Coverage of CROI 2008 (Conference on Retroviruses and Opportunistic Infections)

February 4–6, 2008, Boston, MA

 

Bone loss remains an issue for
people taking HIV drugs

February 6, 2008

As people with HIV take HIV drugs over time, a growing list of conditions often become an issue. These include bone problems and liver or heart disease, among many others. One area of research continues to examine the relationship between HIV and bone problems, like bone density loss (osteopenia), bone loss (osteoporosis), and bone death (osteonecrosis). Several studies about bone conditions and HIV disease reported findings at CROI 2008.

Bone loss in first line therapy
One study looked at the cause of the loss of bone mineral density (BMD) in people taking HIV drugs for the first time, also called first line therapy. The study enrolled 155 individuals who had never taken HIV drugs. Volunteers took either Kaletra (lopinavir + ritonavir) or Sustiva (efavirenz) with Combivir (Retrovir/zidovudine + Epivir/lamivudine) for 24–48 weeks. After 48 weeks, they were switched to Kaletra monotherapy through to 96 weeks. Every 24 weeks, the volunteers had DEXA scans done that measure bone density. Other factors known to affect bone loss were also considered such as smoking, drinking, weight, demographics and body composition.

Similar decreases in BMD were seen in both groups taking the two different regimens. As well, the decreased BMD continued at about the same rate through the later period of monotherapy. These data suggest that the loss of BMD after starting HIV therapy occurs independently of the HIV drugs used. This points to others factors that may be causing this loss, such as changes in immune function or HIV’s activity in the body. The study also showed that non-black volunteers and those with lower nadir (lowest ever) CD4 counts may be at a higher risk of more pronounced BMD loss.

Bone loss in three different regimens
A second study looked at BMD loss in people taking HIV drugs for the first time. This sub-study of the Hippocampe-ANRS 121 study followed 71 people over 48 weeks and examined the BMD in the hip and spine. The volunteers were 77% male (average age 40), 69% Caucasian and 58% smokers. One of three regimens was given: one NNRTI + one protease inhibitor (PI), one PI + 2 NRTIs, or one NNRTI + 2 NRTIs.

After 48 weeks, there was marked loss of BMD in both sites for all three groups. For the regimens with a PI, there was a greater loss in the spine. DEXA scans at the start of the study and before taking therapy revealed that about a third of the volunteers already showed some osteopenia, with a couple of them having osteoporosis. This suggests that HIV contributes to the loss of BMD in people taking therapy.
                                                                                                            
Bone loss and HAART
Another study also looked at the role of HIV therapy and loss of BMD. This study followed 299 patients over two and a half years. Of the volunteers, 79% were Caucasian, 89% male, and the average age was 48 years.

The results showed that 2 out of 3 had abnormal DEXA scans: 54% had osteopenia and 13% osteoporosis. Several factors contributed to low BMD for all volunteers, including older age, low body mass index (BMI), ethnicity and low CD4 counts. For men, low physical activity and drinking alcohol also contributed to low BMD. Interestingly, the data in general did not show a relation of taking therapy to BMD loss, except for the HIV drug Viread (tenofovir). Unlike the other study, PIs were not shown to contribute to bone loss.

Bone loss and viral hepatitis infection
This study looked at the role that viral hepatitis may have in BMD loss over time. The two-year study enrolled volunteers with and without viral hepatitis and took BMD measurements of the whole body, spine and thigh. Other readings were taken including bone mineral content and fat and lean body mass.

The results confirm other findings of a high rate of bone mineral and metabolism disorders in people living with HIV. The results also showed that bone metabolism rapidly changed over the two years of the study. However, viral hepatitis did not show having a role in the loss of BMD.

Commentary
These studies stress the need for more research on the underlying reasons for bone mineral loss and other bone disorders in people living with HIV. They also underscore the importance of patients and doctors monitoring bone issues while on HIV therapy, even at the start of therapy. Getting a baseline test before starting therapy and then regular tests afterwards can help identify the start of bone loss.

As well, addressing other health issues that can contribute to decreased BMD may help prevent some of the loss over time. These include low BMI, lack of physical activity, older age, drinking alcohol and low CD4 count. Talking about bone loss with your health provider can go a long way in helping you stay as healthy as possible.