National Sample Shows 40% of Patients Adhere to Full PrEP Schedule

Man holding a pill.
Man holding a pill.
Results showed substantial nonpersistence of PrEP for HIV prevention in both year 1 and 2, with only 40% of users adhering for the entire 2-year period.

Using data from a national pharmacy chain located in 49 states and 20 of the most populous cities, researchers found substantial nonpersistence of pre-exposure prophylaxis (PrEP) use for HIV prevention in both year 1 and year 2, with only 40% of users persistently using PrEP across the entire 2-year period. Findings from the study were published in the Journal of the International AIDS Society.

Despite ample evidence of the effectiveness of PrEP for HIV prevention with daily oral use of tenofovir disoproxil fumarate and emtricitabine in clinical trial settings, persistent PrEP use for periods >1 year or in real-world settings has rarely been reported. As such, researchers analyzed de-identified pharmacy fill records of individuals who initiated PrEP in 2015.

Persistence of PrEP use was defined as having at least 16 days of PrEP medication filled per 30-day period, starting at the index fill date, for at least three-quarters of a period (9 months in a 12-month period or 18 months in a 24-month period).

Of the 7148 individuals included in the study, 97% were men, >77% had a monthly PrEP copay of $20 or less, and 80% had commercial insurance. In addition, 35% of participants were between ages 30 to 39 years, 22% were age 25 to 29 years, 20% were age 40 to 49 years, 12% were age ≥50 years, and 11% were age 18 to 24 years.

In year 1, 56% were persistent PrEP users. Of the 4030 persistent users in year 1, 63% were persistently adherent to PrEP regimens in year 2. From initiation to year 2, 41% were persistent users. Participants aged 18 to 24 years had the lowest proportion of persistent PrEP use in year 1, year 2, and from initiation to year 2: 43%, 54%, and 29%, respectively. In addition, of PrEP users who were classified as not persistent at year 1, 12% would re-enter treatment and become persistent users in their second year of follow-up.

In multivariable analysis, male gender, age older than 18 to 24 years, having a copay of $20 or less, having commercial insurance, and attending a community-based specialty pharmacy were positively associated with persistence in year 1 and from initiation to year 2. With the exception of community-based specialty pharmacy use, these variables were also associated with higher persistence in year 2.

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Researchers noted that previously known factors such as financial barriers, poor tolerance of medication side effects, changes in perceived risk, limited social or external support, and difficulty adhering to frequent provider and laboratory visits likely contributed to the high levels of PrEP cessation.

One of the key limitations of the study was the researchers’ inability to isolate individuals who paid for PrEP using manufacturer’s medication or copay assistance programs into a separate category. Moreover, because the data were de-identified, key variables known to correlate with PrEP uptake and persistent use, such as race/ethnicity, gender identity, sexual orientation, and income, were not available.

In addition to considering regional variations of PrEP prescribing patterns and norms, future research should “explore how social, structural or individual factors may undermine or enhance persistence on PrEP medication, and develop and test interventions to assist persistence as indicated,” concluded the researchers.

Disclosures: Ronald J. Hazen, Heather S. Kirkham, and Ambrose Delpino are employees of Walgreen Co. Aaron J. Siegler is a co-investigator on a grant from the Gilead Foundation.


Coy KC, Hazen RJ, Kirkham HS, Delpino A, Siegler AJ. Persistence on HIV preexposure prophylaxis medication over a 2-year period among a national sample of 7148 PrEP users, United States, 2015 to 2017. J Int AIDS Soc. 2019;22(2):e25252.