Greater decrease in bone mineral density with protease inhibitor regimens compared with nonnucleoside reverse transcriptase inhibitor regimens in HIV-1 infected naive patients

Ageing with HIV

The population of people living with HIV (PLWH) is growing older with an estimated 4 million over the age of 50 years, a figure which has doubled since the introduction of effective antiretroviral therapy (ART) and which is increasing globally. Despite effective ART, PLWH still experience excess morbidity and mortality compared to the general population with increased prevalence of age-related, non-AIDS illnesses (NAI) such as cardiovascular disease, malignancies, cognitive impairment and reduced bone mineral density, which impact disability and everyday functioning. This review will discuss the challenges presented by comorbidities in ageing PLWH and discuss the aetiology and management of age-related illnesses in this vulnerable population.

Protecting bone in long-term HIV positive patients receiving antiretrovirals

INTRODUCTION

As the population of people living with HIV ages, the increase in non-AIDs morbidities is expected to increase in parallel. Maintaining bone health in those with HIV will be an important area of focus for the HIV clinician to prevent the morbidity and mortality associated with fragility fractures, the principal clinical sequela of low bone mineral density (BMD). Rates of fractures and prevalence of low bone mineral density, a risk factor for future fragility fractures, are already increased in the HIV positive population.

AREAS COVERED

This review examines the strategies to maintain bone health in those living with HIV from screening through to managing those with established low BMD or fracture, including the role for choice of or modification of antiretroviral therapy to maintain bone health. Expert commentary: The increasing complexity of managing bone health in the age of succesful antiretroviral therapy and an aging patient population as well as future perspectives which may help achieve the long term aim of minimising the impact of low BMD in those with HIV are discussed and explored.

Switching from a ritonavir-boosted PI to dolutegravir as an alternative strategy in virologically suppressed HIV-infected individuals

Background

Switching from PIs to dolutegravir in virologically suppressed HIV-infected individuals has not been assessed.

Objectives

The principal aim was to assess the evolution of bone mineral density (BMD) when switching from a ritonavir-boosted PI to dolutegravir in HIV-infected patients with osteopenia or osteoporosis. The secondary objective was to assess the antiviral efficacy and safety of the switch therapy.

Methods

This randomized, multicentre study assessed changes in BMD, bone turnover markers, and antiviral efficacy and safety in 73 virologically suppressed patients with osteopenia/osteoporosis taking a ritonavir-boosted PI plus abacavir/lamivudine who were randomized to switch from PI to dolutegravir (DOLU group, n  =   37) or continue with a PI (PI group, n  =   36). Clinical Trials: NCT02577042.

Results

One and three patients from the DOLU and PI groups, respectively, withdrew prematurely (unrelated to treatment). At 48 weeks, 97.3% versus 91.7%, respectively, maintained viral suppression (snapshot analysis, ITT, M = F). No significant differences were seen between the groups in percentage change from baseline to week 48 in femoral ( P  =   0.56) and lumbar spine ( P  =   0.29) BMD, although lumbar spine BMD improved by 1.43% (-1.36; 2.92) in the DOLU group [0.12% (-2.83; 2.89) in the PI group]. Bone marker values did not vary significantly. At week 48, triglycerides were lower ( P  <   0.001) and HDL cholesterol higher ( P  =   0.027) in the DOLU group.

Conclusions

Dolutegravir + Kivexa ® was safe and well-tolerated in virologically suppressed patients receiving a PI-based regimen. The lipid profile was better, albeit without significant changes in BMD, probably because of the short follow-up.

HIV Infection and Bone Abnormalities

More than 36 million people are living with human immunodeficiency virus (HIV) infection worldwide and 50% of them have access to antiretroviral therapy (ART). While recent advances in HIV therapy have reduced the viral load, restored CD4 T cell counts and decreased opportunistic infections, several bone-related abnormalities such as low bone mineral density (BMD), osteoporosis, osteopenia, osteomalacia and fractures have emerged in HIV-infected individuals. Of all classes of antiretroviral agents, HIV protease inhibitors used in ART combination showed a higher frequency of osteopenia, osteoporosis and low BMD in HIV-infected patients. Although the mechanisms of HIV and/or ART associated bone abnormalities are not known, it is believed that the damage is caused by a complex interaction of T lymphocytes with osteoclasts and osteoblasts, likely influenced by both HIV and ART. In addition, infection of osteoclasts and bone marrow stromal cells by HIV, including HIV Gp120 induced apoptosis of osteoblasts and release of proinflammatory cytokines have been implicated in impairment of bone development and maturation. Several of the newer antiretroviral agents currently used in ART combination, including the widely used tenofovir in different formulations show relative adverse effects on BMD. In this context, switching the HIV-regimen from tenofovir disoproxil fumarate (TDF) to tenofovir alafenamide (TAF) showed improvement in BMD of HIV-infected patients. In addition, inclusion of integrase inhibitor in ART combination is associated with improved BMD in patients. Furthermore, supplementation of vitamin D and calcium with the initiation of ART may mitigate bone loss. Therefore, levels of vitamin D and calcium should be part of the evaluation of HIV-infected patients.

Bone mineral density in people living with HIV: a narrative review of the literature

Bone health status is largely absent in South Africa, the main reasons being the absence and cost-effectiveness of specific screening equipment for assessing bone mineral density (BMD). Various risk factors seem to play a role, some of which can be modified to change bone health status. Urbanisation is also a public health concern. Changing nutritional, as well as social behaviour, play integral roles in the prevalence and incidence of decreased BMD. Furthermore, human immunodeficiency virus (HIV) specifically, has a negative impact on BMD and although highly active antiretroviral therapy increases the prognosis for HIV-infected individuals, BMD still seem to decrease further. Dual energy X-ray absorptiometry is considered the gold standard for BMD assessment; however, recent developments have provided more cost-effective screening methods, among which heel quantitative ultrasound appears to be the most widely used in resource limited countries such as South Africa.

HIV-associated cellular senescence: A contributor to accelerated aging

Due to the advent of antiretroviral therapy HIV is no longer a terminal disease and the HIV infected patients are becoming increasingly older. While this is a major success, with increasing age comes an increased risk for disease. The age-related comorbidities that HIV infected patients experience suggest that they suffer from accelerated aging. One possible contributor to this accelerated aging is cellular senescence, an age-associated response that can occur prematurely in response to stress, and that is emerging as a contributor to disease and aging. HIV patients experience several stressors such as the virus itself, antiretroviral drugs and to a lesser extent, substance abuse that can induce cellular senescence. This review summarizes the current knowledge of senescence induction in response to these stressors and their relation to the comorbidities in HIV patients. Cellular senescence may be a possible therapeutic target for these comorbidities.

High FGF21 levels are associated with altered bone homeostasis in HIV-1-infected patients

BACKGROUND

Fibroblast growth factor-21 (FGF21) has emerged as an important regulator of glucose, lipid, and body weight homeostasis. However, recent experimental studies have reported that increased FGF21 levels may lead to bone loss.

OBJECTIVE

To assess the relationship of serum FGF21 levels and altered bone homeostasis in HIV-1-infected patients.

DESIGN

Cross-sectional study of 137 HIV-1-infected patients and 35 healthy controls conducted at the Hospital de la Santa Creu i Sant Pau, Barcelona. Among HIV-1-infected patients, 35 were untreated (naïve), 43 were treated with antiretrovirals (HIV-1/ART) with no lipodystrophy, and 59 patients were HIV-1/ART and experienced lipodystrophy. Bone mineral density (BMD) and content (BMC) were assessed using dual-energy X-ray absorptiometry. Serum levels of FGF21, receptor activator of nuclear factor (NF)-KB ligand (RANKL), and C-telopeptide of type-I collagen (CTX-1) were measured by enzyme-linked immunosorbent assays. Serum levels of osteocalcin, osteoprotegerin, leptin, tumor necrosis factor-α, interleukin-6, interleukin-8, and monocyte chemoattractant protein-1 were determined using an antibody-linked, fluorescently labeled microsphere bead-based multiplex analysis system.

RESULTS

Alterations in bone parameters and bone homeostasis marker levels were consistent with higher turnover and bone loss in HIV-1 infected patients. FGF21 correlated negatively with BMD and BMC. FGF21 correlated positively with serum levels of osteoprotegerin and CTX-1, as well as with the CTX-1/osteocalcin ratio.

CONCLUSIONS

Elevated FGF21 levels are associated with poor bone homeostasis in HIV-1-infected patients. Increases in FGF21 serum level may be an indicator not only of metabolic derangement but it may also serve as a biomarker of altered bone homeostasis in HIV-1 infected patients.

Predictors of longitudinal change in bone mineral density in a cohort of HIV-positive and negative patients

OBJECTIVE

Although low bone mineral density (BMD) is prevalent in HIV, changes in BMD over time remain unclear. We aimed to compare rates of, and factors associated with, BMD change between HIV-positive and HIV-negative patients.

