Trends in Triple-Site Testing for Chlamydia and Gonorrhea in New York City: A Cross-sectional Study Using Health Information Exchange Data

Background: Sexually transmitted infections (STIs) pose a threat to public health and continue to rise in New York City (NYC) despite reductions in other parts of the United States. Chlamydia and gonorrhea can infect multiple anatomic sites, including the urogenital tract, pharynx, and rectum. Guidelines recommend multisite testing for select populations, yet multisite testing is not routinely performed, limiting our understanding of trends in positivity and missed infections. Methods: We conducted a retrospective cross-sectional study of patients who underwent triple-site testing for chlamydia and gonorrhea in NYC between January 2018 and June 2023 using data from Healthix, the largest public health information exchange (HIE) in the country. We examined rates of triple-site testing, the prevalence of positivity at any anatomic site, and the proportion of extragenital-only positivity. We fit logistic regression models using generalized estimating equations to identify predictors of triple-site testing as well as overall and extragenital-only positivity. Results: We identified 11,405 individuals who received triple-site testing during the study period, representing 28,565 triple-site tests, 2,742 chlamydia cases, and 2,702 gonorrhea cases. The rectum was the most common site of infection for both STIs. Overall, 82% of chlamydia infections (82% in men and 77% in women) and 86% of gonorrhea infections (86% in men and 87% in women) would have been missed with urogenital-only testing. Conclusions: In this cross-sectional study of HIE data, we examined citywide testing and found that, among patients undergoing triple-site testing, the majority of chlamydia and gonorrhea cases would have been missed through urogenital-only testing.