1529. Sexually-Transmitted Infection Testing and Positivity among Adults Receiving HIV Pre-Exposure Prophylaxis within an Integrated Health Care Delivery System in the United States

BACKGROUND: The goal of this project was to assess the frequency of sexually-transmitted infection (STI) testing and positivity among adult individuals initiating HIV Pre-Exposure Prophylaxis (PrEP) within Kaiser Permanente Northwest (KPNW). METHODS: We identified KPNW members, 18 years of age and older, who initiated PrEP (tenofovir+emtricitabine) between January 1, 2015 – December 31, 2018. Using data elements abstracted from the electronic health record system, we assessed demographic characteristics of those initiating PrEP and the rate of testing and positivity for HIV, chlamydia (CT) and gonorrhea (GC) and syphilis within a window around 120 days after PrEP initiation. RESULTS: Overall, 685 members initiated PrEP during our study period, 661 (96.5%) of whom were male. Mean and median ages were 38 and 36 years, respectively, with those 25-34 years of age comprising the highest proportion (241; 35.2%). The 460 PrEP initiators (67.2% of total) who continued use beyond 120 days were significantly older than those who discontinued use (39 vs. 36 years, p=0.0008). Among continuous users, 78.3% were tested for CT+GC and 83.9% were tested for syphilis roughly 120 days post-initiation, with positivity proportions of 6.9%, 6.7%, and 2.3%, respectively. Among those discontinuing, 39.6% were tested for CT+GC and 37.3% were tested for syphilis, with positivity proportions of 10.1%, 9.0%, and 2.4%, respectively. HIV testing was completed for 87.4% of continuous PrEP users and 40.9% of those who discontinued use; and we identified a total of three individuals who tested positive for HIV, all among the latter group. Manual chart review of these individuals confirmed that HIV exposure and infection occurred after PrEP discontinuation. CONCLUSION: We found high rates of STI testing among individuals receiving PrEP, in accordance with recommendations. Our findings of a lower STI prevalence among PrEP users is encouraging, although further work is required to assess the impact of differential testing rates and age between those who continue and discontinue PrEP use as well as reasons for PrEP discontinuation. Regular testing remains an important part of comprehensive PrEP care management and should continue to be encouraged to identify and treat STI among those at high risk for disease. DISCLOSURES: All Authors: No reported disclosures