METHODS

In a prospective, 3-year cohort, HIV-positive and HIV-negative patients provided annual demographic and clinical data, fasting bloods, and dual x-ray absorptiometry. Using longitudinal mixed models we compared and determined predictors of rate of change in BMD.

RESULTS

Of 384 study participants (45.8% HIV positive), 120 contributed two and 264 contributed three BMD measurements. Those with HIV were younger [median interquartile range 39 (34-46) vs. 43 (35-50) years; P = 0.04], more often men (61 vs. 46%; P = 0.003), and less likely Caucasian (61 vs. 82%; P < 0.001). Although BMD was lower in those with HIV, BMD declined in both groups, with nonsignificant between-group difference in rate of BMD change over time. Within the HIV group, starting antiretroviral therapy (ART) within 3 months of enrolment was associated with greater BMD decline at all anatomical sites (all P < 0.001). Age more than 30 years, Caucasian ethnicity, and not being on ART during follow-up were associated with greater decline and higher parathyroid hormone associated with a smaller decline in BMD at the femoral neck. We found no association between BMD change and exposure to tenofovir disoproxil fumarate or protease inhibitors.

CONCLUSION

We observed no difference in rate of BMD decline regardless of HIV status and in HIV-positive patient, having started ART within the previous 3 months was the only factor associated with greater BMD decline at all three sites.

Bone Loss in HIV Infection

Human immunodeficiency virus (HIV) infection is an established risk factor for low bone mineral density (BMD) and subsequent fracture, and treatment with combination antiretroviral therapy (cART) leads to additional BMD loss, particularly in the first 1-2 years of therapy. The prevalence of low BMD and fragility fracture is expected to increase as the HIV-infected population ages with successful treatment with cART. Mechanisms of bone loss in the setting of HIV infection are likely multifactorial, and include viral, host, and immune effects, as well as direct and indirect effects of cART, particularly tenofovir disoproxil fumarate (TDF) and the protease inhibitors (PIs). Emerging data indicate that BMD loss following cART initiation can be mitigated by prophylaxis with either long-acting bisphosphonates or vitamin D and calcium supplementation. In addition, newer antiretrovirals, particularly the integrase strand transfer inhibitors and tenofovir alafenamide (TAF), are associated with less intense bone loss than PIs and TDF. However, further studies are needed to establish optimal bone sparing cART regimens, appropriate screening intervals, and preventive measures to address the rising prevalence of fragility bone disease in the HIV population.

Viability of primary osteoblasts after treatment with tenofovir alafenamide: Lack of cytotoxicity at clinically relevant drug concentrations

Tenofovir alafenamide (TAF) is a phosphonoamidate prodrug of the nucleotide HIV reverse transcriptase inhibitor tenofovir (TFV). TAF is approved for the treatment of HIV-1 infection as part of the single-tablet regimen containing elvitegravir, cobicistat, emtricitabine, and TAF. When dosed once-daily, TAF results in approximately 90% lower levels of plasma TFV and a 4-fold increase in intracellular TFV-diphosphate (TFV-DP) in PBMCs compared with the TFV prodrug tenofovir disoproxil fumarate (TDF). Several antiretrovirals, including TDF, have been associated with bone mineral density decreases in patients; the effect of clinically relevant TAF concentrations on primary osteoblast viability was therefore assessed in vitro. Studies in PBMCs determined that a 2-hour TAF exposure at concentrations similar to human plasma Cmax achieved intracellular TFV-DP levels comparable to those observed after the maximum recommended human dose of 25 mg TAF. Comparable intracellular TFV-DP levels were achieved in primary osteoblasts with 2-hour TAF exposure daily for 3 days at concentrations similar to those used for PBMCs (100-400 nM). No change in cell viability was observed in either primary osteoblasts or PBMCs. The mean TAF CC50 in primary osteoblasts after 3 days of daily 2-hour pulses was >500 μM, which is >1033 times higher than the TAF maximum recommended human dose plasma Cmax. In summary, primary osteoblasts were not preferentially loaded by TAF compared with PBMCs, with comparable TFV-DP levels achieved in both cell types. Furthermore, there was no impact on osteoblast cell viability at clinically relevant TAF concentrations.

Bone health in HIV and hepatitis B or C infections

Chronic infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV) add to age-dependent bone loss and may contribute to lower bone strength in the elderly. In this review, we report recent highlights on the epidemiology of bone fragility in chronic viral infections with HIV, HCV and HBV, its physiopathology and discuss the interference of antiviral therapies with bone metabolism. Chronic infections influence bone through the interactions between risk factors for bone fragility and falls (which are highly prevalent in infected patients), virus activity and antiviral drugs. HIV-infected patients are at increased risk of fracture and the risk is higher in cases of co-infection with HIV and untreated chronic viral hepatitis. In HIV patients, the majority of bone loss occurs during virus activity and at initiation of antiretroviral therapy (ART). However, long-term elderly HIV-infected patients on successful ART display bone microstructure alterations only partially captured by dual energy X-ray absorptiometry (DXA). Bone loss is associated with an increase of bone resorption, reflecting the upregulation of the receptor activator of nuclear factor-kappaB ligand (RANKL) and osteoprotegerin (OPG) pathways via a crosstalk between virus activity, inflammation and the immune system. The use of some antiviral drugs, such as tenofovir (controlling both HBV and HIV infections) or protease inhibitors, may be associated with higher bone toxicity. The reduction of tenofovir plasma concentrations with the implementation of tenofovir alafenamide (TAF) attenuates bone mineral density (BMD) loss but it remains unknown whether it will contribute to reducing fracture risk in long-term HIV-treated patients. Moreover, to what extent the new direct-acting agents for treatment of HCV, including nucleotide inhibitors and protease inhibitors, may affect bone health similarly as ART in HIV should be investigated.

Factors associated with fractures in HIV-infected persons: which factors matter?

This study aims to determine what factors are associated with increased risk of fracture among patients with HIV, in particular whether an important medication used to treat HIV, tenofovir, is associated with fracture. Our study found that while co-infection with hepatitis C and markers of HIV severity were associated with fracture, tenofovir was not.

INTRODUCTION

Growing evidence suggests that tenofovir disoproxil fumarate decreases bone density among patients with HIV, but there are conflicting reports as to whether this decrease in bone density translates to higher fracture risk. We aimed to determine what factors were associated with an increased risk of fracture for patients with HIV, in particular whether tenofovir is associated with elevated fracture risk.

METHODS

We conducted a retrospective cohort study at two tertiary care hospitals in Boston, MA, between 2001 and 2012 to determine whether tenofovir use is associated with elevated all-site fracture risk, as compared to other antiretroviral medications. We also examined other potential factors associated with fracture among patients with HIV.

RESULTS

We identified 1981 HIV-infected patients who had at some point used tenofovir and 682 patients who had not. The mean age was 43 years, and 72 % were male. The hepatitis C co-infection rate was 28 %, about 40 % had nadir CD4 count <200, and about 40 % had a history of an AIDS-defining illness. We did not find an association between risk of fracture and tenofovir disoproxil fumarate (TDF) (adjusted RR (aRR) 0.8, 95 % CI 0.6-1.1). However, co-infection with hepatitis C did increase risk of fracture (aRR 1.6, 95 % CI 1.1-2.3), as did nadir CD4 count <200 (aRR 3.1, 95 % CI 1.9-5.0) and history of AIDS-defining illness (aRR 1.6, 95 % CI 1.1-2.2).

CONCLUSION

There was no association found between fracture and tenofovir use, but there were associations between co-infection with hepatitis C and markers of advanced HIV disease and fracture.

Alveolar bone in human immunodeficiency virus infection: is it changed by long-term antiretroviral therapy?

BACKGROUND

Previous studies have reported that human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) can lead to osteoporosis in HIV-infected individuals. However, their effects on alveolar bone are not well established. The objective of this study was to measure the alveolar bone mineral density (BMD) of HIV-infected patients, with and without antiretroviral therapy (ART), in comparison with that of HIV-free individuals, and to determine factors associated with the BMD of alveolar bone.

METHODS

A cross-sectional study was performed in non-HIV-infected individuals and HIV-infected individuals, with and without ART. Medical status and clinical data were recorded. Periapical radiographs of maxillary and mandibular right premolars were analysed for changes of alveolar BMD based on HIV/ART status. Other factors associated with the changes of alveolar BMD were explored using a parametric multivariate analysis of covariance (MANCOVA).

RESULTS

One-hundred and one HIV-infected individuals receiving ART (age range: 23-57 years; median age 39 years), 58 receiving no ART (age range: 20-59 years; median age 34 years) and 50 HIV-negative individuals (age range: 19-59 years; median age 36 years) were enrolled. Neither HIV status nor use of ART was significantly associated with the changes of alveolar BMD.

