RT Journal Article SR Electronic T1 Social determinants of self-reported pre-exposure prophylaxis use among a national sample of US men who have sex with men JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP 368 OP 374 DO 10.1136/sextrans-2019-054177 VO 96 IS 5 A1 Chu, Brian A A1 Castellanos, Erick R A1 Gonzales, Manuel M A1 Gaither, Thomas W YR 2020 UL http://sti.bmj.com/content/96/5/368.abstract AB Purpose Various disparities exist in HIV transmission among men who have sex with men (MSM). Pre-exposure prophylaxis (PrEP) has been shown to decrease the acquisition of HIV, but there is variation in uptake within the MSM population. We aim to characterise PrEP use and correlates of self-reported PrEP use in a large national sample of urban MSM in the USA.Methods Using data from a geosocial-networking application, a national sample (n=3744) from the largest 50 metropolitan centres in the USA was obtained.Results We found 18.1% (95% CI 16.8 to 19.3) of profiles reported using PrEP, with decreased reported PrEP use in younger MSM aged 18–24 years (adjusted OR (aOR)=0.5, 95% CI 0.3 to 0.7), obese MSM (aOR=0.5, 95% CI 0.3 to 0.9), black MSM (aOR=0.6, 95% CI 0.4 to 0.9) and MSM in the South (aOR=0.7, 95% CI 0.5 to 0.9).Conclusion Significant disparities exist in PrEP reporting by age and among black, Southern US and obese MSM. More research is needed to better understand these disparities.