Among 3647 MSM not using SMS prior to PS interview. Bold = p<0.05. Uptake and Impact of Short Message Service (SMS) Reminders via STI Partner Services (PS) on HIV/STI Testing Frequency among Men Who Have Sex with Men (MSM) Keshet Ronen1, Matthew R. Golden1,2, Julia C. Dombrowski1,2, Roxanne P. Kerani1,2, Teal R. Bell3, David A. Katz1,2 1 University of Washington, 2 Public Health – Seattle & King County, 3 Washington State Department of Health Contact: keshet@uw.edu Background Table 1. Characteristics of MSM offered SMS testing reminders through STI PS, 2013-2017 Table 2. Correlates of SMS testing reminder uptake STI PS are an opportunity to provide HIV/STI prevention interventions to high-risk MSM. Use of SMS testing reminders has been proposed as a means of increasing HIV/STI testing frequency, but limited data exist on its efficacy, especially from implementation in public health practice. In King County, WA, PS attempt to reach all MSM with early syphilis and those with gonorrhea or chlamydia as resources allow. Since July 2013, PS have offered quarterly SMS testing reminders to interviewed MSM. Among 3647 MSM not using SMS prior to PS interview. Bold = p<0.05. Univariable Multivariable RR (95% CI) Calendar year of diagnosis 0.57 (0.53-0.61) 0.59 (0.51-0.67) Age 10-24 Ref 25-34 0.62 (0.51-0.75) 0.81 (0.61-1.07) 35-44 0.48 (0.37-0.61) 0.65 (0.45-0.95) 45+ 0.42 (0.33-0.55) 0.56 (0.37-0.84) Race/ethnicity White Black 1.35 (0.99-1.83) 1.30 (0.85-2.00) Asian 1.50 (1.16-2.02) 1.27 (0.87-1.85) Latino 1.55 (1.28-1.89) 1.24 (0.91-1.70) Other 1.63 (1.20-2.20) 1.27 (0.80-2.04) STI Gonorrhea (no syphilis) Any syphilis 0.15 (0.08-0.29) 0.27 (0.13-0.57) Chlamydia only 1.38 (1.17-1.61) 1.50 (1.17-1.92) HIV status HIV-negative not on PrEP HIV-negative on PrEP 0.25 (0.17-0.38) 0.30 (0.19-0.46) HIV-positive 0.51 (0.39-0.67) 0.35 (0.25-0.49) Diagnosed by HIV/STD specialist 1.23 (1.03-1.47) 1.08 (0.84-1.39) Insured 0.52 (0.43-0.62) 0.77 (0.56-1.05) Used methamphetamine 0.91 (0.67-1.24) Used inhaled nitrates 0.15 (0.14-0.17) 1.04 (0.79-1.37) Injected drugs 1.05 (0.70-1.60) Number of sex partners in last year 1.00 (1.00-1.00) N n (%) or median (IQR) Age 3908   ≤24 1070 (27.4) 25-34 1611 (41.2) 35-44 771 (19.7) ≥45 756 (19.3) Race/ethnicity a 3883 White 2413 (62.1) Black 258 (6.6) Asian 282 (7.3) Latino 705 (18.2) Other 225 (5.8) STI 3909 Gonorrhea (no syphilis) 2255 (57.7) Any syphilis 431 (11.0) Chlamydia only 1223 (31.3) HIV status Negative 2968 (75.9) Previous positive 910 (23.3) Newly diagnosed positive 31 (0.8) PrEP user b 2429 743 (30.6) Diagnosed by HIV/STD specialist 2699 (69.1) Insured 3683 3088 (83.8) Used methamphetamine 3651 295 (8.1) Used inhaled nitrates 3658 964 (26.4) Injected drugs 3639 134 (3.7) Number of sex partners in last year 3406 6 (3-12) Objectives To evaluate level and correlates of SMS reminder uptake among all MSM interviewed by PS. To evaluate impact of SMS reminders on STI testing frequency among HIV-negative MSM. Methods Data from PS interviews in July 1, 2013 – January 17, 2018 were used. Starting in February 2014, clients who refused SMS reminders were asked if they used another type of reminder. Correlates of SMS acceptance among all MSM were identified by Poisson regression with robust standard errors. All variables associated in univariable analysis at p<0.1 we included in multivariable analysis. The impact of reminders on testing frequency was evaluated by comparing time from last HIV test to asymptomatic STI diagnosis among HIV-negative MSM by Mann-Whitney test. Asymptomatic STI was defined as rectal or pharyngeal chlamydia or gonorrhea, urethral chlamydia without symptoms, or early latent syphilis. For clients with multiple recorded PS visits at which they were offered SMS reminders, the first non-null response was included in this analysis. a Individuals of any race who identify as Latino are classified as Latino. All other groups are non-Latino. b Among HIV-negative Figure 1. Uptake of SMS and other testing reminders Table 3. Association between reminder use and STI testing frequency Uptake among 3909 MSM offered SMS Other reminder use among 2485 who refused Time from last HIV test to diagnosis of asymptomatic STI among HIV-negative MSM Summary n Months since last test Median (IQR) p-value SMS reminder * 167 4.8 (3.1-7.7) Ref Non-SMS reminder 715 3.6 (2.6-5.6) <0.001 Physical exam 50 9.6 (4.0-17.2) 0.003 No reminder 495 5.6 (3.3-10.7) 0.11 Unknown 488 5.1 (3.2-9.5) Offering SMS testing reminders by PS was feasible, but uptake was low. Uptake was associated with earlier calendar year of diagnosis, younger age, non-syphilis STI, HIV status and PrEP use. MSM employed diverse methods to remind themselves to test or integrate testing into primary care. MSM using non-SMS reminders had the shortest testing interval. SMS testing reminders may be a useful tool to support testing among young HIV-negative MSM who are not engaged in other services. * Includes SMS received via PS or through other means We thank the Public Health Seattle & King County (PHSKC) disease intervention specialists for their work conducting partner services as well as PHSKC epidemiology and data management staff for their work on the supplemental database. This program and its evaluation were supported by the CDC [H25 PS004364]; the Washington State Department of Health; and PHSKC. The evaluation was also supported by the NIH [P30 AI027757]. Other reminders: smartphone app, phone calendar, note to self