CONCLUSION

Although osteoporosis has been reported in HIV-infected individuals treated with ART, alveolar BMD does not appear to be changed as a result of the infection, or use of ART.

HIV infection and bone disease

The success of antiretroviral therapy in treating HIV infection has greatly prolonged life expectancy in affected individuals, transforming the disease into a chronic condition. A number of HIV-associated non-AIDS comorbidities have emerged in the ageing HIV-infected population, including osteoporosis and increased risk of fracture. The pathogenesis of fracture is multifactorial with contributions from both traditional and HIV-specific risk factors. Significant bone loss occurs on initiation of antiretroviral therapy but stabilizes on long-term therapy. Fracture risk assessment should be performed in HIV-infected individuals and bone mineral density measured when indicated. Lifestyle measures to optimize bone health should be advised and, in individuals at high risk of fracture, treatment with bisphosphonates considered.

Switching antiretroviral regimes for the treatment of HIV: safety implications

INTRODUCTION

There are multiple reasons to switch from a virologically successful antiretroviral regimen. Some of them are related to toxicity. Lately, combination antiretroviral treatment (cART) switches have often been related to drug-drug interactions which may also eventually entail safety issues as well.

AREAS COVERED

The purpose of this review is to analyze causes of switching between virologically successful cART regimes related to safety issues. The most relevant papers were selected and summarized.

EXPERT OPINION

Switching cART has been a popular strategy to address safety issues throughout the antiretroviral era. The myriad of switching studies have paralleled the study and release into clinical practice of new antiretroviral drugs with different and often improved safety profiles. Most of them have been successful in improving antiretroviral toxicity while keeping HIV replication under control. However, it should be taken into account that, whenever a new drug is given, there is a possibility of new drug-related toxicity. Notwithstanding that, an increase in cART switching is foreseen, given the fact that we have a wide antiretroviral drug armamentarium and that people living with HIV are ageing and thus more prone to developing age-related co-morbidities whose therapies may entail new interactions and eventually new toxicities.

Antiretroviral Therapy for Prevention of Human Immunodeficiency Virus Infection

Human immunodeficiency virus (HIV) infection is considered a chronic medical condition. Several new drugs are available, including fixed-dose combination tablets, that have greatly simplified combination antiretroviral therapy (ART) regimens to treat HIV, while increasing the life-expectancy of infected individuals. In the last decade, multiple well-regarded studies have established the benefits of using ART in high-risk, HIV-negative persons to prevent HIV acquisition. The primary care provider must not only understand commonly encountered issues pertaining to ART, such as toxicities and drug interactions, but also needs to be aware of using ART for HIV prevention.

A Single-dose Zoledronic Acid Infusion Prevents Antiretroviral Therapy-induced Bone Loss in Treatment-naive HIV-infected Patients: A Phase IIb Trial

BACKGROUND

Human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) are associated with bone loss leading to increased fracture rate among HIV-infected individuals. ART-induced bone loss is most intense within the first 48 weeks of therapy, providing a window for prophylaxis with long-acting antiresorptives.

METHODS

In a phase 2, double-blind, placebo-controlled trial, we randomized 63 nonosteoporotic, ART-naive adults with HIV initiating ART with atazanavir/ritonavir + tenofovir/emtricitabine to a single zoledronic acid (ZOL) infusion (5 mg) vs placebo to determine the efficacy of ZOL in mitigating ART-induced bone loss. Plasma bone turnover markers and bone mineral density (BMD) were performed at weeks 0, 12, 24, and 48 weeks. Primary outcome was change in C-terminal telopeptide of collagen at 24 weeks. Repeated-measures analyses using mixed linear models were used to estimate and compare study endpoints.

RESULTS

The ZOL arm had a 65% reduction in bone resorption relative to the placebo arm at 24 weeks (0.117 ng/mL vs 0.338 ng/mL; P < .001). This effect of ZOL occurred as early as 12 weeks (73% reduction; P < .001) and persisted through week 48 (57% reduction; P < .001). The ZOL arm had an 8% higher lumbar spine BMD at 12 weeks relative to the placebo arm (P = .003), and remained 11% higher at 24 and 48 weeks. Similar trends were observed in the hip and femoral neck.

CONCLUSIONS

A single dose of ZOL administered at ART initiation prevented ART-induced bone loss through the first 48 weeks of ART, the period when ART-induced bone loss is most pronounced. Validation of these results in larger multicenter randomized clinical trials is warranted.

CLINICAL TRIALS REGISTRATION

NCT01228318.

The protease inhibitors and HIV-associated bone loss

PURPOSE OF REVIEW

HIV infection is an established risk factor for osteoporosis and bone fracture. Combination antiretroviral therapy (cART) increases bone resorption leading to an additional 2-6% bone mineral density (BMD) loss within the first 1-2 years of therapy. Although tenofovir disoproxil fumarate is often blamed for antiretroviral drug-associated bone loss, evidence abounds to suggest that other agents, including the protease inhibitors (PIs), have adverse bone effects. In the current review, we examine bone loss associated with protease inhibitor use, describing the relative magnitude of bone loss reported for individual protease inhibitors. We also review the potential mechanisms associated with protease inhibitor-induced bone loss.

RECENT FINDINGS

As a class, protease inhibitors contribute to a greater degree of bone loss than other anchor drugs. HIV disease reversal and the associated immune reconstitution following cART initiation play an important role in protease inhibitor-mediated bone loss in addition to plausible direct effects of protease inhibitors on bone cells.

SUMMARY

Protease inhibitors remain an important component of cART despite their adverse effects on bone. A better understanding of factors that drive HIV/cART-induced bone loss is needed to stem the rising rate of fracture in the HIV-infected population.

Improvement of BMD after Switching from Lopinavir/R Plus Two Nucleos(T)ide Reverse Transcriptase Inhibitors to Lopinavir/R Plus Lamivudine: OLE-LIP Substudy

OBJECTIVE

To compare 48-week changes in bone mineral density (BMD) and body fat distribution between patients continuing lopinavir/ritonavir and two NRTIs and those switching to lopinavir/ritonavir and lamivudine.

METHODS

Substudy of a randomized, open-label, multicenter OLE study was carried out. Adult HIV-infected patients with <50 copies/mL for ≥6 months were randomized (1:1) to continue lopinavir/ritonavir and two NRTIs or switching to lopinavir/ritonavir and lamivudine. Dual-energy X-ray absorptiometry (DXA) was performed at baseline and after 48 weeks to measure bone composition and body fat distribution in both the groups.

RESULTS

Forty-one patients (dual-therapy, n = 23; triple-therapy, n = 18) of 239, who received at least one dose of study medication, completed the study: median age, 42 years, 71% male, 73% Caucasian. At week 48, total BMD increased by 1.04% (95% CI, 0.06 to 2.01%) among patients switching to dual-therapy, whereas no significant changes occurred in patients maintaining triple-therapy. Dual-therapy and older age were independently associated with total BMD increase. Among patients discontinuing tenofovir-DF, a significant increase was seen in total BMD (1.43; 95% CI, -0.04 to 2.91) and total hip (1.33%; 95% CI, 0.44 to 2.22%). A non-statistically significant decrease in femoral and spinal BMD was observed in patients who discontinued abacavir and in those continuing triple-therapy. Regarding fat distribution, no significant changes were seen in both the treatment groups.

DISCUSSION

BMD increased following switching to lopinavir/ritonavir plus lamivudine in HIV-infected patients on suppressive triple-therapy with lopinavir/ritonavir and two NRTIs including tenofovir-DF.

Transforming growth factor-β1-mediated cardiac fibrosis: potential role in HIV and HIV/antiretroviral therapy-linked cardiovascular disease

HIV infection elevates the incidence of cardiovascular disease (CVD) independent of traditional risk factors. Autopsy series document cardiac inflammation and endomyocardial fibrosis in the HIV+ treatment naïve, and gadolinium enhancement magnetic resonance imaging has identified prominent myocardial fibrosis in the majority of HIV+ individuals despite use of suppressive antiretroviral therapies (ART). The extent of such disease may correlate with specific ART regimens. For example, HIV-infected patients receiving ritonavir (RTV)-boosted protease inhibitors have the highest prevalence of CVD, and RTV-exposed rodents exhibit cardiac dysfunction coupled with cardiac and vascular fibrosis, independent of RTV-mediated lipid alterations. We recently showed that platelet transforming growth factor (TGF)-β1 is a key contributor to cardiac fibrosis in murine models. We hypothesize that in the HIV+/ART naïve, cardiac fibrosis is a consequence of proinflammatory cytokine and/or ART-linked platelet activation with release of TGF-β1. Resultant TGF-β1/Smad signaling would promote collagen synthesis and organ fibrosis. We document these changes in a pilot immunohistochemical evaluation of cardiac tissue from two ART-naive pediatric AIDS patients. In terms of ART, we showed that RTV inhibits immunoproteasome degradation of TRAF6, a nuclear adapter signaling molecule critical to the regulation of proinflammatory cytokine signaling pathways involved in osteoclast differentiation and accelerated osteoporosis. We now present a model illustrating how RTV could similarly amplify TGF-β1 signaling in the promotion of cardiac fibrosis and accelerated CVD. Supportive clinical data correlate RTV use with elevation of NT-proBNP, a biomarker for CVD. We discuss potential interventions involving intrinsic modulators of inflammation and collagen degradation, including carbon monoxide-based therapeutics.

