Bone Quality in Relation to HIV and Antiretroviral Drugs

Updates on bone health in people living with HIV: global impact, prediction tools, and treatment

PURPOSE OF REVIEW

Osteoporosis and fragility fractures continue to be a concern for aging people living with HIV (PLWH), despite newer antiretroviral (ART) formulations that are associated with reduced bone toxicity. The aim of this review is to evaluate recent literature focusing on estimates of osteoporosis and fractures in various study populations, efficacy of current fracture risk assessment tools, and interventions to improve bone health outcomes.

RECENT FINDINGS

Prevalence of low bone mineral density (BMD) remains higher among PLWH globally, with new estimates ranging from 24 to 59%. The FRAX tool underestimates rate of major osteoporotic fractures in PLWH; some studies suggest that modifications can improve accuracy. Bone quality assessments with trabecular bone score may also improve prediction of vertebral fractures in PLWH. Preexposure prophylaxis (PrEP) with TDF/FTC is generally safe for maternal and infant bone health. Denosumab treatment effectively improves bone mass in PLWH.

SUMMARY

Despite advancements in ART, osteoporosis and fragility fractures remain common among PLWH. There is a need for continued research on development of fracture risk assessment tools including use of clinical data, imaging studies and biomarkers, and implementation of preventive and treatment strategies for at-risk subgroups.

Evaluation of bone mineral density and its influencing factors in patients infected with HIV under antiretroviral therapy

BACKGROUND

Reduced Bone Mineral Density (BMD) has been linked to Human Immunodeficiency Virus (HIV) infection and treatment. There is a lack of information regarding the osteoporosis status of middle-aged patients with HIV in Iran, despite the fact that Antiretroviral Therapy (ART) is widely accessible.

OBJECTIVE

The purpose of this cross-sectional study was to assess the BMD status and low BMD risk factors in patients with HIV under ART living in Iran.

METHODS

Data were collected from individuals diagnosed with HIV aged 30-50, receiving ART for at least 6 months. Dual-energy X-ray absorptiometry scans assessed BMD in femoral neck, total hip, and lumbar regions. Pearson's correlation coefficients identified relationships between BMD and demographic and laboratory predictors. Univariable and multivariable logistic regression models assessed predictors of low lumbar BMD.

RESULTS

Among 80 HIV-infected individuals (mean age: 41.1 ± 5.6 years, 60.4% male), 15% exhibited low BMD in the lumbar spine and 3.75% in the femoral neck. Serum phosphate levels were negatively correlated with BMD across the femoral neck, total hip, and lumbar regions (e.g., lumbar BMD: r = -0.24, p = 0.03). Parathyroid hormone (PTH) showed negative correlations with femoral neck and total hip BMD (r = -0.26, p = 0.01; r = -0.29, p = 0.01, respectively). Estradiol positively correlated with lumbar BMD in females (r = 0.36, p = 0.04), and BMI positively correlated with BMD in all regions (e.g., lumbar: r = 0.41, p = 0.001). Testosterone was inversely associated with the odds of lumbar low BMD (OR [95% CI] = 0.79 [0.62-0.96], p = 0.02). Duration of HIV or treatment, CD4 levels, and viral load were not significantly associated with BMD.

CONCLUSION

This study highlights the multifactorial nature of BMD changes in individuals living with HIV. By identifying correlations between metabolic, hormonal, and disease-related factors and bone health, our findings bring attention to an often-overlooked aspect of HIV management, that is patients with HIV may benefit from routine BMD screening, as it could help identify early risks of low BMD.

Bone Loss and Fractures in Post-Menopausal Women Living with HIV: A Narrative Review

INTRODUCTION

Post-menopausal women living with Human Immunodeficiency Virus (WLHIV) face an increased risk of bone fractures due to the relationship between HIV-related factors and menopause. This narrative review aims to summarise the current knowledge about fracture risk among post-menopausal WLHIV in particular looking at hormonal changes, combined antiretroviral therapy (cART), lifestyle factors, and psychosocial implications. We also profiled a summary of the significant, recent studies of post-menopausal WLHIV residing in low-income countries (LIC).

METHODS

A thorough search of the literature was performed across PubMed, Medline, Scopus, and Google Scholar, focussing on studies published between 2000 and 2024. Inclusion criteria entailed original research, reviews, and meta-analyses addressing bone mineral density (BMD), fracture incidence, and related risk factors in post-menopausal WLHIV.

RESULTS

The review identified 223 relevant studies. Post-menopausal WLHIV exhibit significantly lower BMD and higher fracture rates compared to both HIV-negative post-menopausal women and pre-menopausal WLHIV. cART, particularly tenofovir disoproxil fumarate (TDF), contributes to reduced BMD. Menopausal status exacerbates this risk through decreased oestrogen levels, leading to increased bone resorption. Moreover, lifestyle choices such as smoking, alcohol consumption, and low physical activity are more prevalent in PWHIV, which further elevates fracture risk. Different psychosocial factors may make WLWHIV more vulnerable at this stage of their life, such as depression, isolation, stigma, and housing and nutritional issues. Women living in LICs face a variety of challenges in accessing HIV care. There are gaps in research related to the prevalence of osteoporosis and bone loss in post-menopausal WLHIV in LICs.

