Doctors have noticed for some time that their HIV-positive patients have had lower bone density. They saw their HIV patients' bones were more brittle than those who don't have HIV. And, as Rose Hoban reports, brittle bones tend to break more easily.
Harvard professor Steven Grinspoon wanted to see if HIV-positive patients actually were more likely to have broken bones. He used a large database at the Massachusetts General Hospital in Boston that has more than a decade's worth of data. They characterized patients based on whether they had HIV or not.
"There were over 8000 HIV-infected patients, and there were over 2 million non-HIV-infected individual patients," says Grinspoon.
With so much information, Grinspoon says it was easy to see whether there was a difference in the number of patients who broke their bones. He found there was a 60% increase in the prevalence of fractures in many parts of the body – hips, spines and arms. Grinspoon found this to be the case for most patients: men and women, minority and non-minority.
As people get older, they're more likely to break a bone. But in Grinspoon's study, HIV patients were even more likely than usual to suffer a fracture or break as they aged.
But Grinspoon says the study doesn't give any indication as to why HIV positive patients are more likely to break bones. "Is it the HIV virus?" he asks. "Is it the medicines that are associated with HIV, that patients take for that? Is it some other mechanism? We simply don't know."
Most of the HIV-positive patients in this study were taking antiretroviral drugs and were therefore living longer with the virus. But in many parts of the world, anti-retroviral therapy is unavailable. Grinspoon says even if patients in poorer countries don't live as long, they might actually be at as great a risk of fracturing a bone as someone in his study – if not more.
"Weight and nutrition is a huge factor for bone loss in any set of patients, HIV… [or] not," he says. "And generally patients are better nourished here as opposed to developing countries where … patients can be very, very thin, and wasted. So there may be even more of a problem with bone density and fractures in those populations." Again, Grinspoon says there are no clear answers.
Grinspoon says he'll be trying to answer some of these questions in his future research. His paper is published in The Journal of Clinical Endocrinology and Metabolism.