Perspectives on menopause and women with HIV

Since the implementation of effective combination antiretroviral therapy, HIV infection has been transformed from a life-threatening condition into a chronic disease. As people with HIV are living longer, aging and its associated manifestations have become key priorities as part of HIV care. For women with HIV, menopause is an important part of aging to consider. Women currently represent more than one half of HIV-positive individuals worldwide. Given the vast proportion of women living with HIV who are, and will be, transitioning through age-related life events, the interaction between HIV infection and menopause must be addressed by clinicians and researchers. Menopause is a major clinical event that is universally experienced by women, but affects each individual woman uniquely. This transitional time in women's lives has various clinical implications including physical and psychological symptoms, and accelerated development and progression of other age-related comorbidities, particularly cardiovascular disease, neurocognitive dysfunction, and bone mineral disease; all of which are potentially heightened by HIV or its treatment. Furthermore, within the context of HIV, there are the additional considerations of HIV acquisition and transmission risk, progression of infection, changes in antiretroviral pharmacokinetics, response, and toxicities. These menopausal manifestations and complications must be managed concurrently with HIV, while keeping in mind the potential influence of menopause on the prognosis of HIV infection itself. This results in additional complexity for clinicians caring for women living with HIV, and highlights the shifting paradigm in HIV care that must accompany this aging and evolving population.

Epidemiology of Vertebral Fractures

Vertebral fractures are one of the most common fractures associated with skeletal fragility and can cause as much morbidity as hip fractures. However, the epidemiology of vertebral fractures differs from that of osteoporotic fractures at other skeletal sites in important ways, largely because only one quarter to one-third of vertebral fractures are recognized clinically at the time of their occurrence and otherwise require lateral spine imaging to be recognized. This article first reviews the prevalence and incidence of clinical and radiographic vertebral fractures in populations across the globe and secular trends in the incidence of vertebral fracture over time. Next, associations of vertebral fractures with measures of bone mineral density and bone microarchitecture are reviewed followed by associations of vertebral fracture with various textural measures of trabecular bone, including trabecular bone score. Finally, the article reviews clinical risk factors for vertebral fracture and the association of vertebral fractures with morbidity, mortality, and other subsequent adverse health outcomes.

Greater change in bone turnover markers for efavirenz/emtricitabine/tenofovir disoproxil fumarate versus dolutegravir + abacavir/lamivudine in antiretroviral therapy-naive adults over 144 weeks

OBJECTIVE

Antiretroviral therapy initiation has been linked to bone mineral density and bone biomarker changes. We assessed long-term bone turnover biomarker effects over 144 weeks in patients initiating dolutegravir (DTG) + abacavir/lamivudine (ABC/3TC) versus efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF).

METHODS

Patients randomized in SINGLE received DTG (50 mg once daily) + ABC/3TC or fixed-dose combination EFV/FTC/TDF. We evaluated vitamin D serum levels and bone turnover markers (BTMs), including type 1 collagen cross-linked C-telopeptide (CTx), osteocalcin, bone-specific alkaline phosphatase (BSAP), and procollagen type 1 N-terminal propeptide (P1NP), at baseline and weeks 48, 96, and 144.

RESULTS

Among the 833 enrolled patients (68% white, 85% men), baseline median age was 35 years (range 18-85), median CD4 was 338 cells/μl, and median BMI was 24 kg/m. Fifty-three percent of patients smoked, and 6% reported baseline vitamin D use, with no meaningful differences between groups. Relative to baseline, CTx, osteocalcin, BSAP, and P1NP increased; vitamin D decreased in both groups at weeks 48, 96, and 144. Changes from baseline typically peaked at weeks 48 or 96 and for the four analytes, excluding vitamin D, with the EFV/FTC/TDF group having significantly greater changes from baseline at all time points.

CONCLUSION

DTG + ABC/3TC in antiretroviral therapy-naive patients resulted in significantly lower increases in BTMs (CTx, osteocalcin, BSAP, P1NP) compared with EFV/FTC/TDF over 144 weeks. The observed changes are consistent with results from other smaller, randomized trials. These differences in BTMs likely correlate with changes in bone mineral density over time.

Bone Disease in HIV: Recommendations for Screening and Management in the Older Patient

Availability of potent antiretroviral therapy (ART) has resulted in markedly improved survival for people with human immunodeficiency virus (HIV) infection, as well as an aging HIV population. Increasing morbidity from age-related conditions has resulted in the need to understand the complex roles HIV and its treatment play in the pathogenesis of these conditions. Bone disease and fragility fractures are conditions that occur more frequently in HIV. It is therefore recommended that risk assessment for fragility fracture using the Fracture Risk Assessment Tool (FRAX(®)) algorithm, and low bone mass by dual energy X-ray absorptiometry (DXA) scan, be performed in all patients with HIV infection over the age of 50 years and in those with a history of fragility fracture, and should be repeated every 2-3 years. Because many HIV experts believe that HIV infection and its treatment is a secondary cause of osteoporosis, it should be included as such in the FRAX(®) assessment tool. Management of osteoporosis in HIV infection should follow the same guidelines as that in the general population. Attention to lifestyle factors, including vitamin D replacement, should be emphasized. Whether cessation of tenofovir- or protease inhibitor-based ART regimens should be considered prior to bisphosphonate treatment is currently unknown and should only occur in patients with active alternative ART regimens. The use of bisphosphonates has been shown to be safe and effective in HIV patients, and while there is limited data on second-line osteoporosis regimens, there is no reason to suggest they would not be effective in people with HIV.

Increased Fracture Incidence in Middle-Aged HIV-Infected and HIV-Uninfected Women: Updated Results From the Women's Interagency HIV Study

BACKGROUND

We previously reported that fracture incidence rates did not differ by HIV status among predominantly premenopausal Women's Interagency HIV Study participants. We now conduct a follow-up study with 5 additional observation years to further characterize fracture risk associated with HIV infection in women as they age.

METHODS

We measured time to first new fracture at any site in 2375 (1713 HIV-infected and 662 HIV-uninfected) Women's Interagency HIV Study participants, with median 10-year follow-up. Fractures were self-reported semiannually. Proportional hazards models assessed predictors of incident fracture.

RESULTS

At index visit, HIV-infected women were older [median age of 40 years (IQR: 34-46) vs. 35 (27-43), P < 0.0001] and more likely to be postmenopausal, hepatitis C virus infected, and weigh less than HIV-uninfected women. Among HIV-infected women, mean CD4 count was 480 cells per microliter and 63% were taking highly active antiretroviral therapy. Unadjusted incidence rates of any fracture were higher in HIV-infected than in HIV-uninfected women [2.19/100 person-years (py) vs. 1.54/100 py, P = 0.002]. In multivariate models, HIV status, older age, white (vs. black) race, prior fracture, history of cocaine use, and history of injection drug use were significant predictors of incident fracture. Among HIV-infected women, age, white race, prior fracture, smoking, and prior AIDS were predictors of new fracture.

CONCLUSIONS

Middle-aged HIV-infected women had a higher adjusted fracture rate than HIV-uninfected women. Cocaine use and injection drug use were also associated with a greater risk of incident fracture. Further research is needed to understand whether the risk of fracture associated with cocaine use relates to increased rate of falls or direct effects on bone metabolism.

