Quality of Care and Use of Pharmacologic Preventions for HIV in the United States

The human immunodeficiency virus (HIV) epidemic has been on-going for more than 40 years, since 1981.1 Within the United States, there were 1.2 million people living with HIV at the end of 2018 and there are over 30,000 new cases diagnosed annually.2 The first pharmacologic treatment for HIV positive individuals, zidovudine (AZT), was approved in 1987.3 Since then, not only have more medications been approved to treat HIV positive individuals, but also the indications for these medications have expanded as pharmacologic preventions for HIV negative patients. These include a post-exposure prophylaxis (PEP) regimen of HIV medication given to those that have had an exposure to HIV, and pre-exposure prophylaxis (PrEP), taken by those prior to engaging in activity that may cause an exposure.4-8 While there has been much research that characterizes the expansion of use of PrEP, there is limited evidence describing trends in PEP use.9-20 Additionally there has been little investigation related to PrEP prescribers adhering to recommended monitoring guidelines and examination of persistence and adherence to PrEP use nationally. Therefore, this dissertation seeks to investigate these gaps in the literature utilizing an analysis of existing healthcare resource utilization data. In Chapter 1, the background of the HIV epidemic and the demographics of those most at-risk of HIV seroconversion are explored at both the national and international levels. A review of PrEP is presented that specifically summarizes the clinical effectiveness, access barriers, clinical testing guidelines, and trends of use within the United States. Information is then presented about PEP, focused on non-occupational PEP (nPEP) including an overview of the treatment, the clinical effectiveness, and a summary of the literature examining utilization of PEP. In Chapter 2, the study described explores provider adherence to the clinical testing guidelines for PrEP prescribing. The objective was to examine if there were provider type differences in adherence to guidelines between primary care providers (PCPs) and infectious disease providers (IDPs), as well as those that have one PrEP patient versus those that have multiple. There were 4,200 providers identified in the data, prescribing PrEP to 29,660 patients from January 1, 2011 to December 31, 2019 in the Merative MarketScan data (the data used for all three studies). Overall, adherence to monitoring recommendations was low, with only 6.4% of providers having claims for >60% of recommended testing during an appropriate testing window. Concerningly for more than half of the providers there was not an HIV testing claim at initiation of treatment for any of their PrEP patients. In adjusted analyses, there was no association found between provider type and high quality care. However, providers with one PrEP patient were more likely to have high quality care compared to those that have multiple PrEP patients. These study findings suggest the important need of further training for providers and the possible implementation of interventions, such as automatic test ordering via electronic health records, to ensure high quality care is provided for patients. In Chapter 3, the results of national trends in adherence and persistence to PrEP are presented. The study had three objectives: 1) to describe adherence and persistence of PrEP among a national commercially insured cohort, 2) to compare adherence and persistence between males and females, and 3) to compare adherence and persistence between age groups. There were 29,689 PrEP users identified during the study period, 81.9% of whom were defined as adherent (>80% proportion of days covered (PDC) by PrEP medication before discontinuation). In adjusted analyses females and those <45 years of age were more likely to be adherent. In terms of persistence, more than half of individuals that initiate PrEP discontinue within their first year, with the median time to discontinuation being 238 days. In multivariable analyses that accounts for competing risks, males and those ≥45 years old were more persistent than their counterparts. This study shows that although there is high adherence among PrEP users, there is a need for better tools and reduction of barriers to ensure individuals are able to be persistent on PrEP to maintain the population-level HIV prevention benefits. In Chapter 4, trends of PEP use, specifically non-occupational PEP (nPEP) use, are summarized. Over the period from January 1, 2010 through December 31, 2019, there was an increase of 515% in the rate of nPEP use. Using joinpoint analysis, the rate of increase of nPEP use was largest from 2012 – 2015 and the rate of increase more moderate after 2016. This trend was more pronounced for 13-24 years old. Importantly, the groups with the highest rate of HIV incidence in the data were not those most likely to be using nPEP. This study provides evidence on nPEP use nationally and shows increased use of this key HIV prevention tool. However, certain groups may still face barriers to nPEP access that need to be removed. Lastly, in Chapter 5 the findings of these studies are summarized and the implications for HIV prevention are discussed. It also includes potential future research areas that are necessary to further fill in existing gaps in evidence.