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HCV in HIV-Positives Raises Osteoporotic Fracture Risk Over 40%
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XVIII International AIDS Conference, July 18-23, 2010, Vienna
Mark Mascolini
Hepatitis C virus (HCV) coinfection independently inflated the risk of osteoporotic fracture in a 56,000-person US Veterans Affairs (VA) cohort [1]. Antiretroviral therapy more than halved the osteoporotic fracture risk in this analysis. The study is limited, though, because certain risk factors remain to be considered.
Osteopenia, osteoporosis, and resulting fractures have become more common in an aging HIV population. Because HCV has been associated with a higher fracture risk, VA researchers analyzed the impact of the hepatitis virus and other variables in a cohort of 56,660 HIV-infected VA beneficiaries, 98% of them men. The group's age averaged only 45 years, and follow-up averaged 5.4 years. The study included 17,281 people (30%) with HCV infection. Cohort members were cared for between 1988 and 2009. Almost two thirds of these people had taken antiretrovirals for at least 30 days, and treatment duration averaged 4.08 years.
Defining osteoporotic fractures as breaks of the wrist, vertebrae, or hip, the VA team identified 951 people with at least one osteoporotic fracture, usually wrist fractures, followed by hip fractures, then vertebral fractures. The fracture rate was 28% higher in HIV/HCV-coinfected people (3.25 per 1000 patient-years) than in those infected only with HIV (2.54 per 1000 patient-years). The group with osteoporotic fractures had significantly higher proportions of whites (57% white among those with fractures versus 45% among those without), smokers (56% versus 32%), people with diabetes (25% versus 15%), people with a body mass index below 20 kg/m(2) (49% versus 33%), and people with HCV infection (50.5% versus 31%) (P < 0.0001 for all comparisons). (from Jules: these are known risk factors in the general population for bone loss).
Among all HIV-positive patients, osteoporotic fracture rates per 1000 person-years remained fairly stable from 1988 through 2009. But fracture rates climbed steadily among HIV/HCV-coinfected people over this period. Multivariate statistical analysis determined that HCV infection independently raised the risk of osteoporotic fracture 43% (hazard ratio [HR] 1.43, 95% confidence interval [CI] 1.22 to 1.69, P < 0.0001). Antiretroviral use cut the osteoporotic fracture risk more than 50% (HR 0.44, 95% CI 0.35 to 0.56, P < 0.0001).
Every additional 10 years of age raised the osteoporotic fracture risk 50% (HR 1.50, 95% CI 1.38 to 1.63, P < 0.0001). White race boosted the fracture risk 75% (HR 1.75, 95% CI 1.49 to 2.40, P < 0.0001). Tobacco use raised the risk 48% (HR 1.48, 95% CI 1.26 to 1.75, P < 0.0001), and body mass index below 20 kg/m(2) upped the risk 40% (HR 1.40, 95% CI 1.13 to 1.73, P = 0.002). Chronic kidney disease and diabetes did not independently raise the risk of osteoporotic fracture.
This analysis did not weigh the potential impact of alcohol use and drug use, which are not uncommon among VA beneficiaries. A 10-year study of the HIV-positive French APROCO cohort, a more gender-balanced group than the VA cohort, found that HCV coinfection independently raised the risk of any grade 3 or 4 fracture 3.6 times, while excessive alcohol consumption independently upped the odds 2.9 times [2]. But the new fracture rate in APROCO did not differ substantially from the rate in people of similar age in the general European population.
In the VA study, osteoporotic fractures were independently associated with a 77% higher risk of death (HR 1.77, P < 0.001), as were HCV coinfection (HR 1.41, P < 0.0001), black race (HR 1.12, P = 0.0003), every 10 years of age (HR 1.60, P < 0.0001), and body mass index under 20 kg/m(2) (HR 2.27, P < 0.0001). Antiretroviral use independently lowered the risk of death 50% in this analysis (P < 0.0001), but diabetes did not affect death risk. An attendee observed that this analysis may have been more revealing if it included cirrhosis as a death risk factor.
References
1. Bedimo R, Westfall A, Drechsler H, Maalouf N. HCV co-infection is associated with a high risk of osteoporotic fractures among HIV-infected patients. XVIII International AIDS Conference. July 18-23, 2010. Vienna. Abstract TUAB0104.
2. Collin F, Duval X, Le Moing V, et al. Ten-year incidence and risk factors of bone fractures in a cohort of treated HIV1-infected adults. AIDS. 2009;23:1021-1024. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2855855/?tool=pubmed.
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