Increased risk of hip fracture associated with dually treated HIV/hepatitis B virus coinfection

HIV and hepatitis B virus (HBV) infections are each associated with reduced bone mineral density, but it is unclear whether HIV/HBV coinfection is associated with an increased risk of fracture. We determined whether dually treated HIV/HBV patients had a higher incidence of hip fracture compared to treated HBV-monoinfected, antiretroviral therapy (ART)-treated HIV-monoinfected and HIV/HBV-uninfected patients. We conducted a cohort study among 4156 dually treated HIV/HBV-coinfected, 2053 treated HBV-monoinfected, 96,253 ART-treated HIV-monoinfected, and 746,794 randomly sampled uninfected persons within the US Medicaid populations of California, Florida, New York, Ohio and Pennsylvania (1999-2007). Coinfected patients were matched on propensity score to persons in each comparator cohort. Weighted survival models accounting for competing risks were used to estimate cumulative incidences and hazard ratios (HRs) with 95% confidence intervals (CIs) of incident hip fracture for dually treated coinfected patients compared to (i) HBV-monoinfected receiving nucleos(t)ide analogue or interferon alfa therapy, (ii) HIV-monoinfected on ART and (iii) uninfected persons. Dually treated coinfected patients had a higher cumulative incidence of hip fracture compared to ART-treated HIV-monoinfected (at 5 years: 1.70% vs 1.24%; adjusted HR, 1.37 [95% CI, 1.03-1.83]) and uninfected (at 5 years: 1.64% vs 1.22%; adjusted HR, 1.35 [95% CI, 1.03-1.84]) persons. The cumulative incidence of hip fracture was higher among coinfected than treated HBV-monoinfected patients (at 5 years: 0.70% vs 0.27%), but this difference was not statistically significant in competing risk analysis (adjusted HR, 2.62 [95% CI, 0.92-7.51]). Among Medicaid enrollees, the risk of hip fracture was higher among dually treated HIV/HBV-coinfected patients than ART-treated HIV-monoinfected and uninfected persons.

Bone mineral density and inflammatory and bone biomarkers after darunavir-ritonavir combined with either raltegravir or tenofovir-emtricitabine in antiretroviral-naive adults with HIV-1: a substudy of the NEAT001/ANRS143 randomised trial

BACKGROUND

Osteopenia, osteoporosis, and low bone mineral density are frequent in patients with HIV. We assessed the 96 week loss of bone mineral density associated with a nucleoside or nucleotide reverse transcriptase inhibitor (NtRTI)-sparing regimen.

METHODS

Antiretroviral-naive adults with HIV were enrolled in 78 clinical sites in 15 European countries into a randomised (1:1), open-label, non-inferiority trial (NEAT001/ANRS143) assessing the efficacy and safety of darunavir (800 mg once per day) and ritonavir (100 mg once per day) plus either raltegravir (400 mg twice per day; NtRTI-sparing regimen) or tenofovir (245 mg once per day) and emtricitabine (200 mg once per day; standard regimen). For this bone-health substudy, 20 of the original sites in six countries participated, and any patient enrolled at one of these sites who met the following criteria was eligible: plasma viral loads greater than 1000 HIV RNA copies per mL and CD4 cell counts of fewer than 500 cells per μL, except in those with symptomatic HIV infection. Exclusion criteria included treatment for malignant disease, testing positive for hepatitis B virus surface antigen, pregnancy, creatinine clearance less than 60 mL per min, treatment for osteoporosis, systemic steroids, or oestrogen-replacement therapy. The two primary endpoints were the mean percentage changes in lumbar spine and total hip bone mineral density at week 48, assessed by dual energy x-ray absorptiometry (DXA) scans. We did the analysis with an intention-to-treat-exposed approach with antiretroviral modifications ignored. The parent trial is registered with ClinicalTrials.gov, number NCT01066962, and is closed to new participants.

FINDINGS

Between Aug 2, 2010, and April 18, 2011, we recruited 146 patients to the substudy, 70 assigned to the NtRTI-sparing regimen and 76 to the standard regimen. DXA data were available for 129, 121 and 107 patients at baseline, 48 and 96 weeks respectively. At week 48, the mean percentage loss in bone mineral density in the lumbar spine was greater in the standard group than in the NtRTI-sparing group (mean percentage change -2.49% vs -1.00%, mean percentage difference -1.49, 95% CI -2.94 to -0.04; p=0.046). Total hip bone mineral density loss was similarly greater at week 48 in the standard group than in the NtRTI-sparing group (mean percentage change -3.30% vs -0.73%; mean percentage difference -2.57, 95% CI -3.75 to -1.35; p<0.0001). Seven new fractures occurred during the trial (two in the NtRTI-sparing group and five in the standard group).

INTERPRETATION

A raltegravir-based regimen was associated with significantly less loss of bone mineral density than a standard regimen containing tenofovir disoproxil fumarate, and might be a treatment option for patients at high risk of osteopenia or osteoporosis who are not suitable for NtRTIs such as abacavir or tenofovir alafenamide.

FUNDING

The European Union Sixth Framework Programme, Inserm-ANRS, Ministerio de Sanidad y Asuntos Sociales de España, Gilead Sciences, Janssen Pharmaceuticals, and Merck Laboratories.

Heel quantitative ultrasound in HIV-infected patients: a cross-sectional study

PURPOSE

HIV infection has been associated with increased risk of osteoporosis and fragility fractures. Dual-energy X-ray absorptiometry (DXA) is the reference standard to assess bone mineral density (BMD); however, it is not easily accessible in several settings. Heel Quantitative ultrasound (QUS) is a radiation-free, easy-to-perform technique, which may help reducing the need for DXA.

METHODS

In this cross-sectional study, we used heel QUS (Hologic Sahara(®)) to assess bone status in a cohort of HIV-infected patients. A QUS stiffness index (QUI) threshold >83 was used to identify patients with a low likelihood of osteoporosis. Moreover, we compared QUS results with those of 36 sex- and age-matched HIV-negative controls.

RESULTS

244 HIV-positive patients were enrolled. Median heel QUI value was 83 (73-96) vs. 93 (IQR 84-104) in the control group (p = 0.04). 110 patients (45 %) had a QUI value ≤83. Risk factors for low QUI values were age (OR 1.04 per year, 95 % CI 1.01-1.07, p = 0.004), current use of protease inhibitors (OR 1.85, CI 1.03-3.35, p = 0.039), current use of tenofovir (OR 2.28, CI 1.22-4.27, p = 0.009) and the number of risk factors for secondary osteoporosis (OR 1.46, CI 1.09-1.95, p = 0.01). Of note, QUI values were significantly correlated with FRAX score (r = -0.22, p = 0.004). According to EACS guidelines, 45 % of patients had risk factors for osteoporosis which make them eligible for DXA. By using QUS, we may avoid DXA in around half of them.

CONCLUSIONS

As HIV-positive patients are living longer, the prevalence of osteoporosis is expected to increase over time. Appropriate screening, prevention and treatment are crucial to preserve bone health in this population. The use of screening techniques, such as heel QUS, may help reducing the need for DXA. Further studies are needed to define the diagnostic accuracy of this promising technique in the setting of HIV.

Dental age estimation in Brazilian HIV children using Willems' method

The notification of the Human Immunodeficiency Virus (HIV) in Brazilian children was first reported in 1984. Since that time more than 21 thousand children became infected. Approximately 99.6% of the children aged less than 13 years old are vertically infected. In this context, most of the children are abandoned after birth, or lose their relatives in a near future, growing with uncertain identification. The present study aims to estimate the dental age of Brazilian HIV patients in face of healthy patients paired by age and gender. The sample consisted of 160 panoramic radiographs of male (n: 80) and female (n: 80) patients aged between 4 and 15 years (mean age: 8.88 years), divided into HIV (n: 80) and control (n: 80) groups. The sample was analyzed by three trained examiners, using Willems' method, 2001. Intraclass Correlation Coefficient (ICC) was applied to test intra- and inter-examiner agreement, and Student paired t-test was used to determine the age association between HIV and control groups. Intra-examiner (ICC: from 0.993 to 0.997) and inter-examiner (ICC: from 0.991 to 0.995) agreement tests indicated high reproducibility of the method between the examiners (P<0.01). Willems' method revealed discrete statistical overestimation in HIV (2.86 months; P=0.019) and control (1.90 months; P=0.039) groups. However, stratified analysis by gender indicate that overestimation were only concentrated in male HIV (3.85 months; P=0.001) and control (2.86 months; P=0.022) patients. The significant statistical differences are not clinically relevant once only few months of discrepancy are detected applying Willems' method in a Brazilian HIV sample, making this method highly recommended for dental age estimation of both HIV and healthy children with unknown age.

Clinically Indicated Corticosteroids Do Not Affect Bone Turnover During Immune Restoration of Severely Lymphopenic HIV-Infected Patients

Lymphopenia, corticosteroids, antiretroviral therapy (ART), and inflammation negatively impact bone turnover and decrease bone mineral density, but their combined effect has not been evaluated. We examined the association between corticosteroids on bone turnover markers in severely lymphopenic HIV-infected patients initiating ART. Levels of osteocalcin (bone formation marker) and C-terminal telopeptide (CTX; bone resorption marker) were measured at baseline, weeks 4, 12, and 48 of ART in individuals with severe lymphopenia and opportunistic infection (OI) who received (n=28) or did not receive corticosteroids (n=30) during the first year of ART, and in a control group with CD4 >200 (n=15). Wilcoxon tests were used to compare median values of variables between groups. Correlations between plasma interleukin (IL)-6 and tumor necrosis factor (TNF) levels with bone turnover marker levels were performed using Spearman's coefficient. Individuals given corticosteroids received a median of 21 days at a 35 mg prednisone-equivalent daily dose. Individuals with severe lymphopenia had lower osteocalcin levels at baseline and week 4 and higher CTX levels at ART initiation vs.

