HIV and fracture: Risk, assessment and intervention

OBJECTIVES

With management of comorbidity in people living with HIV (PLWH) a key component of clinical care, early loss of bone integrity and clinical fracture are recognized as important issues. This review aims to describe the epidemiology of fracture in PLWH, as well as summarizing the relative balance of factors that contribute to fracture. We also aim to describe fracture risk assessment and interventional strategies to modify the risk of fracture in this population.

RESULTS

Data from recent meta-analyses show that PLWH have significantly more fractures than the general population, with men and injecting drug users at higher risk. Modifiable factors that contribute to fracture risk in this cohort include body mass index (BMI), drug use, concurrent medications, frailty, and hepatitis C virus infection. Relating to antiretroviral therapy, current or ever tenofovir exposure has been identified as predictive of fracture but not cumulative use, and a potentially modest protective effect of efavirenz has been observed. Fracture Risk Assessment Tool scores underestimate fracture risk in PLWH with improved accuracy when HIV is considered a cause of secondary osteoporosis and bone mineral density (BMD) included.

CONCLUSION

Early consideration of risk, prompting evaluation of modifiable risk factors, frailty and falls risk with bone density imaging and prompt intervention may avert fracture in PLWH. Guidance on screening and lifestyle modification is available in international guidelines. Bisphosphonates are safe and effective in PLWH, with limited data for other agents.

Bone Quality in Relation to HIV and Antiretroviral Drugs

PURPOSE OF REVIEW

People living with HIV (PLWH) are at an increased risk for osteoporosis, a disease defined by the loss of bone mineral density (BMD) and deterioration of bone quality, both of which independently contribute to an increased risk of skeletal fractures. While there is an emerging body of literature focusing on the factors that contribute to BMD loss in PLWH, the contribution of these factors to bone quality changes are less understood. The current review summarizes and critically reviews the data describing the effects of HIV, HIV disease-related factors, and antiretroviral drugs (ARVs) on bone quality.

RECENT FINDINGS

The increased availability of high-resolution peripheral quantitative computed tomography has confirmed that both HIV infection and ARVs negatively affect bone architecture. There is considerably less data on their effects on bone remodeling or the composition of bone matrix. Whether changes in bone quality independently predict fracture risk, as seen in HIV-uninfected populations, is largely unknown. The available data suggests that bone quality deterioration occurs in PLWH. Future studies are needed to define which factors, viral or ARVs, contribute to loss of bone quality and which bone quality factors are most associated with increased fracture risk.

Sirtuins as Interesting Players in the Course of HIV Infection and Comorbidities

The sirtuins (SIRTs) are a family of enzymes from the group of NAD⁺-dependent deacetylases. Through the reaction of splitting the acetyl group of various transcription factors and histones they regulate many processes in the organism. The activity of sirtuins is linked to metabolic control, oxidative stress, inflammation and apoptosis, and they also affect the course of viral infections. For this reason, they may participate in the pathogenesis and development of many diseases, but little is known about their role in the course of human immunodeficiency virus (HIV) infection, which is the subject of this review. In the course of HIV infection, comorbidities such as: neurodegenerative disorders, obesity, insulin resistance and diabetes, lipid disorders and cardiovascular diseases, renal and bone diseases developed more frequently and faster compared to the general population. The role of sirtuins in the development of accompanying diseases in the course of HIV infection may also be interesting. There is still a lack of detailed information on this subject. The role of sirtuins, especially SIRT1, SIRT3, SIRT6, are indicated to be of great importance in the course of HIV infection and the development of the abovementioned comorbidities.

Bone deleterious effects of different nrtis in treatment-naïve HIV patients after 12 and 48 weeks of treatment

Background

Bone alterations have been observed in the course of HIV infection, characterized by a marked decrease in bone mineral density (BMD) and an increase in the frequency of fractures as a result of fragility. We aim to evaluate early changes in bone metabolic profile and the possible association with tenofovir and other nucleoside and nucleotide reverse transcriptase inhibitors (NRTIs) in treatment-naïve HIV patients.