CONCLUSION

Post-menopausal women living with HIV face a significantly higher risk of bone loss and fractures due to the combined effects of HIV and menopause. Antiretroviral therapy (particularly TDF), lifestyle factors, and psychosocial challenges exacerbate this risk. There is a need for careful selection of cART, hormone replacement therapy (HRT), and emerging treatments such as Abaloparatide. A holistic approach including lifestyle changes and psychosocial support is crucial to reduce fracture risk in WLHIV, especially in low-income countries.

Bone Tissue Changes in Individuals Living with HIV/AIDS: The Importance of a Hierarchical Approach in Investigating Bone Fragility

Skeletal alterations and their complications can significantly impact the quality of life and overall prognosis of patients living with HIV (PLWHIV). Considering skeletal alterations are often asymptomatic and unapparent during routine clinical evaluation, these conditions are frequently overlooked in the clinical management of PLWHIV. However, since the use of combined antiretroviral therapy (cART) has increased life expectancy in PLWHIV effectively, osteopenia, osteoporosis, and bone fragility are now considered to have a major health impact, with a substantial increase in healthcare costs. This narrative literature review aimed to provide a comprehensive overview of the contemporary literature related to bone changes in PLWHIV, focusing on the importance of taking a multi-scale approach in the assessment of bone hierarchical organization. Even though a low bone mineral density is frequently reported in PLWHIV, numerous ambiguities still remain to be solved. Recent data suggest that assessment of other bone properties (on various levels of the bone structure) could contribute to our understanding of bone fragility determinants in these individuals. Special attention is needed for women living with HIV/AIDS since a postmenopausal status was described as an important factor that contributes to skeletal alterations in this population. Further research on complex etiopathogenetic mechanisms underlying bone alterations in PLWHIV may lead to the development of new therapeutic approaches specifically designed to reduce the health burden associated with skeletal disorders in this population. A major challenge in the clinical management of PLWHIV lies in the adverse skeletal effects of some frequently prescribed cART regimens (e.g., regimens containing tenofovir disoproxil fumarate), which may require a switch to other pharmacological approaches for maintained HIV infection (e.g., regimens containing tenofovir alafenamide). Taken together, the findings are indicative that the HIV/AIDS status should be taken into consideration when designing new guidelines and strategies for individualized prevention, diagnosis, and treatment of increased bone fragility.

The anti-HIV drug abacavir stimulates β-catenin activity in osteoblast lineage cells

Bone mineral density (BMD) loss in people living with HIV occurs with the initiation of combined antiretroviral therapy (cART), particularly with tenofovir disoproxil fumarate (TDF) containing cART. Switching from TDF to abacavir (ABC) or dolutegravir (DTG) leads to increased BMD. Whether BMD gains are due to cessation of TDF or anabolic effects of ABC or DTG is unclear. We investigated the effects of ABC and DTG on osteoblast lineage cells in vitro and in vivo. Primary human osteoblasts and male C57BL/6 mice were treated with individual antiretrovirals (ARVs) or a combination of ABC/DTG/lamivudine (3TC). Nearly all ARVs and cART inhibited osteogenic activity in vitro. Due to the importance of Wnt/β-catenin in bone formation, we further investigated ARV effects on the Wnt/β-catenin pathway. ABC, alone and as part of ABC/DTG/3TC, increased osteoblastic β-catenin activity as indicated by increased TOPFlash activity, hypo-phosphorylated (active) β-catenin staining, and β-catenin targeted gene expression. Mice treated with TDF had decreased lumbar spine BMD and trabecular connectivity density in the vertebrae, while those treated with ABC/DTG/3TC reduced cortical area and thickness in the femur. Mice treated with ABC alone had no bone structural changes, increased circulating levels of the bone formation marker, P1NP, and elevated expression of the Wnt/β-catenin target gene, Lef1, in osteocyte enriched samples. Further, bones from ARV-treated mice were isolated to evaluate ARV distribution. All ARVs were detected in the bone tissue, which was inclusive of bone marrow, but when bone marrow was removed, only TDF, ABC, and DTG were detected at ~0.1% of the circulating levels. Overall, our findings demonstrate that ABC activates Wnt/β-catenin signaling, but whether this leads to increased bone formation requires further study. Assessing the impact of ARVs on bone is critical to informing ARV selection and/or discovery of regimens that do not negatively impact the skeleton.

Evaluation of the mandibular condylar bone microarchitecture in people living with HIV

OBJECTIVES

People living with HIV (PLWH) have been shown to have lower bone density at the spine, hip, and radius. However, whether a similar bone phenotype is seen in craniofacial bones is not known. The goal of this study was to evaluate the bone microarchitecture of the mandibular condyle in PLWH.

