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Low Trabecular BMD, High TNF-Alpha in Women
With HIV/HCV vs Only HIV or HCV
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IDWeek 2014, October 8-12, 2014, Philadelphia
Mark Mascolini
Volumetric trabecular bone mineral density (vBMD) was lower in women with HIV/HCV coinfection than in those with HIV or HCV alone, according to results of a 151-woman three-way comparison [1]. HIV/HCV-coinfected women also had more inflammation indicated by higher TNF-alpha levels, a finding leading the researchers to suggest that "amelioration of TNF-alpha inflammation may decrease bone loss."
University of Pennsylvania researchers noted that people with HIV/HCV coinfection have lower BMD and higher fracture rates than people infected with only one of these viruses. And these associations are stronger for women than men. Because the mechanisms of BMD and fracture with HIV/HCV coinfection are poorly understood, the University of Pennsylvania team conducted this study.
The cross-sectional analysis involved 50 antiretroviral-treated women with HIV/HCV coinfection, 51 infected with HCV alone, and 50 antiretroviral-treated women with HIV alone. The investigators used peripheral quantitative computed tomography (pQCT) to generate three-dimensional measures of volumetric BMD (vBMD) and several cortical bone dimensions: cortical thickness, cortical area, periosteal circumference, and endosteal circumference. They used whole-body DXA scans to measure whole-body fat and appendicular lean mass. Finally, they used data from 263 women without HIV or liver disease to create age- and race-specific Z-scores for fat mass and appendicular lean mass.
All women were 18 or older. Those with HCV had genotype 1 infection and staged liver fibrosis; those with HIV were on a stable antiretroviral regimen for at least 3 months and had a viral load below 1000 copies. The researchers excluded pregnant or breastfeeding women, those with prior HCV therapy, and those with conditions affecting nutrition or bone health.
Median ages of women with HIV/HCV, HCV, HIV, or neither infection were 51, 55, 47, and 47. Respective proportions of blacks were 78%, 84%, 84%, and 42%, while median body mass index stood at 27.2, 31.3, 31.9 and 25.7 kg/m2. Women with HIV/HCV included a higher proportion of current smokers (80%) than women with HCV, HIV, or neither infection (49%, 32%, 13%). Almost one quarter of women with HIV/HCV or HCV alone had METAVIR stage 3-4 liver fibrosis. About 80% of women with HIV had a viral load below 75 copies, and about three quarters were taking tenofovir.
Mean pQCT Z-score was significantly lower in women with HIV/HCV coinfection than in the healthy comparison group for trabecular vBMD (-0.85 versus -0.01, P < 0.001), cortical area (-0.61 versus 0.03, P < 0.001), cortical thickness (-0.77 versus 0.00, P < 0.001), and endosteal circumference (+0.67 versus 0.07, P < 0.001). Greater mean endosteal circumference with HIV/HCV than in healthy controls and comparable periosteal circumference explained decreased cortical dimensions in coinfected women. These significant differences remained after adjustment for smoking, total physical activity, appendicular lean mass Z-score, and fat mass Z-score.
Mean trabecular vBMD Z-scores were significantly lower in coinfected women than in women with HCV alone (P = 0.004) or HIV alone (P < 0.001). In women with HCV, mean pQCT Z-scores were significantly greater in those with stage 0-2 fibrosis versus stage 3-4 fibrosis for trabecular vBMD (P = 0.04), cortical area (P = 0.05), and cortical thickness (P = 0.02).
There were no significant differences across the HIV and HCV groups for vitamin D, parathyroid hormone, or the inflammatory cytokines IL-1 beta or IL-6. But median TNF-alpha, another inflammatory cytokine, was significantly higher with HIV/HCV than with HCV alone (3.11 versus 2.63 pg/mL, P = 0.04) or HIV alone (3.11 versus 2.05 pg/mL, P < 0.001).
The researchers pointed out several limitations to their analysis: its cross-sectional design; lack of data on HIV or HCV duration; inability to confirm HIV or HCV status in the healthy reference group; and generalizability of results to men. With these limitations in mind, the investigators concluded that, compared with the healthy reference group, coinfected women had lower trabecular vBMD and cortical thinning, a pattern observed in inflammatory diseases. Compared with HIV- or HCV-monoinfected women, those with coinfection had lower trabecular vBMD and increased TNF-alpha, an inflammation marker.
Reference
1. Lo Re III V, Lynn K, Stumm E, et al. Structural bone deficits in HIV/HCV, HCV-monoinfected, and HIV-monoinfected women. IDWeek 2014. October 8-12, 2014, Philadelphia. Abstract 645.
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