Methods

We conducted a prospective study in naïve HIV-infected adults (under 50 years), separated into three groups according to NRTI therapy: tenofovir disoproxil fumarate (TDF); tenofovir alafenamide (TAF) and abacavir (ABC). BMD and epidemiological, immunological and metabolic bone parameters were evaluated. Bone markers were analyzed in plasma at baseline, 12 and 48 weeks after initiating treatment.

Results

Average age of patients was 34.8 years (± 9.6). 92.4% of them with CD4 count > 200 cel/μL. At week 12 after starting treatment, both TDF [increase in PN1P (31.7%, p = 0.004), TRAP (11.1%, p = 0.003), OPN (19.3%, p = 0.045) and OC (38.6%, p = 0.001); decrease in OPG (-23.4%, p = 0.003)] and TAF [increase in 42.6% for CTX (p = 0.011), 27.3% for OC (p = 0.001) and 21% for TRAP (p = 0.008); decrease in OPG (-28.8%, p = 0.049)] presented a deep resorption profile compared to ABC, these differences in bone molecular markers, a tendency to equalize at week 48, where no significant differences were observed. Patients treated with TDF showed the greatest decrease in Z-score in both lumbar spine (LS) and femoral neck (FN) at week 48 without statistically significant differences.

Conclusion

Treatment-naïve HIV patients have a high prevalence of low bone density. Treatment with TDF is associated with greater bone deterioration at 12 and 48 weeks. TAF seems to present similar early bone deterioration at 12 weeks which disappears at 48 weeks.

Higher comorbidity burden predicts worsening neurocognitive trajectories in people with HIV

BACKGROUND

Age-related comorbidities accumulate faster in people with HIV (PWH) than in those without (PWoH). We evaluated whether a validated multimorbidity scale, the Charlson Index, predicted neurocognitive trajectories in PWH.

METHODS

Scaled scores a comprehensive neuropsychological battery were averaged across all visits. Multilevel modeling examined between- and within-person predictors of global neurocognition. At the between-person level, averaged Charlson scores were examined as a predictor of neurocognitive change rate, covarying for HIV disease characteristics. Within-persons, visit-specific Charlson Index was used to predict fluctuations in global neurocognition at the same and next visit, covarying for disease measures.

RESULTS

Participants were 1195 PWH (mean baseline age 43·0; SD 9·7 years) followed for a mean of 7·1 years (range 0·5-20·5). At the between-person level, more rapid neurocognitive worsening correlated with higher (worse) average Charlson scores (standardized β -0·062, SE 0·015; p=0·001) and lower CD4 nadir (standardized β 0·055, SE 0·021; p=0·011), but not viral suppression or average CD4+ lymphocytes (ps > 0·05). At the within-person level, poorer visit-specific neurocognition was related to worse concurrent, but not preceding, Charlson scores (standardized β-0·046, SE 0·015; p = 0·003), detectable HIV viral load (standardized β0·018, SE 0·006; p = 0·001) and higher CD4+ (standardized β0·043, SE 0·009; p < 0·001).

CONCLUSION

The impact of comorbidities on neurocognitive decline exceeded that of HIV disease factors. Although correlative, the temporal relationships suggested that treatment of comorbidities might improve neurocognitive prognosis for PWH.

Association between Nonalcoholic Fatty Liver Disease and Bone Mineral Density in HIV-Infected Patients Receiving Long-term TDF-Based Antiretroviral Therapy

BACKGROUND

Tenofovir (TDF) has a detrimental effect on bone mineral density (BMD), while nonalcoholic fatty liver disease (NAFLD) is associated with a lower BMD.

OBJECTIVE

To help understand the mutual effects of NAFLD and TDF on BMD, this study was designed to explore the potential association between NAFLD and BMD in HIV-infected patients receiving long-term TDF-based antiretroviral therapy (ART).

