6ER-023 Analysis of the incidence of sexually transmitted diseases in users of HIV-1 pre-exposure prophylaxis

<h3>Background and Importance</h3> HIV pre-exposure prophylaxis (PrEP) is a biomedical intervention for the prevention of HIV infection that is recommended by the World Health Organization. It includes a combination of tenofovir disoproxil fumarate and emtricitabine. <h3>Aim and Objectives</h3> To analyse and describe the incidence of sexually transmitted diseases in candidates for HIV-1 pre-exposure prophylaxis. <h3>Material and Methods</h3> Retrospective observational study from January 2021 to September 2024. All patients who initiated PrEP during the study period were included. Variables: age, sexual partners per year (&gt;10 or &lt;10); prophylactic use, drug use during sex, administration of post-exposure prophylaxis (PEP) prior to PrEP, number of PEP, infection of sexually transmitted diseases prior to PrEP (previous_STDs), number of previous_STDs, time since initiation of PrEP; number of consultations with the doctor, number of STDs after starting PrEP, type of microorganism causing STDs, treatment for STDs, adherence, treatment interruption and need for PEP after interruption. Results were analysed by descriptive statistics using STATA-MP17.0. <h3>Results</h3> 86 PrEP users were included, mean age=34 years (standard deviation (SD=9.64). All users were men who have sex with men, except for one woman in prostitution. 94% of users had &gt;10 sexual partners; 91% do not regularly use prophylactic, 32% use drugs in sex. Prior to starting PrEP 28% needed PEP with a mean frequency of 1.34 (SD=0.77) times. 60% were infected with an STD before PrEP, getting infected a mean of 1.7 (SD=1.03). The mean time on PrEP was 13 months (SD=10) and the mean number of consultations by a doctor was 4.4 (SD=2.7). The incidence of STD infection was 53.5%, the mean number of STDs was 1.06 STDs(SD=1.34), the difference in STDs compared to STDs before PrEP was not statistically significant, p=0.064. The causative agents of STDs were: 28%-Neisseria-gonorrhoeae, 23%-Treponema-pallidum, 16%-Chlamydia-trachomatis, 16%-Mycoplasma-genitalium, 10%-Human-Papilloma-Virus, 4%-Herpex-simplex, 3%-Monkeypox. The mean adherence rate was 91% (SD =16.5), 27% treatment discontinuations and 2% had to use PEP after the end of the PrEP. <h3>Conclusion and Relevance</h3> PrEP users have a high incidence of STDs, with Neisseria gonorrhoeae being the most common causative agent. However, comparison of STD incidences before and after starting PrEP shows no significant differences. <h3>Treatment adherence was high</h3> <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest