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Research underscores the value of routine HIV screening, but barriers remain

In a major shift in policy, the Centers for Disease Control and Prevention (CDC) now recommends that providers carry out HIV screening as a routine part of medical care among adults and adolescents.

Statistics suggest that as many as 250,000 people—roughly one-quarter of the total number of HIV cases in the United States—are not aware of their HIV-positive status. With no knowledge of the risks involved, these individuals are undoubtedly passing the disease on to sexual partners. Further, they are failing to receive needed care for their disease.

Many HIV care experts applaud the new recommendations, but there is no question that huge obstacles stand in the way of routine HIV screening.

Funding is the biggest issue, but there are also legislative barriers and a clear need for new solutions on how to link HIV-positive patients with the counseling and care that they will need.

Research supports testing

New research published in the December 2006 Annals of Internal Medicine bolsters the case for routine testing by exploring some of the thorniest aspects surrounding the issue.1

“In its [new] guidelines, the CDC mentioned three big sources of uncertainty: how much HIV has to be in the population in order to justify expanded testing, how well the drugs have to work in terms of reducing transmission, and how much society is willing to pay for additional health,” says David Paltiel, PhD, the lead author of the research, and a professor in the Department of Epidemiology and Public Health at Yale School of Medicine in New Haven, CT. “We thought if those are the three basic uncertainties, then why don’t we explore what combination of them would result in something that would be a cost-effective use of money.”

To carry out their work, the researchers used a mathematical simulation model that Paltiel and his colleagues have been working with for more than a decade to predict the costs and benefits associated with different HIV care strategies. Called the Cost-Effectiveness of Preventing AIDS Complications Model (CEPAC), the tool simulates the events that occur in the life of an HIV-infected person. These include detection, treatment, medical costs, and transmission to others.

To date, researchers have used CEPAC to look at numerous issues ranging from the cost-effectiveness of antiretroviral therapy and when to start therapy, to the design of AIDS drug assistance programs.

In fact, researchers have used the CEPAC model to look at the value of HIV screening before, but they felt that new data and circumstances warranted further evaluation. “We previously found that HIV testing would be a cost-effective thing to do, but we changed the analysis here a little bit,” says Paltiel. “In the first place, we used updated cost and efficiency data, and secondly, this analysis focuses on rapid HIV testing, whereas the earlier research looked at conventional HIV testing.”

One other factor that distinguishes the new research from its predecessor is the extent to which researchers weighted the impact of a false-positive HIV test. In the earlier research, the researchers were criticized for not adequately taking this factor into account, so in the new analysis, Paltiel indicates that he and his coauthors went out of their way to account for the psychological and potentially economic and quality-of-life detriment of a false-positive test.

HIV testing offers good value

To look at the relative value of routine, rapid HIV screening, the CEPAC model figured in the additional costs of screening as well as the added years of survival based on earlier detection. It also took into account how much HIV infection shortens a person’s life.

Ultimately, researchers found that HIV testing would deliver better value than many diagnostic tests and procedures that physicians now do routinely, including screening for breast cancer, colorectal cancer, and diabetes.

“There are lots of things that we do in this country that are completely noncontroversial and completely routine that deliver quality-adjusted life years for a cost much higher than $50,000,” says Paltiel. “So, if I can show you that HIV testing delivers quality-adjusted life years for less than $50,000, I am simply making the case that compared to all these other things that we do as a matter of routine care, this seems to be delivering better bang for the buck.”

Investigators also looked at the impact of screening under a variety of scenarios where the amount that society is willing to pay for a quality-adjusted life year varies from $25,000–$100,000; the prevalence of HIV in the population varies; and the impact of drug treatment on transmission rates—an issue that remains unclear—can be manipulated as well.

“The less you are willing to pay for quality, then the more stringent you would be about making sure that there is enough HIV in the population, or that drug therapy is effective,” says Paltiel. However, he points out that even if the prevalence of HIV in the population is as low as 0.1%, and drug therapy has no impact on transmission rates, if society is willing to pay $75,000 for a quality-adjusted life year, then an expanded HIV testing program makes sense.

Rapid testing offers advantages

The model’s findings are based on the assumption that once people are identified as being infected with HIV, they will then be linked to good care. However, there is considerable doubt as to whether the funding and resources are currently available to provide this level of care to the many thousands of people who would be identified through routine HIV screening. Additionally, questions remain as to who is best equipped to carry out the screening tests, and to counsel patients about their results.

Rochelle Walensky, MD, MPH, a coauthor of the research into expanded HIV screening, and an infectious disease specialist at Massachusetts General Hospital in Boston, has been studying the feasibility of HIV testing for a number of years. For example, in 2005, she published the results of a nine-month pilot demonstration project, showing that routine, voluntary HIV screening in areas identified as having a high prevalence of HIV infection was effective at uncovering undiagnosed cases of HIV—even among people who considered themselves at low risk for contracting the disease.2

Researchers in that study conducted oral—but not rapid—tests at four urgent care centers, so patients needed to come back for a follow-up visit to receive their results. Walensky is now in the process of launching a four-year, randomized trial that will look at different strategies for using the rapid HIV test—a procedure that delivers a result within minutes, but it is a preliminary finding that must be confirmed with further testing.

Nonetheless, Walensky anticipates there will be more patients willing to undergo rapid testing. “Certainly the follow-up will be less of a problem for patients who test negative, but we will have to be vigilant in our follow-up of patients who test positive because these are only preliminary results,” she says, noting that the rapid test can produce some false-positive results. “Also, people who test negative must be told that there is a window period, and if they had any exposure within the last three months, the test will not pick that up.”

Barriers remain

Even with the rapid HIV tests and streamlined counseling procedures, Walensky says significant problems with routine testing remain. For example, she notes that the laws in several states require written informed consent in a patient’s chart before an HIV test can be administered. This is a labor-intensive process for medical personnel, and an obstacle to patients who might be reluctant to sign their name.

“I am a firm believer that we need to streamline the process of HIV testing to eliminate written informed consent, but I am also a firm believer that no one should be HIV tested without their knowledge and permission. So I think there has got to be some happy medium where the written informed-consent process is not such a barrier, and yet patients are fully informed,” Walensky says.

Further, if the CDC guidelines are to be fully carried out, then routine HIV testing must be offered in primary care settings. The test is relatively easy to administer, but what is not clear is whether PCPs are equipped with the time, resources, and training to provide appropriate counseling.

“There is literature suggesting that PCPs are uncomfortable discussing sexual risk, so it wouldn’t surprise me if that is one of the reasons why [routine HIV testing] is not taking place, but other reasons include 20-minute office visits and the pressure to see many patients, addressing all of their acute and prevention issues simultaneously,” says Walensky. “When you bring up HIV testing with a patient, it opens the door to a longer discussion that patients potentially want to have. And providers need to be prepared and equipped to have that discussion.”

In fact, Walensky suggests that PCPs may not be the ideal personnel to carry out HIV tests. She points out that social workers and health educators are well-equipped with the training and skills to provide counseling that is especially critical in the event of a positive test result. “There are HIV counselors [who provide HIV testing] in every state in the country, and maybe we should be thinking outside of the box about having a different mechanism to get this done,” she says.

References

1Paltiel D, Walensky R, Schackman B, et al. “Expanded HIV Screening in the United States: Effect on Clinical Outcomes, HIV Transmission, and Costs.” Annals of Internal Medicine 2006; 145:797–806.

2Walensky R, Losina E, Malatesta L, et al. “Effective HIV Case Identification Through Routine HIV Screening at Urgent Care Centers in Massachusetts.” American Journal of Public Health 2005; 95:71–73.