The value of HIV screening in the United States in the era of effective treatment.

The US Preventive Services Task Force (USPSTF) recently released a draft recommendation for routine HIV screening in the general adult population under age 65 in the US, consistent with the 2006 Centers for Disease Control and Prevention (CDC) recommendations. The USPSTF draft assigns a grade A to this recommendation, which means that if it is adopted, most adults with public or private insurance coverage will be able to receive an HIV test without an out-of-pocket expenditure. The benefits of HIV screening include documented reductions in risk behavior among those who learn that they are HIV infected; earlier access to antiretroviral therapy, leading to avoidance of morbidity and mortality; and a potential 96% reduction in transmission of HIV to heterosexual partners among HIV-infected adults adhering to antiretroviral therapy. Results from models of HIV disease progression and treatment evaluating the cost-effectiveness of HIV screening in the US were part of the rationale CDC used to support expanding access to HIV testing, and these models continue to be used to evaluate different testing implementation strategies, although the USPSTF did not consider modeling studies in its recent evidence review. The majority of published analyses of the costeffectiveness of HIV screening in the US project the lifetime benefits and costs of earlier detection and entry into care for HIV-infected individuals and weigh these costs and benefits when calculating cost-effectiveness ratios; population benefits from reduced transmission are estimated as secondary benefits. Although including transmission benefits can result in more attractive cost-effectiveness ratios for screening interventions, the effects are attenuated by the additional time between the secondary infection event and the point in HIV disease progression where clinical symptoms emerge. Recently, Farnham and colleagues published a paper in Medical Decision Making arguing that HIV screening can be economically justified based solely on the benefit of HIV transmissions avoided attributable to sexual risk behavior change associated with the knowledge of being HIV infected. Their findings rely on 2 key parameters: the benefit of reduced sexual transmission by patients who newly learn of their HIV infection, and the lifetime cost and loss of qualityadjusted life-years avoided by preventing a secondary HIV infection. The annual transmission benefit that these authors derive from the literature is large, but they conservatively assume that the effect lasts for only 1 year and do not consider further transmission dynamics that may result in additional benefits depending on antiretroviral coverage and risk group. The lifetime cost avoided that they use was derived from previous work by this author and colleagues and may not be fully relevant in in the current situation. With the increasing success of antiretroviral treatment, HIV-infected individuals are living long enough to incur medical expenses for non-HIV conditions that they might have incurred in the absence of HIV, and there was no adjustment for the proportion of HIV care costs going to these conditions in the analysis by Farnham and colleagues. The impact of HIV screening on avoiding qualityof-life losses associated with HIV infection may also be diminished by more effective and less toxic HIV treatments. In the current issue of Medical Decision Making, Isogai and colleagues report the results of a health utility prediction model based on assessments completed by more than 800 HIV patients in Ontario, Canada, between 2007 and 2009. The authors’ final model included CD4 count (a measure Received 21 March 2013 from the Department of Public Health, Weill Cornell Medical College, New York, NY. Revision accepted for publication 4 April 2013.