(AIDSmeds.com) - (AIDSmeds.com)—A literature review involving several studies suggests that the prevalence of osteoporosis in HIV-positive people is more than three times greater compared with HIV-negative individuals. The review, conducted by Todd Brown, MD, of Johns Hopkins University, and Roula Qaqish, PharmD, of Abbott Laboratories, indicates that HIV-positive patients treated with antiretrovirals were most likely to experience reduced bone strength compared to HIV-positive patients not on treatment.
Bone consists of two important components: collagen and mineral. Bone is mostly made up of collagen. Collagen provides a soft framework and gives bones necessary flexibility. The mineral component includes calcium and phosphate and hardens the collagen framework.
Osteoporosis is diagnosed when a DEXA scan suggests that a person's bone mineral has been depleted – referred to as low bone mineral density (BMD) in the medical literature – and likely to increase the risk of fracture. While the greatest risk of fracture involves the wrist, hip, or spine, virtually any bone in the body is more likely to break in someone who has osteoporosis.
Osteopenia is a more mild form of bone loss. While it is not associated with an increased risk of a fracture, it is an indicator of lower-than-normal BMD. Over time, osteopenia can progress to osteoporosis.
Among HIV-positive people, reduced BMD has been reported in a number of studies and by numerous "real world" healthcare providers. However, because of the small size of the studies – and inconsistencies between the anecdotal reports – researchers have not been able to accurately determine if decreased BMD is more common in HIV-positive people compared to HIV-negative people.
What's more, researchers initially suggested that osteopenia and osteoporosis were side effects of HIV treatment, notably protease inhibitor (PI) therapy. However, other factors – such as the effects of chronic immune activation, age, body mass index (BMI), smoking, and alcohol use – appear to play an important role in the development of osteopenia and osteoporosis. Plus, some studies have failed to show a connection between HIV treatment use and low BMD in HIV-positive people.
Based on these outstanding questions, Drs. Brown and Qaqish performed a detailed literature review involving 20 BMD studies conducted over the past five years. These studies allowed for comparisons between HIV-negative and HIV-positive people, as well as HIV-positive people receiving or not receiving antiretroviral treatment.
Eleven studies were used to compare HIV-negative and HIV-positive patients. Of the 884 HIV-positive patients in the 11 studies, 593 (67%) had reduced BMD, or whom 135 (15%) had osteoporosis. Compared with the 654 HIV-negative controls, HIV-infected patients had a 6.4-fold increased risk of reduced BMD and a 3.7-fold increased risk of osteoporosis.
Ten studies were used to compare rates of reduced BMD in HIV-positive patients receiving antiretroviral treatment and those who had not yet been on an HIV drug regimen. Among the 824 antiretroviral-treated patients in the studies, there was a higher prevalence of reduced BMD compared with the HIV-positive patients not on therapy. In addition, averaging the results of seven studies that included appropriate data, the risk of osteoporosis was increased 2.4 times in the antiretroviral-treatment patients compared to the antiretroviral-naïve patients.
Finally, 14 studies were used to compare the prevalence of reduced BMD in HIV-positive patients receiving a PI with those not receiving a PI. In short, there was a higher prevalence of reduced BMD among the 791 PI-treated patients compared with the PI-untreated patients. The risk of osteoporosis was 1.6 times greater with the use of a PI, compared to those not treated with a PI.
In conclusion, Drs. Brown and Qaqish reported the average prevalence of osteoporosis to be 15% in the HIV-positive patients, which is more than three times higher than that observed in HIV-uninfected people. Moreover, antiretroviral-experienced and PI-treated HIV-positive patients appeared to have a higher risk of reduced BMD and osteoporosis compared with their HIV-negative, antiretroviral-naïve, and PI-inexperienced counterparts.
However, Dr. Brown and Qaqish cautioned that the influence of other potentially important factors on these risks – such as age, duration and severity of HIV infection, and other risk factors like smoking and alcohol use – could not be determined. Additional studies, they write, are necessary to look even more closely at all of these possible links.
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