PHILADELPHIA, PA—Dually treated HIV/HBV co-infected patients had a higher risk of hip fracture than HBV mono-infected, antiretroviral therapy (ART)-treated HIV-mono-infected, and HIV/HBV uninfected patients, a study reported at IDWeek 2014.

“HIV and hepatitis B virus (HBV) infection are each associated with reduced bone mineral density, but it is unclear whether HIV/HBV co-infection is associated with an increased risk of fracture,” reported Dana D. Byrne, MD, MSCE, from Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. To address this, Dr. Byrne and colleagues conducted a population-based cohort study comparing the incidence of hip fractures in dually-treated HIV/HBV co-infected patients, to treated HBV mono-infected, antiretroviral therapy (ART)-treated HIV mono-infected, and uninfected patients.

A total of 4,156 dually-treated HIV/HBV co-infected patients were matched on propensity score to 2,053 HBV mono-infected patients receiving nucleos(t)ide analogue or interferon alfa therapy, 96,253 HIV mono-infected receiving ART, and 746,794 randomly sampled uninfected persons. Patients were from U.S. Medicaid populations in California, Florida, New York, Ohio, and Pennsylvania, between 1999 and 2007. Cumulative incidences and hazard ratios (HR) at 5 years were estimated using weighted survival models, accounting for competing risks.

At 5 years, the cumulative incidence of hip fracture was higher among dually-treated HIV/HBV-co-infected patients compared to ART-treated HIV mono-infected (1.7% vs. 1.24%; adjusted HR 1.37; 95% CI 1.03–1.83) and uninfected persons (1.48% vs. 0.83%; adjusted HR 1.83; 95% CI 1.33–2.51). Cumulative incidence was also higher among dually-treated HIV/HBV co-infected patients than among treated HBV mono-infected patients (0.70% vs. 0.27%), but not statistically significant in competing risk analysis (adjusted HR 2.62; 95% CI, 0.92–7.51). 

The dually-treated HIV/HBV cohort was associated with 4.3 additional hip fractures per 1,000 compared to treated HBV mono-infected, 4.6 additional fractures compared to ART-treated HIV mono-infected persons, and 6.6 additional hip fractures per 1,000 compared to uninfected persons,” reported Dr. Byrne.

“Among Medicaid enrollees, the risk of hip fracture was significantly higher among dually treated HIV/HBV co-infected patients than ART-treated HIV-mono-infected and uninfected persons,” concluded Dr. Byrne, and suggested that “future studies should examine mechanisms for bone disease as well as interventions and therapies to prevent fractures among co-infected patients.”