METHODS

A total of 89 HIV-infected patients who received TDF-based ART for more than three years were enrolled in this cross-sectional study. We measured BMD using an ultrasonic bone density apparatus, and liver ultrasonography was performed to determine the severity of the fatty liver. The association of NAFLD with BMD was examined using multiple logistic regression analyses.

RESULTS

Patients with NAFLD showed a worse BMD status than those without NAFLD. The incidence rates of osteopenia (42.86% versus 25.93%) and osteoporosis (17.14% versus 3.70%) were significantly higher in HIV-infected patients with NAFLD than in those without NAFLD. After multivariate adjustment, the odds ratio (OR) for patients with NAFLD exhibiting a worse BMD status compared with those without NAFLD was 4.49 (95% confidence interval [CI] 1.42, 14.15).

CONCLUSION

Based on our results, NAFLD was significantly associated with a worse BMD status, including osteopenia and osteoporosis, in HIV patients after receiving long-term TDF-based ART. Furthermore, we may want to avoid using TDF for ART in HIV-infected patients with NAFLD.

Inflammation status in HIV-positive individuals correlates with changes in bone tissue quality after initiation of ART

BACKGROUND

The mechanisms behind ART-induced bone changes in HIV-infected patients are poorly known. We aimed to analyse changes in inflammatory and bone markers in HIV after tenofovir disoproxil fumarate initiation, and the associations with changes in the bone strength parameters.

METHODS

HIV-positive participants starting tenofovir disoproxil fumarate-based ART underwent dual-energy X-ray absorptiometry (QDR 4500 SL®, Hologic, Waltham, MA, USA) for bone mineral density (BMD), a microindentation test (OsteoProbe®, Active Life Scientific, Santa Barbara, CA, USA) for bone quality [bone material strength index (BMSi)] and phlebotomy at baseline and 48 weeks after ART. A panel of inflammatory biomarkers and bone turnover markers were measured by ELISA. HIV-negative controls underwent identical procedures once. Values are expressed as medians and IQRs, and non-parametric tests were used to perform the analysis.

RESULTS

Twenty HIV-infected individuals and 20 HIV-negative control individuals were matched in terms of age and gender. HIV individuals showed higher levels of inflammatory markers. We found no differences in bone turnover markers. HIV-positive individuals presented lower BMSi values at baseline compared with controls [86 (83-90) versus 89 (88-93), respectively; P = 0.034]. We found no difference in BMD (at either of the sites evaluated). BMSi tended to increase with treatment. IL-1β at baseline was positively correlated with changes in BMSi after ART (rho = 0.564, P = 0.014). Baseline levels of sclerostin tended to be negatively correlated with changes in BMSi (rho = -0.402, P = 0.097). We found a negative correlation between time since HIV diagnosis and changes in BMSi (rho = -0.466, P = 0.04).

CONCLUSIONS

We observed a correlation between changes in bone quality and the inflammatory environment in HIV-positive individuals. Moreover, among the underlying mechanisms we highlight the Wnt pathway as having a potentially significant role in ART bone quality recovery.

Circulating sclerostin is associated with bone mineral density independent of HIV-serostatus

Background

Low bone mineral density (BMD) is commonly observed in people living with HIV (PLWH), however the cause for this BMD loss remains unclear. Sclerostin, a bone-derived antagonist to the Wnt/β-catenin-pathway, suppresses bone remodeling and is positively associated with BMD. The goal of the current study was to investigate associations between sclerostin and BMD in a cohort of HIV-seropositive and demographically-matched seronegative women.

Methods

This cross-sectional analysis used a subset of early postmenopausal women enrolled in the Women's Interagency HIV Study (WIHS). BMD was assessed at the lumbar spine, total hip, femoral neck, and distal and ultradistal radius via dual energy x-ray absorptiometry (DXA). Circulating sclerostin was assessed via commercial ELISAs. Univariate and multivariate linear regression modeling tested associations between sclerostin and BMD after adjusting for a variety of BMD-modifying variables.

