Two multicenter research teams supported in part by the National Institute on Drug Abuse, National Institutes of Health, have independently determined through the development of computer models that routine screening for HIV in health care settings is as cost effective as screening for such other conditions as breast cancer and high blood pressure, and can provide important health and survival benefits. The studies also suggest that screening that leads to a diagnosis of HIV infection may further lower health care costs by preventing high-risk practices and decreasing virus transmission.
Both studies - one led by Dr. Gillian Sanders at Duke Clinical Research Institute at Duke University and Dr. Douglas Owens at the Veterans Affairs Palo Alto Health Care System; and one led by Dr. A. David Paltiel at Yale School of Medicine - are published in the February 10, 2005 issue of the New England Journal of Medicine.
"Of the nearly 1 million people in the United States infected with HIV, about 280,000 are unaware of their status," says NIDA Director Dr. Nora D. Volkow. "Current patterns of screening are inconsistent, and people generally are diagnosed late in their disease. There is the possibility that by expanding screening, people identified with HIV can begin highly effective and lifesaving medical therapy early on and improve their quality of life. And, by realizing their HIV status sooner, people may reduce high-risk behaviors and decrease transmission of this virus."
In the first study, the scientists developed a computer model to follow a hypothetical group of 43-year-old men and women whose HIV status was unknown, to estimate the health costs and benefits associated with voluntary HIV screening in health care settings.
"As part of the study, we analyzed the costs associated with HIV testing, counseling, followup, and treatment," says Dr. Sanders. "While no computer model is a perfect representation of reality, the results suggest that a one-time HIV screening program provides a very important health benefit and is a good value, even in populations with a relatively low proportion of people with HIV. In the end, a one-time screening costs about $15,078 for every year of life gained, a figure that takes into account the resulting reduction in virus transmission and benefits to partners."
"An intervention that costs under $20,000 per quality-adjusted life year gained would definitely be recognized as providing good value," notes Dr. Sanders. A quality-adjusted life year is a standard health outcome measure used by many researchers. It is a way to account for both longevity and health-related quality of life.
In addition, the researchers found that implementing a one-time screening program could reduce the annual HIV transmission rate over these patients' lifetimes by 21 percent compared to current practice.
In the second study, researchers developed a computer model that compared costs associated with HIV screening and current voluntary HIV diagnostic and counseling practices in three populations: a "high-risk" population in which 3 percent had undiagnosed HIV infection, a population in which 1 percent had undiagnosed HIV, and the general population in which the prevalence of undiagnosed HIV was 0.1 percent. They found that routine, voluntary HIV screening every 3 to 5 years provides clinical benefits and is cost effective in all but the lowest-risk populations. One-time screening in the general U.S. population also may be cost effective.
"Our study suggests that routine HIV counseling, testing, and referral should be extended," says Dr. Paltiel. "In populations barely meeting a 1 percent prevalence of undiagnosed HIV infection, the costs per quality-adjusted life year gained of HIV testing every 3 to 5 years compare favorably with those of many commonly used screening interventions in chronic conditions, including breast cancer, colorectal cancer, diabetes, and high blood pressure."
Data from other cost-effectiveness studies show that screening for type 2 diabetes costs approximately $56,600 per quality-adjusted life year gained, while screening costs for high blood pressure and colorectal cancer cost $48,000 and $51,200, respectively.
Further research might reveal the best ways to implement HIV screening programs, how to reduce existing barriers to screening, how to increase the effects of counseling on patient knowledge, and the cost-effectiveness of HIV screening in the elderly.
"These studies suggest that voluntary screening for HIV is justified in certain populations and may offer significant benefits on both clinical and cost-effectiveness grounds," says Dr. Volkow. "Additional research is needed to determine if one-time screening for undiagnosed HIV in the general population also is warranted."