Care of the aging HIV patient
ABSTRACTThanks to antiretroviral therapy, human immunodeficiency virus (HIV) infection has become a controllable chronic disease, and many infected patients are now living into their 60s and beyond. In addition, many patients with newly diagnosed HIV infection are over age 50. The subsequent rising prevalence of HIV infection in older adults presents several challenges for primary care clinicians. This article promotes increased HIV screening in older adults and highlights the need to recognize polypharmacy and the various comorbidities inherent in the aging HIV population.
KEY POINTS
- Today, nearly 20% of newly diagnosed HIV-infected people and more than 50% of all HIV-infected people in the United States are over age 50.
- The diagnosis and treatment of HIV tends to be delayed in elderly patients, with deleterious effects.
- Antiretroviral drugs have a number of interactions with drugs commonly used in elderly patients.
- Several diseases are more common in HIV-positive patients, including cardiovascular disease, diabetes mellitus, osteoporosis, dementia, and various malignant diseases. These merit aggressive screening and preventive measures.
SO MANY DRUGS, SO MANY INTERACTIONS
Since HIV patients are now living longer thanks to antiretroviral therapy, they are now experiencing more disease- and treatment-related problems. This has led to an increased likelihood of polypharmacy, defined here as the use of six or more medications.
In general, polypharmacy in the elderly is associated with adverse drug events, drug interactions, inappropriate medication use, delirium, falls, fractures, and poor medication adherence.22,23 But it becomes even more of a problem in HIV-infected elderly patients, as various drug interactions can alter the effectiveness of the antiretroviral regimen and can result in drug toxicity.
The most common classes of medications used in the elderly are antihypertensives, lipid-lowering agents, antiplatelet medications, antidepressants, anxiolytics, sedatives, and analgesics, and many of these have notable interactions with current antiretroviral regimens.24,25 Most medications, including antiretrovirals, are cleared by the liver or kidneys, and the function of these organs often decreases with age, resulting in impaired elimination and in drug accumulation.
Information on drug interactions is readily available from the US Department of Health and Human Services,26 drug interaction databases,27,28 and drug interaction software. The combination of antiretroviral therapy and preexisting polypharmacy significantly increases the risk of serious interactions, which can lead to drug toxicity, poorer adherence with antiretroviral therapy, loss of efficacy of the coadministered medication, or resurgence of HIV infection due to drug-drug interactions affecting the metabolism and ultimate efficacy of the antiretroviral therapy. An increased awareness of common drug-drug interactions can prevent coadministration of potentially harmful medications in elderly HIV patients.
Important interactions between antiretroviral drugs and other drug classes are summarized in Table 1.25–28 Most notably:
- Simvastatin and lovastatin are contraindicated with any protease inhibitor.
- Proton pump inhibitors are not recommended for patients taking ritonavir-boosted atazanavir. If a proton pump inhibitor is necessary, the daily dose should not exceed 20 mg of omeprazole or its equivalent in patients who have never taken a protease inhibitor, and it should be taken 12 hours before boosted atazanavir.26
- Corticosteroids, whether systemic, inhaled, or intranasal (eg, fluticasone, budesonide), should be avoided in combination with any protease inhibitor, as they can cause iatrogenic Cushing syndrome and also pose the risk of adrenal crisis during acute illness.27
Take-home points
- In cases of preexisting polypharmacy, antiretroviral therapy can lead to significant drug toxicity, poor adherence to medications, and resurgence of HIV infection.
- Increased provider awareness of common drug-drug interactions can prevent the prescribing of potentially harmful drug combinations to HIV-infected elderly patients.
COMORBIDITIES
In recent years, more than half of the deaths in HIV patients on antiretroviral therapy have been from noninfectious comorbidities such as cardiovascular disease, bone disease, and renal failure, which often coexist and are associated with advanced age.29 In fact, both older age and each additional year of antiretroviral therapy are independent predictors of polypathology (simultaneous occurrence of two or more defined diseases).30 The Antiretroviral Therapy Cohort Collaboration found that age greater than 50 was strongly associated with increasing rates of non–AIDS-related malignancy and cardiovascular disease.31
CARDIOVASCULAR DISEASE
With the increasing life expectancy of HIV-infected adults on antiretroviral therapy, cardiovascular disease has become an important concern. HIV-infected adults appear to have a significantly greater risk of myocardial infarction and coronary artery disease than age-matched HIV-negative individuals.32 Strikingly, being older than 50 itself increases the risk of hospitalization for cardiovascular disease fivefold (incidence rate ratio 5.01, 95% confidence interval 3.41–7.38).33 In addition, HIV infection is associated with a risk of acute myocardial infarction 50% higher than that explained by recognized risk factors.34
This high prevalence of coronary artery disease is likely from a combination of factors, including increasing age and the chronic inflammation and immune activation associated with HIV infection.35 An association between untreated HIV disease and markers of risk for cardiovascular disease has been identified.36,37
In addition, antiretroviral therapy is associated with dyslipidemia, which is most pronounced with protease inhibitor regimens. Whether specific lipid changes associated with individual antiretroviral drugs affect cardiovascular risk remains uncertain. In the Data Collection on Adverse Events of Anti-HIV Drugs studies,38 only cumulative exposure to indinavir, lopinavir-ritonavir, and didanosine was associated with an increased risk of myocardial infarction.38
Traditional risk factors such as obesity, tobacco use, and genetic predisposition also apply to HIV-infected people.39 In fact, the prevalence of traditional risk factors such as smoking and dyslipidemia is generally higher in HIV-infected people than in the general population, although this situation may be improving.40
Science needs to elucidate the relationship between traditional and nontraditional risk factors for cardiovascular disease in older HIV-infected adults. In the meantime, older patients with HIV require aggressive management of modifiable risk factors.
Tools for assessing cardiovascular risk include the Framingham risk score41 and the Data Collection on Adverse Events of Anti-HIV Drugs 5-year risk calculator.42 The European AIDS Clinical Society guidelines recommend considering changing the antiretroviral regimen if the patient’s 10-year risk of cardiovascular disease is more than 20%.43 Recommended strategies for reducing cardiovascular risk in elderly patients with HIV infection include counseling about smoking cessation and weight loss at every clinic visit and optimally controlling dyslipidemia and hypertension using nationally accepted standardized guidelines.44
Take-home points
- HIV infection is associated with a 50% higher risk of acute myocardial infarction beyond that explained by traditional risk factors.
- Chronic inflammation, immune activation, and dyslipidemia associated with antiretroviral therapy all contribute to cardiovascular disease in HIV-infected patients.
- HIV-infected elderly patients require aggressive management of modifiable risk factors for cardiovascular disease.
