HIV infection alone does not increase risk of diabetes

HIV infection itself does not increase the risk of diabetes, US investigators report in the June 19^th edition of AIDS. Indeed, the results of the research showed that, at the start of the study, people with HIV had a lower risk of diabetes than HIV-negative individuals.

However, this was because of the low body mass index (BMI) of untreated HIV-positive individuals, and an improving immune status, treatment with antiretroviral drugs, and hepatitis C virus were all shown to increase diabetes risk in people with HIV.

“We believe that the net risk of diabetes mellitus is determined by a complex interplay of individual factors, with the traditional risk factors dominating the profile leading to an overall lower risk in HIV-infected persons,” comment the investigators.

The association between HIV infection and diabetes mellitus is poorly understood. This is partly because people with HIV have a different prevalence of risk factors for the condition than HIV-negative individuals.

There is however general agreement that traditional risk factors for diabetes, such as increasing age, obesity, and race, are responsible for most cases of the condition diagnosed in people with HIV. What is less clear is the role of risk factors such as the use of antiretroviral drugs and co-infection with hepatitis C virus.

Earlier research has yielded conflicting results about the risk factors for diabetes in people with HIV. Therefore investigators from the US Veterans Aging Cohort Study designed a case-controlled study to determine the association between HIV and diabetes and its risk factors.

A total of 3227 HIV-positive patients and 3240 HIV-negative controls were included in the research.

The people with HIV were younger (49 years vs 51 years, p < 0.001), and more likely to be men (98% vs 92, p < 0.001), black (67% vs 62%, p < 0.001), and infected with hepatitis C virus (31% vs. 15%, p < 0.001) than the controls.

The baseline prevalence of diabetes was significantly lower (p < 0.001) amongst people with HIV (15%) than those who were HIV-negative (21%).

However, the investigators found that this was entirely explained by the HIV-positive patients having a lower BMI.

Multivariate analysis that controlled for possible confounding factors confirmed that overall people with HIV had a lower risk of diabetes (OR = 0.84, 95% CI: 0.72 to 0.97).

Traditional risk factors for diabetes (increasing age, male sex, black race and increasing BMI) were, however, more strongly associated with the development of diabetes in people with HIV than HIV-negative individuals.

Furthermore, the investigators’ analysis showed that co-infection with hepatitis C virus significantly increased the risk of diabetes in people with HIV but not those who were HIV-negative.

Treatment with combination antiretroviral therapy also increased the risk of diabetes (OR = 1.11; 95% CI: 1.05 to 1.17). Treatment with drugs from the nucleoside reverse transcriptase inhibitor (NRTI) and non-nucleoside reverse transcriptase inhibitor (NNRTI) classes were also associated with an increased risk of diabetes, as was the cumulative length of exposure to antiretroviral therapy.

The researchers also found a weak association between having a CD4 cell count above 500 cells/mm³ and a higher risk of diabetes, compared to people with lower CD4 cell counts. They hypothesise that could be because of the weight gain that accompanies improving health status after initiating HIV therapy.

Intriguingly, neither drug nor alcohol use were associated with a higher risk of diabetes, a finding that the investigators struggled to offer an explanation for.

“In conclusion”, write the investigators, “we found that HIV itself is not associated with a higher risk of diabetes mellitus. In fact, after adjusting for traditional risk factors, HIV is actually associated with a lower risk. A return to a more healthy state with increasing BMI and CD4 lymphocyte counts was associated with a higher risk of diabetes. However, the magnitude of association with the traditional risk factors varies between HIV infected and uninfected persons.”