(P238-LB) Association of STI screening and prevalent STI cases in MSM at a Sexual Health Clinic

Background: Over the last 10-15 years, public health authorities have increasingly advocated for more frequent sexually transmitted infection (STI) testing in men who have sex with men (MSM). Whether this effort has affected the prevalence of STIs is unclear, and some authorities are now questioning the value of frequent screening. We assessed whether STI screening led to a decrease in prevalent STIs among MSM sexual health clinic (SHC) patients.



Methods: Clinical data collected during visits by MSM to a SHC in Seattle, WA, USA from 2015-2022 were included in this analysis. For each visit, we determined whether the patient had been screened at least once at the clinic in the previous 180 days for gonorrhea, chlamydia, and syphilis. At each visit, prevalent gonorrhea, chlamydia, and syphilis diagnoses were assessed through clinical test result data. We used generalized estimating equation models to evaluate the association of prior screening with STI outcomes, controlling for age, race, ethnicity, methamphetamine use in the past year, number of male sex partners in the past year, HIV status, and PrEP use.



Results: The analysis included 26,742 clinic visits by 8,285 MSM seen between 4/30/2015 and 4/29/2022. 9,329 (35%) of these clinic visits were for STI screening. MSM who were screened for STIs in the previous 180 days had an 18% lower risk of being diagnosed with an STI compared to MSM who were not screened in the previous 180 days (RR=0.82, 95% CI: 0.77-0.87). MSM who were screened in the previous 180 days had a 57% lower risk of syphilis (RR=0.43, 95% CI: 0.36-0.52), 16% lower risk of gonorrhea (RR=0.84, 95% CI: 0.78-0.91), and 13% lower risk of chlamydia (RR=0.87, 95% CI: 0.80-0.95) compared to those who were not screened. Screened men had a significantly lower risk of both symptomatic and asymptomatic STI and were at lower risk for rectal and pharyngeal GC/CT infections.



Conclusion: Our findings suggest that frequent STI screening decreases the prevalence of STI among MSM. The extent to which this impact justifies continued quarterly screening of MSM for syphilis, gonorrhea, and chlamydia is uncertain.