Results

HIV-seropositive women had significantly reduced BMD at all skeletal sites compared to HIV-seronegative women. There was no difference in sclerostin levels according to HIV-serostatus (0.25 vs 0.27 ng/mL in HIV-seronegative and HIV-seropositive, respectively, p = 0.71). Circulating sclerostin was positively associated with BMD at all sites in both univariate and multivariate models adjusting for HIV status, age, BMI, and race, although the coefficients of association were attenuated in HIV-seropositive women. The positive association between sclerostin and BMD among seropositive women remained statistically significant after adjusting for ART or tenofovir disoproxil fumarate (TDF) use.

Conclusions

The current study suggests that circulating sclerostin is a biomarker for bone mass for both HIV seronegative and seropositive women using and not using ART. The lower coefficients of association between sclerostin and BMD by HIV status may suggest HIV-induced alternation in osteocyte function.

Efficacy and safety of abacavir/lamivudine plus rilpivirine as a first-line regimen in treatment-naïve HIV-1 infected adults

Background

The anti-retroviral combination of abacavir/lamivudine plus rilpivirine (ABC/3TC/RPV) is not recommended by international guidelines as the first-line regimen. However, it is potent, well-tolerated, and affordable, especially in resource-limited settings. This study evaluates the efficacy and safety of ABC/3TC/RPV as an initial regimen for treatment-naïve HIV-1 infected patients.

Methods

A retrospective study was conducted in the largest HIV care centre in Singapore, with data collected June 2011 to September 2017. All treatment-naïve HIV-1 infected adults prescribed ABC/3TC as part of their initial anti-retroviral therapy regimen were included. The third drug was a non-nucleoside reverse-transcriptase inhibitor (NNRTI) such as RPV or efavirenz (EFV), or boosted protease-inhibitor (PI). Patients were followed up for 48 weeks. The primary end-point was the percentage of patients achieving virologic suppression, analysed using on-treatment analysis. Secondary outcomes included CD4-count change, treatment discontinuation and treatment-related adverse events.

Results

170 patients were included in the study, 66 patients in the RPV group, 104 patients in the comparator group (EFV or boosted PI). 96% (n = 24) in the RPV group and 87% (n = 26) in the comparator group achieved viral suppression at 48 weeks (p = 0.28). Median (interquartile range) time to viral suppression was similar: 17 (14–24) weeks in the RPV group, and 21 (13–26) weeks in the comparator group. There were no statistically significant differences in the CD4 count between the two groups. 14% (n = 9) of patients on RPV discontinued treatment before 48 weeks, compared to 30% (n = 31) from the comparator group (p = 0.053). Of these, 23 discontinuations were due to drug adverse effects, and only 1 attributed to RPV (p < 0.01). One patient in each group had virologic failure.

Conclusion

RPV is effective, safe and considerably more tolerable than compared to NNRTI or boosted PI in ABC/3TC-containing regimens for treatment-naïve patients. It offers an affordable and attractive option, especially in resource-limited settings.

Assessment of trabecular bone score, an index of bone microarchitecture, in HIV positive and HIV negative persons within the HIV UPBEAT cohort

Introduction

Increased prevalence of low bone mineral density (BMD) and increased fracture incidence are observed in persons living with HIV (PLWH). The trabecular bone score (TBS) is a novel index of bone microarchitecture which improves fracture prediction independent of BMD.

Methods

The HIV UPBEAT study is a single centre, prospective cohort study that enrolled subjects with and without HIV from similar sociodemographic backgrounds for annual assessments of bone health. TBS was derived from lumbar spine (LS) dual-energy X-ray absorptiometry images. Univariate and multivariable linear regression was used to assess relationships between baseline TBS, BMD, sociodemographic and clinical factors.

