HIV increases fracture risk, say Danes

HIV infection increases the risk of fractures, Danish investigators report in the online edition of the Journal of Acquired Immune Deficiency Syndromes. The case controlled study used data collected by national registries in 2000.

“We report a significantly increased prevalence of HIV infection of almost 3-fold among fracture cases, compared to gender and age-matched controls from the Danish health registries,” write the investigators. “This is, in our data, independent from potential confounders, including fracture history, alcoholism, use of potentially involved medications (sedatives, opioids, antidepressants, anticonvulsants, antipsychotics, and corticosteroids), and annual income.”

The investigators believe their findings stress the importance of evaluating fracture risk as part of routine HIV care.

There is a well-established link between infection with HIV and impaired bone metabolism. The exact reasons for this are uncertain, but possible causes include lifestyle factors, the inflammatory effects of HIV infection and the side-effects of some antiretroviral drugs and other medicines.

It is equally unclear if these bone metabolism problems increase the risk of fractures, an important question given the ageing of the HIV-infected population.

To help clarify this pressing question, investigators in Denmark designed a retrospective case-controlled study using data collected from national registries. The study population included 124,655 fracture patients who were matched with 373,962 non-fracture patients of the same age and sex. The authors calculated the association between infection with HIV and any fracture and also with  fragility fractures – fractures of hip, forearm, spine or any other fracture not related to accidents.

In calculating the association between HIV and fracture, the investigators took into account other factors known to have an association with fracture risk – previous fracture, heavy alcohol use, low annual income, treatment with corticosteroids and the use of medications affecting motor function and co-ordination.

Results were stratified according to gender and age, and the investigators also explored the association between the duration of HIV infection and fracture risk.

The cases and controls had a mean age of 43 years and 52% were women.

HIV prevalence among cases was 0.04% compared to 0.01% among the controls, a significant difference. HIV infection was therefore associated with an almost three-fold increase in the risk of fracture (OR = 2.98; 95% CI, 1.99-4.18).

The prevalence of HIV infection was also significantly higher among people experiencing hip fracture (0.03 vs < 0.01%; OR = 8.99; 95% CI, 1.39-58.0), fracture of the forearm (0.03 vs 0.01%; OR = 3.50; 95% CI, 1.26-9.72) and fracture of the spine (0.09 vs < 0.01%; OR = 9.0; 95% CI, 1.39-58.1).

After taking account of all other risk factors, infection with HIV continued to be associated with the overall risk of fractures (OR = 1.76; 95% CI, 1.14-2.71), the association between specific types of fracture ceased to be significant.

HIV-positive men had an almost three-fold increase in their risk of fractures compared to HIV-negative men (OR = 2.73; 95% CI, 1.78-4.19) and HIV-positive women had an almost four-fold increase in their risk (OR = 3.75; 95% CI, 1.48-9.50).

Comparison by age also showed that infection with HIV was associated with an increased risk of fracture for younger (OR = 2.76; 95% CI, 1.57-4.86) and middle-aged (OR = 3.12; 95% CI, 1.80-5.41) participants. But HIV infection was not associated with an increased risk of fracture for people aged 60 and older.

The excess risk associated with HIV increased with the duration of infection. The risk increased especially rapidly during the first two to three years and then increased more slowly.

“HIV-infected adults are at an highly increased risk of hip and other bone fractures, compared to the general population,” conclude the authors. “HIV-infected patients should be assessed for fracture risk as part of their routine care.”