Assessing the Population-Level Prevention Effect of Emergency Department–Based HIV Testing in the United States: A Research Framework and Commentary

Abstract

The effect of highly active antiretroviral therapy in HIV/ AIDS care on patient-level morbidity and mortality is without question, and HIV counseling and testing is an essential step on the pathway to accessing such care. For these reasons, the Institute of Medicine has stated that HIV treatment is so essential it should become a public health entitlement program, and many individuals and organizations have promoted strategic expansion of HIV testing services. Less well defined is the effect expanded HIV testing in emergency departments (EDs) might have on HIV transmission in the United States at the population level. Hsu and Walensky carefully reviewed the literature on the cost-effectiveness of expanded HIV testing in EDs in the United States and found no full-scale cost-utility studies exactly on this point. In this commentary, I outline a framework for assessing the possible population-level impact of expanded HIV testing in EDs during a 1-year period and observe how the articles in this section of the special issue can provide key parameters for that framework. It has been estimated that there are 119.2 million ED visits annually in the United States. If we extrapolate from the study by Hudepohl et al, we might approximate that there are 3.178 ED visits per year per patients of these facilities. Taken together, these estimates suggest that roughly 37.5 million people visit EDs each year in the United States. The Kaiser Family Foundation has estimated that approximately 21% of people in the United States have been tested for HIV in the past year, leaving 79% not tested in the past 12 months. Hence, roughly 29.6 million visitors to EDs in the United States might not have been tested for HIV in the last year. Of course, this estimate of 21% may not be equally distributed across individuals visiting and not visiting EDs in the past year. In this issue, Hudepohl et al estimated that approximately 6.95% (11,502/165,512) of patients in the ED in their study were offered, agreed to, and actually received HIV testing. If we extrapolate this percentage and apply it to the 29.6 million ED patients not tested in the past year, we might see 2,058,965 such individuals tested in an ED HIV testing program similar to the one conducted by Hudepohl et al. The estimate of 6.95% m