Results

463 subjects (201 HIV positive) were included; PLWH were younger and more likely male, of non-African ethnicity and current smokers. HIV was associated with a mean reduction of 0.037 [-0.060, -0.013] (p = 0.002) in TBS. Lower TBS was also associated with male gender, non-African ethnicity, current smoking status and lower LS BMD. HIV remained associated with lower TBS after adjustment for LS BMD, age, gender and ethnicity. However, adjustment for current smoking significantly attenuated the association between HIV and TBS, with further adjustment for higher bone turnover markers largely explaining any residual association. Among the sub-group of PLWH, exposure to protease inhibitors and lower nadir CD4+ T-cell counts were both predictors of lower TBS.

Conclusions

PLWH have lower TBS independent of LS BMD. However, this is largely explained by higher current smoking rates and higher bone turnover in those with HIV. Exposure to PI, but not tenofovir disproxil fumarate, also contributed to lower TBS in those with HIV.

Osteoporosis-Related Fractures in HIV-Infected Patients Receiving Long-Term Tenofovir Disoproxil Fumarate: An Observational Cohort Study

Introduction

Patients with HIV infection may have a higher prevalence of osteoporosis and osteopenia, as well as an increased risk of bone fracture compared with non-HIV-infected individuals. Antiretroviral therapy is thought to be one of factors associated to osteoporosis-related bone fractures.

Objective

The aim of this study was to assess the effects of long-term exposure to tenofovir disoproxil fumarate (TDF) on the cumulative risk of osteoporosis-related bone fractures in Japanese patients with HIV infection.

Design

This observational cohort study comprised a joint HIV-related drug survey of patients treated with TDF between April 2004 and March 2013.

Methods

Thirty-five healthcare facilities in Japan participated in the survey. The incidence of osteoporosis-related fractures was extracted from all adverse events (AEs) using standardized Medical Dictionary for Regulatory Activities queries, and used to calculate the fracture rate per 10,000 patient-years (PY). Kaplan–Meier analysis was used to estimate the cumulative probability of fracture during the study period.

Results

A total of 3251 patients who received TDF or TDF/emtricitabine between April 2004 and March 2013 were analyzed in this study; 93.5% of patients were male. The fracture rate was 13.5 per 10,000 PY in males and 42.2 per 10,000 PY in females. The mean age for male patients with osteoporosis-related fracture was 43.2 years, whereas it was 65.7 years in female patients. The cumulative probability of osteoporosis-related fracture increased after ≥ 5 years of TDF exposure. The rate of hip fracture (95% confidence interval) was 7.2 (3.1–14.2) per 10,000 PY.

Conclusions

Among HIV-infected patients in Japan, treatment with TDF for ≥ 5 years increases the risk of bone fractures in younger men, in addition to that seen in older post-menopausal women.

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.

Changes in bone turnover markers with HIV seroconversion and ART initiation

Background

Osteoporosis is common among HIV-infected persons and contributes to risk of fragility fracture. While ART initiation is associated with decreases in bone mineral density and increases in bone turnover, the impact of HIV on bone metabolism is unclear.

Methods

We identified men at the Chicago site of the Multicenter AIDS Cohort Study who HIV seroconverted while under observation. Concentrations of 25-OH vitamin D, bone turnover markers [procollagen type 1 N terminal propeptide (P1NP), osteocalcin (OC), C-telopeptide (CTX)] and sclerostin were measured from stored serum obtained at pre-HIV infection, pre-ART and post-ART initiation timepoints. Mixed models, with each biomarker as an outcome, were fitted. Timepoint, age, CD4 count (cells/mm 3 ), HIV-viral suppression, season and an age by timepoint interaction term were considered as fixed effects.

Results

Data from 52 participants revealed that median duration between HIV seroconversion and ART initiation was 8.7 years (IQR 3.7-11.6). Median CD4 and plasma HIV-RNA concentrations were 445 (IQR 298.5-689) and 20 184 copies/mL (IQR 6237-64 340), respectively, at the pre-ART timepoint. Multivariate analyses demonstrated pre-HIV infection levels of OC that were higher than pre-ART levels (6.8 versus 5.7 ng/mL, P  =   0.04); and pre-ART levels of sclerostin that were higher than post-ART levels (0.033 versus 0.02 ng/mL, P  <0.001). No changes in P1NP, CTX and 25-OH vitamin D levels were detected.

