Obesity Slows Immune Recovery in HIV

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Preliminary data presented at the annual meeting of the Infectious Diseases Society of America found that the immune systems of HIV patients who are obese do not respond to antiretroviral therapy as well as do those of people of normal weight.

According to Nancy Crum-Cianflone, MD of the University of Health Sciences in San Diego, HIV patients who are obese at diagnosis regain fewer CD4-positive T cells after they start therapy than do people within an ideal weight.

Crum-Cianflone and colleagues reviewed data from the U.S. Military Natural History Study, which includes 1,119 patients diagnosed with HIV between the 1986 and 2008. Obesity was determined using the standard definition of BMI greater than 30. Normal weight was defined as BMI between 18.5 and 24.9.

Patients were treated with highly active antiretroviral therapy, also called HAART. The use of HAART results in immune system recovery, measured by an increase in the number of CD4 cells. Patients treated with HAART who were of normal weight regained 103 CD4 cells on average. But the patients who were obese only regained 69 cells over time.

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The study finding is different from previous research, which found that patients who were obese did better than those of normal or below-normal weight. Prior research had shown that obese patients given HAART lost CD4 cells more slowly than those at either normal weight or were underweight.

The study also reflects a current concern of the increased number of HIV patients who are obese. Current research indicates that nearly two-thirds of the HIV population may be overweight or obese, mirroring that of the overall US population.

Crum-Cianflone said that it is not clear why obesity should have such an effect. One theory is that standard drug dosing may not be enough for obese patients. Obesity alters the pharmacokinetics in many drugs, and can either result in therapeutic failure or increased toxicity, according to research by Jane Lee in Orthopaedics Today.

Obesity in itself has ill effects in the HIV population. The study participants who were obese had lower average CD4 cell counts at diagnosis than those of normal weight. In addition, HAART has been associated with significant increases in total cholesterol levels, according to research in the Journal of Acquired Immune Deficiency Syndromes (JAIDS). Obesity can compound this, leading to an increased risk for cardiovascular disease.

More than one million people in the United States are living with HIV or AIDS, according to statistics from AVERT, an international AIDS charity.

Sources Include: Washington Post, Journal of the Association for Clinical Nutrition, Orthopaedics Today, and AVERT.

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