CONTROLS

Bone turnover markers did not differ in severely lymphopenic persons according to corticosteroid receipt. In those with severe lymphopenia, higher IL-6 was associated with higher CTX levels at ART initiation only. HIV-infected patients with severe lymphopenia and OI had lower levels of bone formation and higher levels of bone resorption than those initiating ART at higher CD4. Corticosteroid use, as prescribed during OI, was not associated with bone turnover. In contrast, higher markers of systemic inflammation prior to ART were associated with greater bone resorption.

Plasma Sclerostin in HIV-Infected Adults on Effective Antiretroviral Therapy

Sclerostin is linked to bone physiology and cardiovascular disease through the Wnt/β-catenin signaling pathway. The goal of this study was to determine if sclerostin is related to bone physiology and cardiovascular disease during antiretroviral treatment in HIV-infected persons. This was a cross-sectional analysis from study entry into the Stopping Atherosclerosis and Treating Unhealthy bone with RosuvastatiN in HIV (SATURN) trial, an ongoing randomized trial comparing rosuvastatin to placebo in HIV-infected adults on antiretroviral therapy. Plasma sclerostin was measured at study entry by ELISA from participants with available samples. Spearman correlation and multivariable linear regression were used to test relationships between sclerostin and bone density or bone turnover and cardiovascular disease. Among 139 HIV-infected participants (median age 46 years, CD4 lymphocyte count 614 cells/μl), the median plasma sclerostin level was 444.1 (IQR 330.3, 570.1) pg/ml. Correlations were detected between sclerostin and age (r=0.26), lumbar spine Z-score (r=0.31), RANKL (r=-0.21), carotid intima-media thickness (CIMT, r=0.19), and sVCAM-1 (r=0.27), p<0.05. No significant correlations were detected between sclerostin and current (r=0.006) or nadir CD4 count (r=0.11). While associations between sclerostin, lumbar spine Z-score, and sVCAM-1 were robust to covariate adjustment (p<0.01), association with CIMT was no longer significant (p=0.08). Our findings provide preliminary support for a relationship between sclerostin and bone mineral density in HIV-infected persons. The Wnt/β-catenin pathway should be investigated as a potential mechanism for loss of bone mineral density in treated HIV infection.

Vitamin D and Calcium Attenuate Bone Loss With Antiretroviral Therapy Initiation: A Randomized Trial

BACKGROUND

Antiretroviral therapy initiation for HIV-1 infection is associated with 2% to 6% loss of bone mineral density (BMD).

OBJECTIVE

To evaluate the effect of vitamin D3 plus calcium supplementation on bone loss associated with antiretroviral therapy initiation.

DESIGN

48-week prospective, randomized, double-blind, placebo-controlled study. (ClinicalTrials.gov: NCT01403051).

SETTING

39 AIDS Clinical Trials Group units.

PATIENTS

Adults with antiretroviral therapy-naive HIV.

MEASUREMENTS

BMD by dual-energy x-ray absorptiometry, 25-hydroxyvitamin D levels, and other laboratory assessments.

RESULTS

165 eligible patients were randomly assigned (79 received vitamin D3 plus calcium and 86 received placebo). The study groups were well-balanced at baseline: 90% were men, 33% were non-Hispanic black, and the median CD4 count was 0.341 × 109 cells/L. At 48 weeks, the percentage of decline in total hip BMD was smaller in the vitamin D3 plus calcium group than in the placebo group: Medians were -1.36% (interquartile range [IQR], -3.43% to 0.50%) and -3.22% (IQR, -5.56% to -0.88%), respectively (P = 0.004). Similar results were seen at the lumbar spine. At 48 weeks, 90% of patients achieved HIV-1 RNA levels less than 50 copies/mL. Levels of 25-hydroxyvitamin D3 increased with vitamin D3 plus calcium but not with placebo: Median change was 61.2 nmol/L (IQR, 36.4 to 94.3) versus 1.7 nmol/L (IQR, -13.2 to 10.7) (P < 0.001). Overall, 103 patients (62%) reported 1 or more adverse event, with similar distribution between groups; no cases of hypercalcemia and 1 case of nephrolithiasis were reported in the placebo group.

LIMITATION

No international sites were included, and follow-up was only 48 weeks.

CONCLUSION

Vitamin D3 plus calcium supplementation mitigates the BMD loss seen with initiation of efavirenz/emtricitabine/tenofovir disoproxil fumarate.

Less Bone Loss With Maraviroc- Versus Tenofovir-Containing Antiretroviral Therapy in the AIDS Clinical Trials Group A5303 Study

BACKGROUND

There is a need to prevent or minimize bone loss associated with antiretroviral treatment (ART) initiation. We compared maraviroc (MVC)- to tenofovir disoproxil fumarate (TDF)-containing ART.

METHODS

This was a double-blind, placebo-controlled trial. ART-naive subjects with human immunodeficiency virus type 1 RNA load (viral load [VL]) >1000 copies/mL and R5 tropism were randomized to MVC 150 mg or TDF 300 mg once daily (1:1), stratified by VL <100 000 or ≥100 000 copies/mL and age <30 or ≥30 years. All subjects received darunavir 800 mg, ritonavir 100 mg, and emtricitabine 200 mg daily. Dual-energy X-ray absorptiometry scanning was done at baseline and week 48. The primary endpoint was percentage change in total hip bone mineral density (BMD) from baseline to week 48 in the as-treated population.

RESULTS

We enrolled 262 subjects. A total of 259 subjects (130 MVC, 129 TDF) contributed to the analyses (91% male; median age, 33 years; 45% white, 30% black, 22% Hispanic). Baseline median VL was 4.5 log10 copies/mL and CD4 count was 390 cells/µL. The decline in hip BMD (n = 115 for MVC, n = 109 for TDF) at week 48 was less with MVC (median [Q1, Q3] of -1.51% [-2.93%, -0.11%] vs -2.40% [-4.30%, -1.32%] for TDF (P < .001). Lumbar spine BMD decline was also less with MVC (median -0.88% vs -2.35%; P < .001). Similar proportions of subjects in both arms achieved VL ≤50 copies/mL in as-treated and ITT analyses.

CONCLUSIONS

MVC was associated with less bone loss at the hip and lumbar spine compared with TDF. MVC may be an option to attenuate ART-associated bone loss.

CLINICAL TRIALS REGISTRATION

NCT01400412.

Tenofovir: What We Have Learnt After 7.5 Million Person-Years of Use

Tenofovir was licensed for use in patients with HIV in 2001 and since then has become a firmly established anti-retroviral in both guidelines and routine practice. Data have been presented from many pivotal studies—informing on its efficacy, use, and adverse features—and there are also over 7.5 million patient-years of experience to date. We explore the data on this nucleotide reverse transcriptase inhibitor in HIV presented since 2008—focusing on efficacy, side effects, and utility.

Raltegravir and Abacavir/Lamivudine in Japanese Treatment-Naïve and Treatment-Experienced Patients with HIV Infection: a 48-Week Retrospective Pilot Analysis

Abacavir/lamivudine (ABC/3TC) is a nucleoside reverse transcriptase inhibitor used for treating human immunodeficiency viral (HIV) infections. Hypersensitivity reactions such as skin eruptions caused by ABC are well-known, but rarely occur in Asians. Raltegravir (RAL) is an integrase strand transfer inhibitor, that is now increasingly, used for treating HIV infections because it has few adverse effects. This retrospective analysis assessed the efficacy and safety of combined ABC/3TC and RAL in both treatment-naïve and -experienced Japanese patients with HIV infections. In all 11 treatment-naïve patients (100%), virological suppression to undetectable level was achieved. Liver transaminases, renal function, and serum lipid profiles showed no exacerbations up to 48 weeks of treatment. In 12 patients who were switched from previous regimens to ABC/3TC and RAL, HIV viral load was undetectable in 11 patients (91.6%), but remained detectable in 1 patient with poor adherence. Major reasons for switching regimens to ABC/3TC and RAL were hyperlipidemia and nausea. After switching, these adverse effects improved, and no new adverse effects were observed. Despite the small number of participants in this study, the results support the combination of ABC/3TC and RAL as a possible treatment choice in Japanese individuals with HIV-infection.

Changes in Bone Mineral Density After Initiation of Antiretroviral Treatment With Tenofovir Disoproxil Fumarate/Emtricitabine Plus Atazanavir/Ritonavir, Darunavir/Ritonavir, or Raltegravir

BACKGROUND

Specific antiretroviral therapy (ART) medications and the severity of human immunodeficiency virus (HIV) disease before treatment contribute to bone mineral density (BMD) loss after ART initiation.