Conclusions

HIV seroconversion was associated with decreased OC levels while ART initiation was associated with decreases in sclerostin, a negative regulator of bone formation. Our results suggest that both HIV infection and ART have an impact on bone metabolism in white men.

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.

Bone Density, Microarchitecture, and Tissue Quality After Long-Term Treatment With Tenofovir/Emtricitabine or Abacavir/Lamivudine

OBJECTIVES

HIV infection has been associated with reduced bone mineral density (BMD). Antiretroviral therapy (ART) has a deleterious effect on BMD, but its effect on bone fragility is not clear. The objective of this study is to analyze the BMD, microarchitecture, and tissue quality of bone in patients receiving long-term tenofovir- or abacavir-based ART.

DESIGN

We conducted a cross-sectional study in patients with HIV undergoing tenofovir or abacavir ART for more than 5 years.

METHODS

We measured BMD using dual X-ray absorptiometry ,bone michroarchitecture using trabecular bone score (TBS), and bone tissue quality using microindentation. TBS is a dual X-ray absorptiometry-based software that is more highly correlated with bone fragility than BMD. Microindentation (BMSi) directly assesses bone quality at the tissue level.

RESULTS

A total of 63 patients were included in this study, with 36 belonging to the TDF-FTC group and 27 to the ABC-3TC group. Patients receiving TDF-FTC treatment showed lower BMD values than those in the ABC-3TC group. We found no differences in TBS or microindentation between the 2 groups. However, after adjusting for sex, age, body mass index, and 25[OH]vitD we found lower BMSi and thus poorer bone properties in the TDF-FTC group than in the ABC-3TC group [beta coefficient -3.594 (confidence interval: 95% -0.12 to -7.61); P = 0.043].

CONCLUSIONS

Long-term treatment with TDF-FTC leads to impaired bone health, not only in terms of BMD but also in terms of bone quality, another determinant of overall bone strength. To complement BMD-based predictions, these other techniques may also be used to identify patients with excess fracture risk.

Effectiveness and safety of an abacavir/lamivudine + rilpivirine regimen for the treatment of HIV-1 infection in naive patients

OBJECTIVES

To describe the effectiveness and safety of an abacavir/lamivudine + rilpivirine regimen in naive HIV-1-infected patients, as there is a lack of data with this combination.

METHODS

This was an observational, retrospective, multicentre study in eight Spanish hospitals. All antiretroviral-naive patients ≥18 years old and starting abacavir/lamivudine + rilpivirine were included. Effectiveness (ITT and on-treatment) and safety (adverse events and laboratory parameters) were assessed during follow-up. Values are expressed as n (%) or median (IQR). The Wilcoxon signed-rank test was used to compare baseline and 6 and 12 month values.

RESULTS

Eighty-four patients were included [93% males, age = 36 (30-45) years]. Time since HIV diagnosis was 12 (4-35) months. Fifty-one per cent of patients had comorbidities. Baseline CD4+ was 425 (340-519) cells/mm³ and baseline HIV-RNA was 19 000 (9500-42 000) copies/mL. Median follow-up was 18 (9-22) months; 100% and 68% patients with at least 6 and 12 months, respectively. At 6 and 12 months effectiveness was 94% and 86% by ITT analysis and 96% and 97% by on-treatment analysis. At 12 months, there were significant increases in CD4+ (+262 cell/mm³) and HDL cholesterol (+4 mg/dL) and a significant decrease in the total cholesterol/HDL cholesterol ratio (-0.2). There were two (2.4%) virological failures (HIV-RNA 50-100 copies/mL); one patient later achieving virological suppression without changing the treatment. Six patients (7.1%) changed treatment due to reasons other than virological failure or side effects. One patient discontinued treatment due to gastrointestinal complaints attributed to abacavir/lamivudine.

