Compared with HIV diagnosis patterns, the use of Truvada (tenofovir disoproxil fumarate/emtricitabine) as pre-exposure prophylaxis (PrEP) is particularly low among women, people younger than 25 and those living in the South. That is, according to the full published study of a research endeavor first presentedat the 2018 Conference on Retroviruses and Opportunistic Infections (CROI) in Boston that conducted a “PrEP-to-need ratio” analysis comparing breakdowns of current prescriptions of Truvada for HIV prevention with HIV diagnosis statistics.

Publishing their findings in the Annals of Epidemiology, researchers conducted a cross-sectional study of population-level data to compare the total number of current PrEP users during the fourth quarter of 2017 to the number of recent HIV diagnoses during 2016. This simple equation resulted in the PrEP-to-need ratio (PnR) figure, so that if the PnR were 2.0, in a given group, twice as many people would be using PrEP as had been diagnosed with HIV during the previous year.

The PrEP use data was culled from the national health data company Source Healthcare Analytics and relied on over 54,000 pharmacies, 1,500 hospitals, 800 outpatient facilities and 80,000 physician practices. The data set did not include PrEP prescriptions from either closed health care systems—such as Kaiser Permanente, a major source of such prescriptions in Northern California in particular—or those health care facilities that chose not to share data with the company.

During the third quarter of 2017, 70,395 people filled at least one PrEP prescription, according to the data set. The study authors estimated that the true number of PrEP users during this period was between that figure and 140,309 people. This compares with Gilead Sciences’ estimate that 153,000 people were using PrEP at that time.

The investigators looked to 2016 HIV diagnosis data from and U.S. population estimates derived from census data.

Nationally, the PnR was 1.8—there were that many PrEP prescriptions (70,395) in the third quarter of 2017 compared with HIV diagnoses in 2016 (40,183).

Broken down by region, the PnR was 3.3 in the Northeast, 2.4 in the Midwest, 2.1 in the West and 1.0 in the South. In states that expanded their Medicaid program under the Affordable Care Act, the PnR was 2.4, compared with 1.1 in states that did not expand. In states where Medicaid routinely covered HIV testing costs, the PnR was 2.1, compared with 1.1 in states that did not do so.

States in the highest quartile of residents living in poverty had a PnR of 1.0, compared with 2.1 among states in the lowest quartile. States in the highest quartile of residents without insurance had a PnR of 0.9, compared with 2.9 in states in the lowest quartile. States in the highest quartile concerning the proportion of their population that is African American had a PnR of 1.5, compared with 3.0 in states in the lowest quartile.

The study identified 3,229 female PrEP users and 67,166 male PrEP users, resulting in a PnR of 0.4 for females and 2.1 for males, a 5-fold difference. By age group, the PnR was 0.9 for those 24 years old and younger, 2.0 for those 25 to 34 years old, 2.2 for those 35 to 44 years old, 2.0 for those 45 to 54 years old and 1.5 for those 55 years old and older.

The states and territories with the highest PnR included Vermont (6.6), Washington (5.7), New York (4.2), New Hampshire (4.2), the District of Columbia (4.2), Minnesota (4.0) and Oregon (4.0). Those with the lowest PnR included Puerto Rico (0.1), South Carolina (0.5), Louisiana (0.6), Mississippi (0.6), Georgia (0.7), North Carolina (0.9), Arkansas (0.9), and Nevada (0.9).

“As programs seek to continue the scale-up of PrEP, disparities in coverage documented in this study should be addressed,” the study authors concluded. “Specifically, PrEP programs should target young individuals at high risk for HIV transmission, at-risk women of all ages and the Southern United States.”

To read the study, click here.