METHODS

We compared the percentage change in BMD over 96 weeks in 328 HIV-infected, treatment-naive individuals randomized equally to tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) plus atazanavir/ritonavir (ATV/r), darunavir/ritonavir (DRV/r), or raltegravir (RAL). We also determined whether baseline levels of inflammation markers and immune activation were independently associated with BMD loss.

RESULTS

At week 96, the mean percentage changes from baseline in spine and hip BMDs were similar in the protease inhibitor (PI) arms (spine: -4.0% in the ATV/r group vs -3.6% in the DRV/r [P = .42]; hip: -3.9% in the ATV/r group vs -3.4% in the DRV/r group [P = .36]) but were greater in the combined PI arms than in the RAL arm (spine: -3.8% vs -1.8% [P < .001]; hip: -3.7% vs -2.4% [P = .005]). In multivariable analyses, higher baseline concentrations of high-sensitivity C-reactive protein, interleukin 6, and soluble CD14 were associated with greater total hip BMD loss, whereas markers of CD4(+) T-cell senescence and exhaustion (CD4(+)CD28(-)CD57(+)PD1(+)) and CD4(+) T-cell activation (CD4(+)CD38(+)HLA-DR(+)) were associated with lumbar spine BMD loss.

CONCLUSIONS

BMD losses 96 weeks after ART initiation were similar in magnitude among patients receiving PIs, ATV/r, or DRV/r but lowest among those receiving RAL. Inflammation and immune activation/senescence before ART initiation independently predicted subsequent BMD loss.

Metabolic and renal adverse effects of antiretroviral therapy in HIV-infected children and adolescents

Worldwide, the benefits of combined antiretroviral (ARV) therapy in morbidity and mortality due to perinatally acquired human immunodeficiency virus infection are beyond question and outweigh the toxicity these drugs have been associated with in HIV-infected children and adolescents to date. In puberty, abnormal body fat distribution is stigmatizating and leads to low adherence to ARV treatment. The other metabolic comorbidities (mitochondrial toxicity, dyslipidemias, insulin resistance and low bone mineral density) and renal toxicity, albeit nonsymptomatic in most children, are increasingly being reported and potentially put this population at risk for early cardiovascular or cerebrovascular atherosclerotic disease, diabetes, pathologic fractures or premature renal failure in the third and fourth decades of life. Evidence from available studies is limited because of methodological limitations and also because of several HIV-unrelated factors influencing, to some degree, the development of these conditions. Current recommendations for the prevention, diagnosis, monitoring and treatment of metabolic and renal adverse effects in HIV-children and adolescents are based on adult studies, observational pediatric studies and experts' consensus. Healthy lifestyle habits (regarding diet, exercise and refraining from toxic substances) and wise use of ARV options are the only preventive tools for the majority of patients. Should abnormal findings arise, switches in one or more ARV drugs have proved useful. Specific therapies are also available for some of these comorbidities, although the experience in the pediatric age is still very scarce. We aim to summarize the epidemiological, clinical and therapeutic aspects of metabolic and renal adverse effects in vertically HIV-infected children and adolescents.

Differential skeletal impact of tenofovir disoproxil fumarate in young versus old HIV-infected adults

BACKGROUND

Lower peak bone mass in early adulthood predicts subsequent fragility fractures. Antiretroviral toxicity could contribute to young HIV-infected individuals not achieving adequate peak bone mass.

OBJECTIVE

To determine if tenofovir disoproxil fumarate's (TDF) effect on bone mineral density (BMD) differs by age.

METHODS

We examined BMD data at the lumbar spine and hip from AIDS Clinical Trials Group (ACTG) A5224s and ASSERT and randomized treatment-naive studies comparing TDF/emtricitabine versus abacavir/lamivudine (with efavirenz or atazanavir/ritonavir). In this post hoc analysis, we defined the TDF effect as the difference between mean 48-week BMD per cent changes for lumbar spine and hip in individuals randomized to TDF versus abacavir. We used multivariable linear regression to compare the TDF effect in individuals younger and older than 30 years. If TDF effect by age did not differ significantly between studies, we pooled study populations. Otherwise, analyses were conducted separately within each study population.

RESULTS

Among 652 subjects, 21% were below age 30 years. The relationship between age and TDF effect significantly differed between A5224s and ASSERT (P = 0.008 for lumbar spine; P = 0.007 for hip). In A5224s, there was more bone loss with TDF at lumbar spine and hip in subjects under 30 years old versus in older subjects ( - 4.5% vs - 1.4%; P = 0.045; - 4.3% vs - 1.6%; P = 0.026, respectively). There was no significant evidence for this age-associated TDF effect in ASSERT.

CONCLUSIONS

There was heterogeneity in the observed effect of TDF on bone density in young adults compared to older adults, suggesting that further investigation is required to understand the impact of age on BMD decline with TDF.

Retroviral proteases and their roles in virion maturation

Proteolytic processing of viral polyproteins is essential for retrovirus infectivity. Retroviral proteases (PR) become activated during or after assembly of the immature, non-infectious virion. They cleave viral polyproteins at specific sites, inducing major structural rearrangements termed maturation. Maturation converts retroviral enzymes into their functional form, transforms the immature shell into a metastable state primed for early replication events, and enhances viral entry competence. Not only cleavage at all PR recognition sites, but also an ordered sequence of cleavages is crucial. Proteolysis is tightly regulated, but the triggering mechanisms and kinetics and pathway of morphological transitions remain enigmatic. Here, we outline PR structures and substrate specificities focusing on HIV PR as a therapeutic target. We discuss design and clinical success of HIV PR inhibitors, as well as resistance development towards these drugs. Finally, we summarize data elucidating the role of proteolysis in maturation and highlight unsolved questions regarding retroviral maturation.

Increased bone resorption during tenofovir plus lopinavir/ritonavir therapy in Chinese individuals with HIV

We sought to evaluate the effects of antiretroviral therapy on skeletal metabolism in Chinese individuals with human immunodeficiency virus. Patients switched to tenofovir/lamivudine + lopinavir/ritonavir after treatment failure had an increase in bone resorption marker levels by nearly 60%, which is greater than the magnitude previously described in non-Chinese populations.

INTRODUCTION

Few studies have evaluated the effects of antiretroviral therapy on skeletal metabolism in Asian populations infected with human immunodeficiency virus (HIV).

METHODS

We performed a secondary analysis of bone turnover markers (BTM) at baseline and 2 years in stored plasma samples collected from 2/2009 to 1/2013 as part of a multi-center trial. Two groups were compared: (1) treatment-naïve patients initiated on zidovudine (AZT)/lamivudine (3TC) plus nevirapine (NVP) and (2) patients who failed first-line therapy and were switched to tenofovir (TDF)/3TC plus lopinavir/ritonavir (LPVr). Tests included the bone resorption marker, C-terminal cross-linking telopeptide of type-1 collagen (CTX), and the bone formation marker procollagen type 1 N-terminal propeptide (P1NP).

RESULTS

In the TDF/3TC + LPVr group, samples were available from 59 patients at baseline and 56 patients at 2 years. Of these, 36 patients had samples available from both time points. In the AZT/3TC + NVP group, plasma samples were analyzed from 82 participants at baseline and of those, 61 had samples at 2 years. Median change over 2 years was greater in the TDF/3TC + LPVr group for both CTX (+0.24 ng/mL, interquartile ranges (IQR) 0.10-0.43 vs. +0.09 ng/mL, IQR -0.03 to 0.18, p = 0.001) and P1NP (+25.5 ng/mL, IQR 2.4-51.3 vs. +7.11 ng/mL, IQR -4.3 to 21.6, p = 0.012). Differences remained after adjusting for potential confounders in the multivariable analysis.

CONCLUSIONS

Switching to TDF/3TC + LPVr after treatment failure resulted in greater increases in BTMs than initiation with AZT/3TC + NVP in Chinese patients with HIV. Following this change, bone resorption marker levels increased by nearly 60 %, which is greater than the 25-35% increase from baseline described previously in non-Chinese populations. Further studies are warranted to elucidate these findings.

Changes in bone mineral density after 96 weeks of treatment with atazanavir/ritonavir or lopinavir/ritonavir plus tenofovir DF/emtricitabine in treatment-naive patients with HIV-1 infection: the CASTLE body composition substudy

: Antiretroviral therapy initiation is associated with declines in bone mineral density (BMD), which seem greatest with tenofovir disoproxil fumarate (DF)-containing regimens. Data comparing protease inhibitors are limited. This CASTLE substudy compared paired baseline with week 96 BMD in patients initiating tenofovir DF/emtricitabine plus atazanavir/ritonavir (n = 106) vs lopinavir/ritonavir (n = 70). In both groups, week 96 BMD declined significantly in arm, leg, trunk, and total body regions. Atazanavir/ritonavir was associated with smaller 96-week trunk and total body BMD declines compared with lopinavir/ritonavir [multivariate-adjusted least squares mean difference +2.00% (95% confidence interval: 0.52 to 3.45; P = 0.008) and +1.24% (95% confidence interval: 0.13 to 2.35; P = 0.029), respectively]. In addition, low baseline CD4 cell count (<50 cells per microliter) and increasing age were associated with larger declines in BMD.