METHODS

We recruited 212 participants, which included 88 HIV-negative participants and 124 PLWH on combination antiretroviral therapy with virological suppression from a single academic center. Each participant filled out a validated temporomandibular disorder (TMD) pain screening questionnaire and had cone beam computed tomography (CBCT) of their mandibular condyles. Qualitative radiographic evidence of temporomandibular joint disorders-osteoarthritis (TMJD-OA) assessment and quantitative microarchitecture analysis of their mandibular condylar bones were conducted.

RESULTS

There was no statistically significant difference in either self-reported TMD or in radiographic evidence of TMJD-OA in PLWH compared with HIV-negative controls. Linear regression analysis revealed that positive HIV status remained significantly associated with increased trabecular thickness, decreased cortical porosity, and increased cortical bone volume fraction after adjusting for race, diabetes, sex, and age.

CONCLUSION

PLWH have increased mandibular condylar trabecular bone thickness and cortical bone volume fraction compared with HIV-negative controls.

Bone Disease in HIV: Need for Early Diagnosis and Prevention

The transformation of HIV into a manageable chronic condition has unveiled new clinical challenges associated with aging-related pathologies, including bone disease. This review explores the intricate relationship between HIV, antiretroviral therapy (ART), and bone disease, highlighting the necessity of early diagnosis and preventative strategies to mitigate the increased risk of osteopenia, osteoporosis, and fractures in people living with HIV (PLWHIV). It synthesizes the current literature to elucidate the multifactorial etiology of bone pathology in this population, that includes direct viral effects, chronic immune activation, ART-associated risks, and the impact of traditional risk factors for bone loss. Through a critical examination of modern diagnostic methods, lifestyle modifications, evidence-based preventive actions, and pharmacological treatments, the necessity for comprehensive management is highlighted, along with recommendations for integrated healthcare approaches vital for achieving optimal patient outcomes. By advocating for a proactive, patient-centered, and multidisciplinary strategy, this review proposes a plan to integrate bone health into standard HIV care through active risk identification, vigilant screening, effective preventive measures, tailored treatments, and informed decision-making, in an effort to ultimately enhance the quality of life for PLWHIV.

Fracture Risk and Association With TDF Use Among People With HIV in Large Integrated Health Systems

BACKGROUND

Greater decline in bone health among people with HIV (PWH) has been documented but fracture risk and the impact of specific antiretroviral therapy (ART) regimens remain unclear.

SETTING

Retrospective analyses of electronic health record data from 3 US integrated health care systems.

METHODS

Fracture incidence was compared between PWH aged 40 years or older without prior fracture and demographically matched people without HIV (PWoH), stratified by age, sex, and race/ethnicity. Multivariable Cox proportional hazards models were used to estimate fracture risk associated with HIV infection. The association of tenofovir disoproxil fumarate (TDF) use and fracture risk was evaluated in a subset of PWH initiating ART.

RESULTS

Incidence of fracture was higher in PWH [13.6/1000 person-years, 95% confidence interval (CI): 13.0 to 14.3, n = 24,308] compared with PWoH (9.5, 95% CI: 9.4 to 9.7, n = 247,313). Compared with PWoH, the adjusted hazard ratio (aHR) for fracture among PWH was 1.24 (95% CI: 1.18 to 1.31). The association between HIV infection and fracture risk increased with age, with the lowest aHR (1.17, 95% CI: 1.10 to 1.25) among those aged 40-49 years and the highest aHR (1.89, 95% CI: 1.30 to 2.76) among those aged 70 years or older. Among PWH initiating ART (n = 6504), TDF was not associated with significant increase in fracture risk compared with non-TDF regimens (aHR: 1.18, 95% CI: 0.89 to 1.58).

CONCLUSIONS

Among people aged 40 years or older, HIV infection is associated with increased risk of fractures. Bone health screening from the age of 40 years may be beneficial for PWH. Large cohort studies with longer follow-up are needed to evaluate TDF effect and the potential benefit of early screening.

Contribution of viral and bacterial infections to senescence and immunosenescence

Cellular senescence is a key biological process characterized by irreversible cell cycle arrest. The accumulation of senescent cells creates a pro-inflammatory environment that can negatively affect tissue functions and may promote the development of aging-related diseases. Typical biomarkers related to senescence include senescence-associated β-galactosidase activity, histone H2A.X phosphorylation at serine139 (γH2A.X), and senescence-associated heterochromatin foci (SAHF) with heterochromatin protein 1γ (HP-1γ protein) Moreover, immune cells undergoing senescence, which is known as immunosenescence, can affect innate and adaptative immune functions and may elicit detrimental effects over the host's susceptibility to infectious diseases. Although associations between senescence and pathogens have been reported, clear links between both, and the related molecular mechanisms involved remain to be determined. Furthermore, it remains to be determined whether infections effectively induce senescence, the impact of senescence and immunosenescence over infections, or if both events coincidently share common molecular markers, such as γH2A.X and p53. Here, we review and discuss the most recent reports that describe cellular hallmarks and biomarkers related to senescence in immune and non-immune cells in the context of infections, seeking to better understand their relationships. Related literature was searched in Pubmed and Google Scholar databases with search terms related to the sections and subsections of this review.