Findings – In this longitudinal study of 2981 mostly gay and bisexual men who received daily HIV preexposure prophylaxis, STI incidence was 91.9 per 100 person-years, with 736 participants (25%) accounting for 2237 (76%) of all STIs. Among 1378 participants with preenrollment STI testing data available, receipt of PrEP after study enrollment was associated with an increased incidence of STIs compared with preenrollment (adjusted incidence rate ratio, 1.12).
- Meaning – Findings suggest the importance of frequent testing for STIs among gay and bisexual men using PrEP.
Emerging evidence suggests that risk of bacterial sexually transmitted infections (STIs) increases among gay and bisexual men following initiation of HIV preexposure prophylaxis (PrEP).
To describe STI incidence and behavioral risk factors among a cohort of predominantly gay and bisexual men who use PrEP, and to explore changes in STI incidence following PrEP commencement.
Design, Setting, and Participants
The Pre-exposure Prophylaxis Expanded (PrEPX) Study, a multisite, open-label intervention study, was nested within the Australian Collaboration for Coordinated Enhanced Sentinel Surveillance (ACCESS) clinic network. A total of 4275 participants were enrolled (July 26, 2016–April 1, 2018) in Victoria, Australia. Of these, 2981 enrolled at 5 ACCESS clinics (3 primary care, 1 sexual health, and 1 community-based HIV rapid testing service), had at least 1 follow-up visit, and were monitored until April 30, 2018.
Upon enrollment, participants received daily oral tenofovir disoproxil fumurate and emtricitabine for HIV PrEP, quarterly HIV and STI testing, and clinical monitoring.
Main Outcomes and Measures
The primary outcome was incidence of chlamydia, gonorrhea, or syphilis. Incidence rates and hazard ratios describing behavioral risk factors of STI diagnosis were calculated. Incidence rate ratios (IRRs), adjusted for change in testing frequency, described changes in STI incidence from 1-year preenrollment to study follow-up among participants with preenrollment testing data (n = 1378).
Among the 2981 individuals (median age, 34 years [interquartile range, 28-42]), 98.5% identified as gay or bisexual males, 29% used PrEP prior to enrollment, 89 (3%) withdrew and were censored at date of withdrawal, leaving 2892 (97.0%) enrolled at final follow-up. During a mean follow-up of 1.1 years (3185.0 person-years), 2928 STIs were diagnosed among 1427 (48%) participants (1434 chlamydia, 1242 gonorrhea, 252 syphilis). STI incidence was 91.9 per 100 person-years, with 736 participants (25%) accounting for 2237 (76%) of all STIs. Among 2058 participants with complete data for multivariable analysis, younger age, greater partner number, and group sex were associated with greater STI risk, but condom use was not. Among 1378 participants with preenrollment testing data, STI incidence increased from 69.5 per 100 person-years prior to enrollment to 98.4 per 100 person-years during follow-up (IRR, 1.41 [95% CI, 1.29-1.56]). After adjusting for testing frequency, the increase in incidence from 1 year preenrollment to follow-up was significant for any STI (adjusted IRR, 1.12 [95% CI, 1.02-1.23]) and for chlamydia (adjusted IRR, 1.17 [95% CI, 1.04-1.33]).
Conclusions and Relevance
Among gay and bisexual men using PrEP, STIs were highly concentrated among a subset, and receipt of PrEP after study enrollment was associated with an increased incidence of STIs compared with preenrollment. These findings highlight the importance of frequent STI testing among gay and bisexual men using PrEP.
Keywords: HIV/AIDS; Antivirals; PrEP; STIs; Australia.