Aging and human immunodeficiency virus (HIV) infection were once considered mutually exclusive conditions. Older people did not “get AIDS” (acquired immunodeficiency syndrome) and the younger people who did never had a chance to grow old. Now, thanks to the success of combination antiretroviral therapy (CART), people aged 50 years and older represent a growing proportion of all those living with HIV infection; from 2001 to 2004, the proportion grew from 17% to 23%. The U.S. Senate Subcommittee on Aging now predicts that by 2015, 50% of the U.S. population living with HIV infection will be 50 years of age or older.

As the prevalence of HIV infection grows in older population groups, the risk of new HIV infections is also likely to increase. This increased risk may be exacerbated by several factors. First, the use of sildenafil (Viagra) and related medications to effectively treat erectile dysfunction and enhance sexual performance may increase risky sexual behavior. Additionally, postmenopausal women may be less likely to request that condoms be used as they face no risk of pregnancy. Finally, age-associated erectile changes may make condom use difficult and age-associated declines in immunity may place older individuals at higher risk of transmission with each exposure.

Research in age, aging, and HIV has focused on comparing outcomes among persons aged 50 years and older to their younger counterparts. This cut point is supported in HIV for both sociological and medical reasons: people aged 50 years and older with HIV state they feel marginalized because of age and this group experiences a shortened survival and greater burden of comorbid disease. Additionally, some data suggests that chronic HIV infection causes an accelerated aging process; an HIV infected 50-year-old person may have more physiologically in common with an uninfected individual aged 60 or 70 years.

While few geriatricians are likely to choose to manage antiretroviral agents, geriatricians need to be aware of the new Centers for Disease Control and Prevention recommendations for HIV screening. Geriatricians will also be increasingly needed to comanage the effects of aging and cumulative frailty; comorbid medical and psychiatric conditions; and drug interactions and toxicities in people with HIV infection. Further, the study of HIV infection among aging individuals may provide a template for improving the management of complex chronic disease more generally especially among special populations of aging individuals—people of color, sexual minorities, those with few socioeconomic resources, and those aging with heavy substance use histories. These groups are often ignored or understudied when more common conditions of aging are addressed.

Little is known about the presentation of acute HIV infection in older patients. In younger patients, acute infection may be completely asymptomatic or present as a flu-like syndrome. Like older HIV-negative individuals, older people with HIV infection underreport symptoms as compared to younger individuals, and this underreporting may be especially pronounced in older black patients. In addition, the symptoms associated with HIV infection are also common among older patients without HIV infection.

Among those persons 50 years of age and older who are chronically infected with HIV and in care, the most common self-reported symptoms are fatigue, pain in hands or feet (peripheral neuropathy), problems sleeping, muscle or joint pain (myalgias or arthralgias), and problems with having sex. Prior to the start of antiretroviral therapy, people with HIV infection tended to have lower cholesterol values than demographically matched controls. Common laboratory abnormalities include leucopenia, anemia (predominantly normocytic), and transaminitis. Thus, unless the clinician has a high index of suspicion in the older patient, or routinely screens for HIV infection, it may be difficult to identify HIV-positive individuals. HIV-infected women enter menopause at a median age of 46 years compared to the median of 51 years among uninfected women. HIV-infected women also tend to experience more pronounced symptoms during menopause. Hypogonadism is also prevalent among men infected with HIV. Like the symptoms, signs, and laboratory abnormalities discussed above, most of the diagnoses made in older people with HIV are not unique to HIV infection.

Physicians and their older patients are likely to underestimate the risk of HIV infection. The patient may be misinformed or in denial. The physician may mistakenly believe that the patient is not having unprotected sex with multiple partners or using illicit drugs. Nationally, the median CD4 cell count at presentation for HIV care continues to indicate advanced HIV disease (counts below 200 per mm3) and delayed treatment. This is especially true among older individuals.

Because untreated individuals are more likely to infect others, the benefit from treatment is less among those presenting with advanced disease and previous targeted screening policies have not improved the situation. The Centers for Disease Control and Prevention have revised their guidelines for HIV testing as of September of 2006 to encourage near universal screening. Specifically, current recommendations now call for HIV screening among:

• All patients aged 13 to 64 years in all health care settings
  
• All patients initiating treatment for tuberculosis
  
• All patients seeking treatment for sexually transmitted diseases
  
• All persons at high risk for HIV (at minimum on a yearly basis)

The Centers for Disease Control and Prevention goes further to say that opt-out screening (screening after notifying the patient that an HIV test will be performed unless the patient declines) is now recommended in all health care settings. Specific signed consent for HIV testing should not be required. General informed consent for medical care should be considered sufficient to encompass informed consent for HIV testing.

Regardless of age, any patient reporting any of the following: multiple sexual partners and unprotected sex; a prior diagnosis of a sexually transmitted disease (gonorrhea, syphilis, chlamydia, or trichomonas); or illicit drug use is at high risk for HIV infection and should be tested. Note that in some cases, an individual in a monogamous relationship may present with a sexually transmitted disease because their partner has more than one partner. These individuals are at risk for HIV as well and should be tested. While, intravenous drug use is a risk factor in itself; illicit drug use, IV or otherwise, is associated with risky sexual behavior. Hazardous alcohol use is also an important risk factor for unprotected sex with multiple partners. Because older patients may not spontaneously report these behaviors and conditions, physicians should routinely ask about them (Table 128-1).

HIV testing should be conducted as part of a diagnostic workup in any patient with unexplained anemia, peripheral neuropathy, oral candidiasis, widespread herpes zoster, recurrent bacterial pneumonia, or any of the more traditional AIDS-associated conditions (Pneumocystis carnii pneumonia, Kaposi’s sarcoma, atypical mycobacterium, or tuberculosis). Finally, any patient for whom more common causes of debilitating fatigue or weight loss have been eliminated should be tested for HIV.

The blood test is simple, accurate (sensitivity and specificity >99.9%), and widely available. It involves two steps. The first step is a screening enzyme immunoabsorbent assay for HIV antibody. If this test is positive, a western blot is used to confirm the diagnosis. If the first test is negative, the patient is considered uninfected. Even in low-risk populations such as blood donors, the false-positive rate of these combined tests is low (<0.001%). When an individual tests positive, it is important to inform them of these results with as much care as you would any other life-changing diagnoses like that of cancer or diabetes. It is particularly important that you facilitate their integration into a clinical practice with substantial experience in the treatment of HIV infection. Comanagement may be needed if the patient has a substantial burden of age-related comorbid conditions or frailty.

Survival without treatment from the time of first AIDS-associated diagnosis is on the order of 1 to 2 years (median). Survival with current multiclass, combination antiretroviral treatment has not been fully characterized, but estimates suggest that current treatments confer between 10 and 25 additional years of survival. Of note, prognosis is poorer among those who present late for care or fail to adhere to their treatment regimen.