Bone alterations associated with HIV

HIV infection and initiation of antiretroviral therapy (ART) have been consistently associated with decreased bone mineral density (BMD), with growing evidence linking HIV to an increased risk of fracture. This is especially concerning with the expanding number of older persons living with HIV. Interestingly, recent data suggest that HIV-infected children and youth fail to achieve peak BMD, possibly increasing their lifetime risk of fracture. Elucidating the causes of the bone changes in HIV-positive persons is challenging because of the multifactorial nature of bone disease in HIV, including contribution of the virus, immunosuppression, ART toxicity, and traditional osteoporosis risk factors, such as age, lower weight, tobacco, and alcohol use. Thus, practitioners must recognize the risk of low BMD and fractures and appropriately screen patients for osteoporosis if risk factors exist. If fractures do occur or elevated fracture risk is detected through screening, treatment with bisphosphonate medications appears safe and effective in the HIV+population.

HIV infection and osteoporosis

In the past two decades, the life expectancy of people living with HIV infection has increased significantly, and osteoporosis has emerged as a significant comorbidity. In addition to traditional risk factors for fracture, specific factors related to HIV infection are also likely to contribute, including antiretroviral therapy. The heterogeneity of the HIV-infected population in terms of age and ethnicity presents many challenges to the prevention and management of bone disease, and further studies are required to establish optimal approaches to risk assessment and treatment.

Bone mineral density changes after 2 years of ARV treatment, compared to naive HIV-1-infected patients not on HAART

BACKGROUND

The prevalence of osteopenia and osteoporosis is increased in human immunodeficiency virus (HIV)-infected patients. The pathogenesis of this low bone mineral density (BMD) is multifactorial.

METHODS

We conducted a prospective study over a 2-year period of the BMD in non-treated ARV-naïve HIV-infected-males, in comparison to HIV-infected males commencing a first ARV treatment, and analyzed the evolution of bone turnover markers.

RESULTS

A total of 39 caucasian males (median age 38.6 years) were enrolled, including 10 who started ARV treatment (group 1), and 29 without indications for ARV therapy (group 2). In the latter group, 11 subjects commenced ARV during the study; therefore the remainder of their follow-up was within group 1, which finally consisted of 21 patients. At baseline, 9 patients (19.5%) had osteoporosis at least at 1 site, while 28 (61%) showed osteopenia. Lower BMD was correlated with tobacco use. Lumbar spine and total hip BMD significantly decreased in group 1 patients after 6 months of treatment, then stabilized (2.4% and 4% loss, respectively, at 24 months), while no significant change in BMD was observed in group 2 subjects. At baseline, one patient had an increased CTX (C-terminal cross-linking telopeptide of type 1 collagen) and all BSAP (bone-specific alkaline phosphatase) results were normal. During follow-up, both CTX and BSAP increased in group 1 patients, while they did not change in group 2.

CONCLUSION

Osteoporosis and osteopenia are frequent in HIV-infected males. After ARV initiation, BMD decreased, and bone turnover markers increased, even though the BMD remained stable in non-treated patients. These results underline the impact of HIV treatment on BMD and bone metabolism.

Outcomes in older versus younger patients over 96 weeks in HIV-1- infected patients treated with rilpivirine or efavirenz in ECHO and THRIVE

Objectives:

Increasing life expectancy of HIV-1–infected patients raises interest in how trial results apply to older patients. This post-hoc analysis evaluated potential differences in efficacy and safety in older (≥50 years) versus younger (<50 years) patients in the ECHO and THRIVE trials over 96 weeks.

Methods:

HIV-infected, treatment-naÏve adults were randomized to receive rilpivirine (RPV) or efavirenz (EFV), plus a background regimen. Virologic response rates (FDA snapshot analysis; HIV-1 RNA <50 copies/mL) were assessed at Week 96. Total-body bone mineral density was evaluated at baseline and Week 96 by dual-energy X-ray absorptiometry scans. Serum concentrations of 25-hydroxy vitamin D (ECHO trial only) were also measured at baseline, Week 24 and Week 48.

Results:

1368 patients were treated. At Week 96, virologic response rates were similar between older (77%) and younger (76%) RPV-treated patients and numerically higher in older (84%) versus younger (76%) EFV-treated patients. No clinically relevant age-related differences were observed in immunologic responses. Small differences were noted in older versus younger patients in adverse events (higher rates of depression, insomnia, and rash in older EFV-treated patients), laboratory abnormalities (increased low-density lipoprotein cholesterol and hyperglycemia in older EFV-treated patients and increased amylase in older patients across treatments), bone mineral density (larger decreases in older patients across treatments), and progression to severe vitamin D deficiency (greater in older versus younger EFV-treated patients).

Conclusion:

Efficacy and safety outcomes were generally similar in older versus younger patients in the ECHO and THRIVE trials.

Microstructural alterations of trabecular and cortical bone in long-term HIV-infected elderly men on successful antiretroviral therapy

OBJECTIVE

Progress in antiretroviral therapy (ART) has resulted in an almost normal life expectancy for HIV-infected individuals, but an increased risk of fragility fractures has been identified. We investigated the influence of long-term HIV infection on successful ART on bone microstructure in elderly men.

DESIGN

A cross-sectional, case–control study.

METHODS

Dual-energy X-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HR-pQCT) were performed in 28 HIV-positive men between 60 and 70 years old on successful ART. Controls were 112 HIV-negative men matched for age 4 years and BMI (4 kg/ m²).

RESULTS

HIV-positive men (median CD4þ cell count, 589 cells/ml; BMI, 24.8 kg/m²) had a median duration of HIV infection of 18.2 years. Compared with HIV-negative men, they had a lower DXA-measured areal bone mineral density at total hip (3.2%, P¼0.050) and ultra-distal radius (8.4%, P¼0.001). At distal radius and tibia, we observed microstructural alterations with a lower total density (16%, P¼ 0.005 and 14.3%, P¼ 0.039), trabecular density (11.6%, P¼ 0.012 and 12.2%, P¼ 0.007) and cortical area (17.5%, P¼ 0.002 and 12.2%, P¼ 0.01). In addition, they had a lower trabecular number (P¼ 0.036), higher trabecular spacing (P¼ 0.027) and lower cortical thickness (19.9%; P¼ 0.008) at distal radius. beta-crosslaps (CTX) and vitamin D levels were higher than in controls. By multivariate analyses, HIV status, higher CTX levels, lower physical activity and estradiol levels were determinants of bone density and microstructure alterations.

CONCLUSION

HIV-infected elderly men on successful ART have trabecular and cortical bone microstructure alterations associated with higher bone resorption, despite adequate vitamin D supplementation.

Relative contribution of HIV infection, demographics and body mass index to bone mineral density

INTRODUCTION

Low bone mineral density (BMD) is common in HIV-positive patients, although the role played by HIV infection versus sociodemographic and metabolic factors remains unclear.

METHODS

Understanding the Pathology of Bone Disease in HIV-infected individuals (HIV UPBEAT) is a prospective cohort study, enrolled HIV-positive and HIV-negative participants from similar demographic backgrounds. Dual X-ray absorptiometry at femoral neck, total hip and lumbar spine and blood tests were performed. Associations between BMD and factors of interest were assessed using multivariable linear regression.

RESULTS

A total of 474 participants were recruited. Two hundred and ten were HIV-positive, of whom, 59% were male, 40% African and median (interquartile range) age was 39 (33, 46) years. HIV acquisition risks were heterosexual sex (46.9%), homosexual sex (25.4%) and intravenous drug use (18.7%). Of the HIV-negative participants, 44% were male, 25% were African and median (interquartile range) age was 42 (34-49) years. HIV infection was independently associated with a 0.062 (P < 0.0001), 0.078 (P < 0.0001) and 0.060 g/cm (P =  0.0002) lower BMD at femoral neck, total hip and lumbar spine, respectively, after adjustment for demographic/ lifestyle factors and BMI. After further adjustment for bone biomarkers, HIV remained independently associated with reduced BMD at each site, although effect sizes were reduced. The HIV-positive group had significantly higher bone turnover (all between-group P < 0.0001). Treatment variables and cumulative exposure to antiretroviral therapy were not associated with lower BMD at femoral neck or total hip, but acquisition of HIV infection via intravenous drug use and longer time since HIV diagnosis were independently associated with lower lumbar spine BMD.

DISCUSSION

HIV is independently associated with lower BMD, and its effect is likely mediated, in part, by alterations in bone metabolism.