Most people who were prescribed emtricitabine/tenofovir disoproxil fumarate (Truvada) as pre-exposure prophylaxis (PrEP) from 2012 to 2016 with commercial insurance continued to use the HIV biomedical prevention tool for at least one year, while PrEP users on Medicaid didn't last as long, a new study shows. The findings were presented at the 2019 Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle by researchers from the U.S. Centers for Disease Control and Prevention (CDC).
The study examined 7,599 total participants from two cohorts -- 7,250 PrEP users who were commercially insured and 349 PrEP users with Medicaid insurance -- all 18 to 64 years old. The selection criteria included the person being enrolled in insurance six months prior to starting Truvada and remaining insured six months after beginning Truvada use. The status of non-persistence would be waived under three specific circumstances. They included a person seroconverting to HIV positive or leaving their health plan, or if the end of the study occurred.
Most providers and advocates are used to talking about adherence to PrEP, and it is different from persistence. PrEP adherence is the frequency of daily use, while persistence describes the duration of continued, uninterrupted use. High persistence and adherence rates both help PrEP's effectiveness, but persistence helps describe whether someone is continuing their prescription, and it can help point to either changes in the user's behavior or challenges with the health care system that make persistent use of PrEP difficult. In this study, persistence was monitored by examining this group of 7,599 people and their initial PrEP prescription, then identifying when a 30-day gap between prescription refills had occurred. The research team then estimated the length of time from the expected refill date to the end of the prescription supply.
The differences in persistence between the insurance coverage types were stark. Researchers found 74.8% of the commercially insured group persisted on PrEP for 6 months, and 55.7% of them persisted for 12 months. The median persistence length was 14.5 months for the commercially insured group. Meanwhile, the Medicaid group's median persistence length was 7.6 months. Thirty-four percent, about 119 of the total of the Medicaid users, were still persistent at 12 months.
Within the commercially insured cohort, 98% were men, 97% lived in urban areas, and 61% were 25 to 44 years old. In the Medicaid cohort, 78% were men and 67% were 25 to 44 years old.
The periods of persistence were significantly lower for PrEP users identified as black, female, and/or 18 to 24 years old. In the Medicaid cohort, female PrEP users' persistence averaged 5.8 months, while men's averaged 8.4 months. Data show persistence increased with age. Younger PrEP users on Medicaid persisted for 4 months, compared to the 10 months observed in users aged 45 to 54 years. Users living in rural areas also showed lower persistence rates.
"Better understanding of PrEP persistence will help inform the design of programs and interventions to help overcome the challenges," Ya-Lin A. Huang, Ph.D., M.S., with the CDC Division of HIV/AIDS Prevention, told the CROI attendees.
The reasons for participants ending or suspending Truvada were not available to researchers. Judy Auerbach, Ph.D., with University of California at San Francisco, asked Huang during the question and answer period if CDC could do a similar study that answers why people aren't persisting on PrEP so that programs and providers can more quickly address those issues. Huang responded by stating that there are several demonstration projects trying to answer that question at a smaller scale.
The lower PrEP persistence rates for women and younger people may provide further opportunity for increased PrEP engagement strategies. Structural barriers such as insurance coverage, proximity to PrEP providers, unemployment, and access to childcare and transportation may preclude these two groups from reaching higher persistence and adherence. Commercial insurance is often tied to employer-sponsored coverage, which can have little impact on someone who is under- or unemployed. In addition, Medicaid eligibility is seeing a wave of increased barriers, such as work requirements and block grants.
"Our study findings underscore the need for interventions specifically designed for priority populations to support their PrEP persistence," Huang said.
These populations who are more likely to use Medicaid include black men who have sex with men (BMSM), transgender women, and persons younger than 24 years. Since Truvada for prevention passed U.S. Food and Drug Administration approval in 2012, PrEP uptake has been greatest among white men who have sex with men (MSM), with less uptake among black and Latino MSM. Race, geography, and socioeconomic status influence these outcomes as well. For instance, The CDC reports more black people could benefit from increased PrEP uptake. However, in this study, for people on Medicaid, the median persistence among black PrEP users was 4 months compared to 8.5 months for white PrEP users.
In the discussion after her presentation, Huang mentioned the CDC is pursuing another study on PrEP persistence that would include people who are uninsured or receiving PrEP through medication assistance programs.