Written by William G. Powderly, MD, Larry J. Shapiro director of Institute for Public Health and professor in the Department of Medicine in the School of Medicine
One of the most positive features of the current era of HIV, particularly in the Western world, is the fact that patients are aging successfully. In the 1980s, when the disease was first recognized, the average survival after someone was given a diagnosis of AIDS was approximately two years; indeed, on average, the interval between acquisition of HIV infection and the development of AIDS was about ten years.
In contrast, we are now looking at situation where survival is very significantly better. Indeed it is now possible for physicians to say to a young person in whom HIV has been recently diagnosed that if they start therapy and take it as prescribed, they can expect a normal lifespan. What this reflects is the fact that effective treatment for HIV (antiretroviral therapy, ART) has become easier and less toxic since it first became available in the mid-1990s.
As a result of these medical advances, the population of patients living with HIV is graying. In the western world (including the US) nearly one third of all HIV-infected patients are over 50 years of age. So, whereas previously the challenge for HIV-infected patients was to survive initial AIDS illnesses and prevent AIDS-related infections and cancers, they now face the same challenges as the rest of the population as it gets older. Increasingly the major causes of sickness and death in health in older HIV-positive patients are the same as other patient groups – heart disease, cancer, kidney disease and age-associated neurological decline.
The first thing is to realize that we still need more research – especially to determine if there is a need for a different approach to diagnose and prevent these chronic illness in HIV-infected patients.
Interestingly, there are quite a number of epidemiologic studies that suggest that these illnesses may be more common among HIV-infected patients and, they may occur earlier in life than one might see in uninfected patients. This has given rise in some circles to the concept that in some way HIV may accelerate aging. Personally, I do not subscribe to the view that the biologic process of aging is in any way accelerated by HIV infection. For one, it is difficult to generate a unifying hypothesis that explains all the clinical data. Moreover, many of the studies cited to justify something very different for HIV are poorly controlled, especially for factors that might also predispose to chronic illness. Nevertheless, from a public health perspective, understanding the factors that might lead to increased rates of chronic illness are important, in order to develop strategies that might prevent them.
So why might HIV-infected patients get more chronic diseases of aging? First of all, we know that many of these diseases – cardiovascular disease and cancer in particular – are diseases of lifestyle. Lifestyle factors that influence chronic disease are more common in HIV infected patients. In most studies, they have twice the rate of cigarette smoking, have more mental illness, and are more likely to have used drugs at some point in their life. Certain viral infections, notably human papilloma virus (HPV), are more common in HIV-infected patients, and are increasingly implicated in a number of cancers. Drugs used to treat HIV may contribute high blood lipids, diabetes, osteoporosis, and kidney diseases.
There may, too, be a contribution from HIV infection itself. One of the hallmarks of chronic HIV infection is persistent chronic inflammation. Indeed there is some evidence that even with effective control of the virus by ART (where there is no evidence of virus in the blood) there may be persistent inflammation. Increasingly we are realizing that inflammation may be an important contributor to chronic diseases – implicated especially in the development of atherosclerosis (which can lead to heart disease and stroke) and kidney disease.
What does this mean for the person living with HIV infection? The first thing is to realize that we still need more research – especially to determine if there is a need for a different approach to diagnose and prevent these chronic illness in HIV-infected patients. Equally, we need to ensure that we pay the same (if not greater) attention to the risk of chronic illness in these older HIV-positive patients as we do in the general population. Patients need regular assessment of their cardiovascular risk, with testing for cholesterol and diabetes. They should have cancer screening as is recommended for the general population – colonoscopy, mammography, etc. – as well as regular screening for HPV-related cancers of the cervix and anus. Above all, they should be encouraged, counseled, and supported in their efforts to stop smoking, as this is singly the most important preventive effort we can offer.