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ICAAC 2012: Bone Loss Is Common in French HIV Cohort, Linked to Older Age and Lower Weight

As many as half of people with HIV may have some degree of bone loss -- and up to 20% may experience fractures -- but no other significant risk factors could be determined other than older age and low body mass index, researchers reported at the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2012) this month in San Francisco.

A number of observational studies have found that people with HIV have higher rates of osteopenia (decreased bone mineral density) and osteoporosis (more severe bone loss) compared with the general population.

The cause is not well understood, but HIV infection itself, resulting inflammation or metabolic changes, and side effects of antiretroviral drugs may all play a role. HIV protease inhibitors and the NRTI tenofovir (Viread, also in the Atripla, Complera, and Stribild coformulations) have been associated with bone toxicity.

Lucie Lemeunier from Tourcoing Hospital and colleagues conducted a retrospective observational study of the frequency of and risk factors for osteopenia and osteoporosis among people with long-term HIV infection.

The analysis included data from 199 HIV positive patients (148 men and 51 women), with a median age of 47 years, seen at a single center in France between March 2005 and July 2011. During follow-up participants underwent DEXA (dual X-ray absorptiometry) assessments of the femoral neck (ball of the hip), total hip, and lumbar (lower) spine.

Results

• 70 men (47.3 %) and 20 women (39.2 %) had evidence of osteopenia.
• 32 men (21.6 %) and 8 women (15.7 %) had more severe osteoporosis.
• Osteoporosis was predominantly seen at the femoral neck in both men and women.
• Overall, the only factors that differed significantly between people with and without osteoporosis were age and body mass index (BMI); patients with osteoporosis were older and had lower body weight on average.
• No differences in osteoporosis rates were seen in relation to any of other analyzed known or potential risk factors, including CD4 T-cell count, HIV viral load, use of antiretroviral therapy (ART), duration of exposure to HIV treatment overall and specific antiretroviral drug classes, lipodystrophy, hepatitis C coinfection, family or personal history of fractures, smoking, alcohol use, use of corticosteroids or other hormone therapy, and vitamin D status.
• A simple regression analysis showed that femoral neck bone mineral density was significantly associated with age, BMI, and duration of NRTI treatment without tenofovir.
• BMI was the only parameter significantly associated with both total hip and lumbar spine bone density.
• A multiple regression analysis showed that:

o   Age and BMI together explained 20.8% of the variability in bone mineral density of the femoral neck;

o   BMI alone explained 10.1% of variability in density of the total hip;

o   BMI plus duration of tenofovir use explained 7.1% variability in density of the spine.

• 337 study participants (18.6%) had a history of fractures, including 3 with vertebra breaks. 
• After adjusting for age and BMI, lower CD4 count was the only factor significantly associated with fracture history.
• 5 people were found to have secondary causes of osteoporosis, including 1 each with Fanconi syndrome (a type of kidney dysfunction) linked to tenofovir, hyperparathyroidism, hemochromatosis (iron overload), and hypogonadism (low sex hormone levels).
• Low vitamin D was common, with 65% having some degree of insufficiency and another 24% having a deficiency. 

The researchers concluded that, "The results of the present study suggest a high prevalence of osteopenia and osteoporosis in HIV-infected patients in accordance with those of previous studies" -- 23% to 65% for osteopenia and 3% to 22% for osteoporosis.
 
"Only age and BMI were significantly associated with both osteopenia and osteoporosis," they continued, but "[w]e did not find, as previously reported, any association between tenofovir treatment and low bone mineral density in our population." CD4 count, they added, "might be related to fracture risk assessment, probably due to other confounding factors."

9/28/12

Reference

L Lemeunier, NViget, E Biver, et al. An Observational Study Of Bone Status in HIV-infected Patients. 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2012). San Francisco. September 9-12, 2012. Abstract H-231.