Introduction The municipal STD Clinic in Seattle, Washington provides PrEP to persons at high risk for HIV infection. Our objective was to determine the timing of and rationale for PrEP discontinuation among men who have sex with men (MSM) in the clinic.

Methods Two disease intervention specialists (DIS) coordinate the PrEP Clinic, assist patients with payment assistance program enrollment, remind patients of appointments, and manage a two way text message-based adherence support program. The DIS collect data for each patient at each visit in an electronic database. When patients stop PrEP, DIS assign a categorical reason for discontinuation. Patients are defined as lost to follow-up if they fail to attend a follow-up appointment and do not respond to a call, text message or letter. We reviewed the clinic database from 10/2014-12/2016 to evaluate the prevalence of and reasons for first PrEP discontinuation for each patient.

Results A total of 334 MSM agreed to start PrEP. Most were non-Hispanic white (52%), followed by Hispanic (24%), Asian or Pacific Islander (12%), and non-Hispanic black (8%). 27 men (8%) moved or transferred their care during the observation period. Of the remaining 307 men, 52 (17%) did not start PrEP and 81 (26%) discontinued PrEP at least once at a median time of 6 [interquartile range (IQR: 3–11)] months post-initiation for the following reasons: 53 (65%) lost to follow-up or unknown; 13 (16%) monogamous relationship with HIV-seronegative partner; 4 (5%) otherwise believed they were no longer at risk for HIV; 11 (14%) side effects. Race/ethnicity was not associated with discontinuation. Overall, the median observation time was 12 [IQR: 6–18] months. The prevalence of >1 discontinuation was 17% by 3 months (n=39/227), 26% by 6 months (45/174), 34% by 9 months (45/131), and 39% by 12 months (39/101). Of the 81 who discontinued, 5 (6%) restarted PrEP in our clinic a median of 6 months later.

Conclusions Patient attrition was most common prior to starting PrEP and occurred steadily thereafter. Few men restarted PrEP after discontinuation.