Background and Importance The United Nations General Assembly established that a fast response was required to end AIDS epidemics by 2030. Pre-exposure prophylaxis (PrEP) involves reducing the risk of acquiring HIV. However, a main apprehension exists with regard to risk compensation, concerning that PrEP decreases the condom use and increases sexually transmitted infections (STI). Similarly, to the aforementioned goal, by 2030, the WHO’s proposed a 90% reduction in the syphilis and gonorrhoea incidence. Regarding PrEPs increasing use, it is important to assess our standpoint and how to improve.

Aim and Objectives Characterise and assess the PrEP using population regarding demographics, adherence, STI prevalence and HIV infection.

Material and Methods Retrospective study of PrEP prescribed patients, between 2017–2022 (minimum 6-month period intake). Population characteristics, post-exposure prophylaxis history (PEP), PrEP regimen, adherence, therapeutic suspension and their causes, seroconversion and STIs (chlamydia, syphilis, gonorrhoea, trichomoniasis, Mycoplasma genitallium), were analysed and confronted with our country’s latest report of STI notification.

Results We analysed 392 patients (97% male; 91.7% male sex with male), with a medium age of 37 years, mainly from Portugal (52%) and Brazil (33.7%). Only 14.3% did PEP, meaning that 85.7% started PrEP straightaway. The majority (91.6%) were on a daily regimen. The STI prevalence was 73.4% (gonorrhoea 46.2% and chlamydia 38.3%). The Covid-19 pandemic had little effect on adherence, increasing PrEPs use (proportion days covered =82.8%). Only two patients tested positive for HIV. Suspension rate was 28.1% in which 50.5% of causes were traceable (four patients due to adverse effects).

Conclusion and Relevance PrEP demonstrated high tolerability and efficacy but had a big prevalence of STIs among PrEP users. Between 2015–2017 nationwide, 4819 cases of chlamydia, gonorrhoea, and syphilis were reported, comparing to 463 patients of a regional hospital, even acknowledging a wider period. Access difficulties might be the cause of high suspension rate, despite free supply. Hospitals are assuming an increasing burden of costs, leading to monthly supply of increasing patients, investing in HIV prevention but promoting STIs. We can engage with prescribers to start pharmaceutical appointments to promote behavioural changes concerning STIs and to educate for the need of maintaining PReP adherence. Simultaneously, we can give educational materials and health lectures.

Conflict of Interest No conflict of interest.