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Data shows less than half of PrEP users keep taking it after 2 years

Real-world data from a large US chain of retail pharmacies show that only two in five people keep on taking pre-exposure prophylaxis (PrEP) for two years after starting, researchers at the department of behavioral sciences and health education, Rollins School of Public Health, Emory University, Atlanta, report.

Most studies of PrEP persistence have been for shorter periods of time, but it has been thought that if participants are retained past an initial period on PrEP, then they are more likely to stick with it. The new study does not support that.

The researchers analysed pharmacy fill records from a random sample of 7,148 people who started PrEP at a Walgreens branch in 2015 (perhaps one in ten US PrEP users). Data were collected for two years after starting the preventative treatment. PrEP persistence was defined as having at least 16 days of PrEP medication filled per month for at least three-quarters of the months (nine months in a year). The threshold of 16 days per month was chosen because dosing at least four days per week has been shown to offer substantial protection against HIV to men who have sex with men.

The vast majority of PrEP users were men (97%). Most were in their thirties or forties, and 80% had commercial insurance.

Over the first 12 months, 56% (4030/7148) were classified as persistent on PrEP.
Amongst those who were persistent in the first year, 63% (2521/4030) were persistent during months 13 to 24. Throughout the first 24 months, 41% (2951/7148) were persistent (i.e. they had prescriptions for 18 of the 24 months).

People have ‘seasons of risk’, so not all PrEP users would need to stay on PrEP for the full two years. “But this is unlikely to be the only factor accounting for such high levels of PrEP cessation,” the authors comment. “Such substantial behaviour modification to convert three-fifths of individuals initiating PrEP to be no longer PrEP eligible is highly unlikely.”

In multivariable analysis, male gender, being 25 years of older, having a co-pay of $20 or less, having commercial insurance, and attending a community-based specialty pharmacy from the national chain were associated with persistence.

Only 29% of people aged 18 to 25 stayed on PrEP throughout the two years. “Younger individuals may be more likely to experience challenges in a number of areas, including cost navigation, fear of disclosure due to use of parental insurance, limited experience with the healthcare system, and financial barriers,” comment the authors.

Comparable studies of PrEP persistence have not been conducted in settings with fewer financial and administrative barriers to accessing healthcare.

As individuals switching to a different pharmacy could be misclassified as discontinuing PrEP, the researchers conducted a sensitivity analysis which only included the 5,837 people who filled a prescription at the chain for something apart from PrEP, after the 24-month study period. This made little difference to the results, indicating that pharmacy switching is not an important factor.

Introduction: Persistence on preexposure prophylaxis for HIV prevention (PrEP) medication has rarely been reported for periods greater than one year, or in real‐world settings. This study used pharmacy fill records for PrEP users from a national chain pharmacy to describe persistence on PrEP medication over a two‐year period, and to explore correlates with PrEP medication persistence in a real‐world setting.
Methods: We analysed de‐identified pharmacy fill records of 7148 eligible individuals who initiated PrEP in 2015 at a national chain pharmacy. A standard algorithm was employed to identify TDF‐FTC use for PrEP indication. We considered three time periods for persistence, defined as maintaining refills in PrEP care: year 1 (zero to twelve months), year 2 (thirteen to twenty‐four months) and initiation to year 2 (zero to twenty‐four months). Individuals with 16 or more days of TDF‐FTC PrEP dispensed in a 1‐month period for at least three‐quarters of a given time period (e.g. nine of twelve months or eighteen of twenty‐four months) were classified as persistent on PrEP medication for the period.
Results: Persistence was 56% in year 1, 63% in year 2 and 41% from initiation to year 2. Individuals aged 18 to 24 had the lowest persistence, with 29% from initiation to year 2. Men had higher persistence than women, with 42% compared to 20% persistent from initiation to year 2. Individuals with commercial insurance and individuals who utilized a community‐based specialty pharmacy from the national chain also had higher persistence. Male gender, age >18 to 24 years, average monthly copay of $20 or less, commercial insurance, and utilization of a community‐based specialty pharmacy were positively associated in adjusted models with persistence in year 1 and from initiation to year 2; the same correlates, with the exception of utilization of a community‐based specialty pharmacy, were associated with higher persistence in year 2.
Conclusions: We found substantial non‐persistence on PrEP medication in both year 1 and year 2. Across the entire 2‐year period, only two out of every five users persisted on PrEP. Demographic, financial and pharmacy factors were associated with persistence. Further research is needed to explore how social, structural or individual factors may undermine or enhance persistence on PrEP, and to develop interventions to assist persistence on PrEP.

Kelsey C Coy, Ronald J Hazen, Heather S Kirkham, Ambrose Delpino, Aaron J Siegler

[link url=""]Aidsmap material[/link]
[link url=""]Journal of the International Aids Society abstract[/link]

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