Date Published: March 21, 2019
Publisher: Public Library of Science
Author(s): Tara McGinty, Aoife G. Cotter, Caroline A. Sabin, Alan Macken, Eoin Kavanagh, Juliet Compston, Gerard Sheehan, John Lambert, Patrick W. G. Mallon, Robert Daniel Blank.
Increased prevalence of low bone mineral density (BMD) and increased fracture incidence are observed in persons living with HIV (PLWH). The trabecular bone score (TBS) is a novel index of bone microarchitecture which improves fracture prediction independent of BMD.
The HIV UPBEAT study is a single centre, prospective cohort study that enrolled subjects with and without HIV from similar sociodemographic backgrounds for annual assessments of bone health. TBS was derived from lumbar spine (LS) dual-energy X-ray absorptiometry images. Univariate and multivariable linear regression was used to assess relationships between baseline TBS, BMD, sociodemographic and clinical factors.
463 subjects (201 HIV positive) were included; PLWH were younger and more likely male, of non-African ethnicity and current smokers. HIV was associated with a mean reduction of 0.037 [-0.060, -0.013] (p = 0.002) in TBS. Lower TBS was also associated with male gender, non-African ethnicity, current smoking status and lower LS BMD. HIV remained associated with lower TBS after adjustment for LS BMD, age, gender and ethnicity. However, adjustment for current smoking significantly attenuated the association between HIV and TBS, with further adjustment for higher bone turnover markers largely explaining any residual association. Among the sub-group of PLWH, exposure to protease inhibitors and lower nadir CD4+ T-cell counts were both predictors of lower TBS.
PLWH have lower TBS independent of LS BMD. However, this is largely explained by higher current smoking rates and higher bone turnover in those with HIV. Exposure to PI, but not tenofovir disproxil fumarate, also contributed to lower TBS in those with HIV.
Advances in HIV therapy and care have led to significant gains in life expectancy over the past decade . This success has been accompanied by an increasing burden of non-AIDS and age-related co-morbidities such cardiovascular disease, kidney disease and bone disease [2–5].
This is one of the largest studies examining TBS in a diverse cohort of subjects with and without HIV recruited from similar sociodemographic and geographical backgrounds. We demonstrate that lower TBS in those with HIV is largely driven by current smoking status and altered bone turnover. Additionally, within the HIV group, exposure to PIs, but not TDF, and lower nadir CD4+ T-cell count were both independently associated with lower TBS. This finding highlights the dual contribution of immune status and exposure to ART to bone health.