Seek and treat: HIV update 2011
ABSTRACTAlthough mortality rates from human immunodeficiency virus (HIV) infection have declined dramatically in the United States, the incidence of new infections has not improved for more than a decade. The case is now strong for routine screening and early treatment of HIV infection to reduce transmission of the infection and to give patients an opportunity to live a reasonably healthy life. Clinicians in all health care settings should routinely and matter-of-factly test their patients for HIV infection, just as they screen for other diseases.
KEY POINTS
- Recommendations from the US Centers for Disease Control and Prevention call for routine HIV screening for all people ages 13 to 64 at least once regardless of their risk profile, and annual testing for people with known risk factors for acquiring HIV.
- Early treatment of HIV infection may reduce the risk of cancer, cardiovascular disease, neurocognitive disorders, and osteoporotic fractures and improve the rate of survival compared with patients treated late in the course of HIV infection.
- Finding and treating patients early in the course of infection has the potential to reduce infectivity in the community.
- Reliable rapid testing is now available to screen for HIV in community settings, emergency departments, and public health clinics, and during labor for those not tested in the prenatal period. It is also useful when follow-up is uncertain.
With early treatment of human immunodeficiency virus (HIV) infection, we can now expect patients to live a much longer life and, in some situations, have a near-normal lifespan.1 Unfortunately, in screening for HIV infection, the United States lags behind many regions of the world, and infection is often not diagnosed until patients present with advanced disease, ie, the acquired immunodeficiency syndrome (AIDS). In this country there is a critical need to make HIV screening a routine part of medical care in all health settings in order to give patients their best chance for a healthy life, to prevent mother-to-child transmission, and to reduce the spread of HIV in the community.
HIV infection meets the criteria that justify routine screening, as laid out by the World Health Organization2:
- It is a serious health disorder that can be detected before symptoms develop
- Treatment is more beneficial if begun before symptoms develop
- Reliable, inexpensive, and acceptable screening tests exist
- The costs of screening are reasonable in relation to the anticipated benefits.
This article will review the epidemiology of the HIV epidemic, present the benefits of early treatment, and make the case for widely expanding screening for HIV infection in the US health care system.
HIV INFECTION CONTINUES TO BE A LARGE BURDEN
In 2008, an estimated 33.4 million people worldwide were HIV-positive. The vast majority of infected people—more than 22 million—live in sub-Saharan Africa.3
The United States has approximately 1.2 million cases.4 Although this is a small proportion of cases worldwide, it still represents a significant health care burden. In this country, the number of AIDS cases peaked in 1993, and the rate of deaths from AIDS began to decrease over the ensuing years as adequate therapy for HIV was developed. Standard therapy then and now consists of at least three drugs from two different classes.
Unfortunately, we have made little progress on the incidence of this disease. The estimated number of new HIV infections in the United States in 2008 was 56,000 and had remained about the same over the previous 15 years.5,6 Because of improved rates of survival, the prevalence has risen steadily since the mid-1990s to the current estimate of 1.2 million persons living with HIV/AIDS in the US.
About 25% of people infected with HIV are unaware of it. This group accounts for more than half of all new infections annually, which highlights the importance of enhanced screening. Once people know they are infected, they tend to change their behavior and are less likely to spread the disease.7
HIV disproportionately affects minority populations and gay men
Cases of HIV infection are reported among all age groups, although most patients tend to have been infected as young adults. Currently, the largest age group living with HIV is middle-aged. As this cohort grows older, an increasing burden of comorbidities due to aging can be expected. In 5 years, about half of the people with HIV in this country are expected to be 50 years of age or older. Although survival rates have steadily increased due to better treatment, survival tends to be shorter for older people newly diagnosed with HIV.
Worldwide, about an equal number of men and women are infected with HIV, but in the United States infected men outnumber women. In this country, about half the cases of HIV transmission among adults are by male-to-male sexual contact, about 30% are by high-risk heterosexual contact (ie, with a partner known to be HIV-infected or at high risk for being infected), and about 10% are by injection drug use.
In the United States, AIDS is predominantly and disproportionately a disease of minorities and those who live in poverty. African Americans account for the largest number of cases, followed by whites and then by Hispanics. Combined, African Americans and Hispanics account for two-thirds to three-fourths of all new cases, although they make up less than one-fourth of the US population. The incidence rate is nearly 137 per 100,000 for African Americans, 56 per 100,000 for Hispanics, and 19 per 100,000 for whites. The incidence is highest in New York and in the southeast, the geographic areas where the greatest number of minorities and people living in poverty reside. These groups also often lack access to health care.
HIV TREATMENT IS MORE EFFECTIVE IF STARTED EARLY
Treatment guidelines from the US Department of Health and Human Services (DHHS) have changed over the years. When effective medications were first introduced in the 1990s, the trend was to treat everyone as soon as they were diagnosed. As the burden of therapy began to unfold (side effects, cost, adherence, and drug resistance), the consensus was to wait until the CD4 T-cell count dropped to a lower level. As the medications have improved and have become better tolerated, the pendulum has swung back to treating earlier in the course of the disease. Currently, the DHHS recommends that therapy be started at CD4 counts of 350 cells/mL or lower (level of evidence: A1).8 It also recommends therapy for CD4 counts between 350 and 500 cells/mL, but the level of evidence is lower.8
The CD4 T cell is the prime target of the HIV virus and also an important marker of the health of the immune system. The lower the CD4 count at the start of therapy, the more challenging it is to normalize.9 If HIV infection is diagnosed early and therapy is started early, the likelihood is higher of normalizing the CD4 count and preserving immune function.
Progress is being made toward diagnosing HIV earlier. The CD4 count at presentation is increasing, but patients in the United States still present for care later than in other countries. In 1997, the median CD4 count at presentation was 234 cells/mL; in 2007, it was 327 (normal is about 550–1,000). Although this is a significant improvement, more than 50% of patients still have fewer than 350 cells/mL at presentation, which is the current threshold for beginning therapy, according to the most recent guidelines.10
Before triple therapy was available, almost all HIV-infected patients died of AIDS-related diseases. Now, about half of treated HIV-infected patients in Europe and North America die of other causes.11 However, many diseases not previously attributed to AIDS are now also known to be exacerbated by HIV infection.
