Abstract
Oral HIV pre-exposure prophylaxis (PrEP) is highly effective for preventing HIV. Several different developments in the US either threaten to increase or promise to decrease PrEP out-of-pocket costs and access in the coming years. In a sample of 58,529 people with a new insurer-approved PrEP prescription, we estimated risk-adjusted percentages of patients who abandoned (did not fill) their initial prescription across six out-of-pocket cost categories. We then simulated the percentage of patients who would abandon PrEP under hypothetical changes to out-of-pocket costs, ranging from $0 to more than $500. PrEP abandonment rates of 5.5 percent at $0 rose to 42.6 percent at more than $500; even a small increase from $0 to $10 doubled the rate of abandonment. Conversely, abandonment rates that were 48.0 percent with out-of-pocket costs of more than $500 dropped to 7.3 percent when those costs were cut to $0. HIV diagnoses were two to three times higher among patients who abandoned PrEP prescriptions than among those who filled them. These results imply that recent legal challenges to the provision of PrEP with no cost sharing could substantially increase PrEP abandonment and HIV rates, upending progress on the HIV/AIDS epidemic.