Forecasting the Effect of Out-of-Pocket Cost Changes for HIV Medication


Health Affairs study investigates the consequences of patient medication abandonment surrounding oral HIV pre-exposure prophylaxis.

Image Credit: Adobe Stock Images/

Image Credit: Adobe Stock Images/

In order to reduce the risk of contracting HIV, healthcare providers (HCPs) often prescribe oral HIV pre-exposure prophylaxis (PrEP); however, challenges persist in the areas of adherence, persistence, and uptake, which negatively impact overall PrEP use among at-risk populations.

The Centers for Disease Control and Prevention (CDC) estimates that there are currently 1.2 million adults in the United States whom PrEP is indicated for, but in 2021 alone, less than one-third of those adults actually received a PrEP prescription.

A study published in Health Affairs1 set out to investigate this phenomenon, which as the authors note, has been an ongoing obstacle to overcome, even after many private and state Medicaid plans are covering PrEP; a growing number of private health insurers having actually expanded coverage for it. Consequently, a major barrier to access has been patient out-of-pocket (OOP) spending, due to what are known as cost-sharing requirements, including coinsurance, copayments, and deductibles.

In order to conduct this study, investigators pulled 2015-2019 data from ICON’s Symphony Health Integrated DataVerse, containing both medical and pharmacy claims for over 274 million US patients. Via the National Council for Prescription Drug Programs, they were able to access individual-level patient data that represents 80%–85% of all HIV PrEP prescription claims in the United States.

Using the September 30, 2016–June 2, 2018, timeframe, the sample size consisted of 58,529 patients with an insurer-approved PrEP prescription for tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), which are marketed under the brand names Truvada and Descovy. Those with an eligible claim for PrEP were identified via a multistep process that included an algorithm that the authors had previously published.

As a way to distinguish the use of TDF/FTC for HIV PrEP, versus treatment of HIV, postexposure prophylaxis, or hepatitis B virus (HBV), they only included individuals who had a claim of TDF/FTC with a supply of more than 28-91 days; they also did not have any Ninth Revision, International Classification of Diseases, or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10), diagnosis codes for HIV or HBV; and no claims for HIV medications during the year before or 30 days after the index prescription.

The authors conducted several forms of analysis to determine abandonment status, including:

  • Multinomial logistic regression models to predict adjusted rates of HIV PrEP prescription abandonment versus paid fills, which were powered by multiple OOP categories.
  • Two logistic regression models were implemented to forecast the adjusted rates for the binary outcomes of abandonment of the index PrEP prescription; the HIV diagnosis or medication must have been had within one year after the index date.
  • The investigators also ran a simulation to determine the ways that PrEP prescription abandonment could be impacted at different tiers of OOP costs.

Out of the participating 58,529 patients with a new insurer-approved HIV PrEP prescription, results indicated that 13.5% abandoned their index prescription, while 88.8% of patients were male. Overall, 59.2% of patients had OOP costs for a 30-day prescription of $10 or less, while 11.4% of patients had OOP costs greater than $100.

Across all of the OOP cost classifications, HIV incidence was found to be higher for individuals who stopped filling their PrEP prescription, compared to those who filled it (6.1% versus 2.1% with cost sharing of $0; 4.9% versus 2.2% with cost sharing of >$0 to ≤$10; 3.9% versus 1.9% with cost sharing of >$10 to ≤$25; 3.6% versus 2.% with cost sharing of >$25 to ≤$100; 4.4% versus 2.2% with cost sharing of >$100 to ≤$500; and 4.6% versus 2.5% with cost sharing of >$500).

What does this mean exactly? If patients paying OOP for their PrEP prescription were to theoretically face a small increase in spending ($10 or less in this case), their abandonment rate would nearly double, going from an observed rate of 5.6% (95% confidence interval: 5.2, 6.0) to a predicted rate of 11.1% (95% confidence interval: 10.7, 11.5). And as the OOP costs rise, so does the abandonment rate.

Overall, the study investigators concluded that, “Our analysis of data from more than 58,000 newly prescribed PrEP patients in the US found that higher out-of-pocket costs were associated with an increased rate of patient abandonment of insurer-approved PrEP prescriptions. Further, within each out-of-pocket cost category, the rate of a new HIV diagnosis during a one-year follow-up was nearly two- to threefold higher among those who abandoned their index PrEP prescription relative to those who did not.

“…Our study results highlight the critical need for federal and state policy makers to identify strategies to ensure no-cost or low-cost access to PrEP with the goal of preventing widespread abandonment of PrEP medications and sacrificing the progress made in combating the HIV epidemic during the past thirty years in the US. Ongoing research and monitoring of upcoming policy developments and legal challenges will be needed to assess their effect on access and adherence to PrEP.


1. Dean LT, Nunn AS, Chang HY, Bakre S, Goeldel WC, Dawit R, Saberi, P, Chan PA, Doshi, JA. Estimating The Impact Of Out-Of-Pocket Cost Changes On Abandonment Of HIV Pre-Exposure Prophylaxis. Health Affairs. January 2024.

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