Previous research has shown that people with HIV or hepatitis C virus (HCV), and especially those with both infections, are at greater risk for bone loss. Hepatitis B virus (HBV) can also negatively affect bone health, but the effects of HIV/HBV coinfection have not been well studied. While the mechanisms are not fully understood, direct viral effects, resulting inflammation, and drug toxicities may all play a role in bone loss. People with these infections also commonly have other risk factors including smoking, alcohol use, and low body weight.

The nucleotide analog tenofovir (Viread, also in Truvada and other coformulations) -- which is known to cause a small amount of bone loss soon after starting therapy -- is active against both HIV and HBV, and guidelines recommend that HIV/HBV coinfected people should include it in their antiretroviral therapy (ART) regimen.

Dana Byrne and Vincent Lo Re from the University of Pennsylvania and colleagues studied whether dually-treated HIV/HBV coinfected people have a higher incidence of hip fractures compared to HIV-monoinfected patients on ART, HBV-monoinfected patients treated with nucleoside/nucleotide analogs, and uninfected people with neither virus.

This population-based retrospective cohort study included 4156 HIV/HBV coinfected people, 96,253 people with HIV alone, and 2053 people with HBV alone, along with 746,794 randomly sampled uninfected people in the Medicaid populations of California, Florida, New York, Ohio, and Pennsylvania during 1999-2007.

Results

• Over 5 years, dually-treated HIV/HBV coinfected patients had a significantly higher likelihood of hip fractures than ART-treated HIV-monoinfected people, with cumulative incidence rates of 1.70% vs 1.24%, respectively (adjusted hazard ratio 1.37), and 4.6 additional fractures per 1000 coinfected patients.
• HIV/HBV coinfected patients had a higher likelihood of hip fractures than people with HBV alone, though this did not reach statistical significance; cumulative incidence rates were 0.70% vs 0.27%, respectively, with 4.3 additional fractures per 1000 coinfected patients.
• Finally, HIV/HBV coinfected patients also had a significantly higher likelihood of fractures than uninfected individuals, with cumulative incidence rates of 1.48% vs 0.83%, respectively (adjusted hazard ratio 1.83), and 6.6 additional fractures per 1000 coinfected patients.

"Among Medicaid enrollees, the risk of hip fracture was significantly higher among dually-treated HIV/HBV patients than ART-treated HIV-monoinfected and uninfected persons," the researchers concluded.

"Future studies should examine mechanisms for bone disease as well as interventions and therapies to prevent fractures among coinfected patients," they recommended.

10/22/14

Reference

V Lo Re, D Byrne, C Newcomb. Increased Risk of Hip Fracture Associated with Dually-Treated HIV/Hepatitis B Virus Coinfection. IDWeek 2014. Philadelphia, October 8-12, 2014. Abstract 1603.