CONCLUSIONS

Abacavir/lamivudine + rilpivirine was an effective and safe option in a selected group of HIV-1-infected treatment-naive patients.

Usefulness of calcaneal quantitative ultrasound stiffness for the evaluation of bone health in HIV-1-infected subjects: comparison with dual X-ray absorptiometry

Objectives

With the development of effective treatments and the resulting increase in life expectancy, bone mineral density (BMD) alteration has emerged as an important comorbidity in human immunodeficiency virus type-1 (HIV-1)-infected individuals. The potential contributors to the pathogenesis of osteopenia/osteoporosis include a higher prevalence of risk factors, combined antiretroviral therapy (cART)-exposure, HIV-1 itself and chronic immune activation/inflammation. Dual-energy X-ray absorptiometry (DXA) is the “gold standard” technique for assessing bone status in HIV-1 population.

Methods

We conducted a cross-sectional study to investigate bone mineral status in a group of 158 HIV-1-infected subjects. The primary endpoint was the feasibility of calcaneal quantitative ultrasound (QUS) as a screening tool for BMD. All subjects were receiving stable cART and were virologically suppressed (HIV-RNA <37 copies/mL) from at least 12 months. Calcaneal QUS parameters were analyzed to obtain information on bone mass and microarchitecture. The results were compared with those obtained by DXA.

Results

No correlations were found between DXA/QUS parameters and demographic or HIV-1-specific characteristics, also including cART strategies. In the univariate analyses BMD, QUS indexes, and Fracture Risk Assessment Tool scores conversely showed significant associations with one or more demographic or HIV-1-related variables. Moreover, a significant relationship between calcaneal quantitative ultrasound index/stiffness and femoral/lumbar BMD values from DXA was described. The multivariate analysis showed an independent association between calcaneal quantitative ultrasound index/stiffness and body mass index, higher CD4+ T-cell numbers and low 25-OH D2/D3 vitamin D levels <10 ng/mL (P-values: 0.004, 0.016, and 0.015, respectively).

Conclusion

As an alternative and/or integrative examination to DXA, calcaneal QUS could be proposed as a useful screening in HIV-1-infected patients for assessing bone health impairment. In fact, the results obtained confirm that calcaneal QUS may be useful for monitoring bone status, being a noninvasive and inexpensive technique, especially in those subjects with the classical traditional risk factors for bone damage that were observed earlier in HIV-1 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.

Bone loss in HIV: a contemporary review

PURPOSE OF REVIEW

Because of antiretroviral therapy (ART), people are living with HIV infection longer than ever before. As this patient group ages, it is expected that medical comorbidities such as osteoporosis and fragility fractures will increase. The purpose of this review is to address the epidemiology and what is known regarding the pathogenesis of bone loss in people living with HIV infection with a focus on recently published literature.

RECENT FINDINGS

HIV-infected individuals are at increased risk for low bone mineral density and bone fractures. The cause of bone loss in HIV is multifactorial including traditional risk factors some of which disproportionately affect HIV-infected individuals and alterations in bone metabolism due to ART, HIV viral proteins and chronic inflammation. Lifestyle modification, changing ART, calcium and vitamin D supplementation and pharmacologic treatment for osteoporosis may all be employed to abrogate bone loss in this patient group.

SUMMARY

Clinicians should be aware of the contributors to bone loss in people living with HIV in order to recognize high-risk individuals and to take appropriate steps to address modifiable risk factors to prevent future fracture.

Improvement in renal function and bone mineral density after a switch from tenofovir/emtricitabine plus ritonavir-boosted protease inhibitor to raltegravir plus nevirapine: a pilot study

BACKGROUND

The antiretroviral regimens including tenofovir and a ritonavir-boosted protease inhibitor (r/PI) have been associated with a reduced bone mineral density (BMD), increased bone turnover markers and renal tubular dysfunction.

METHODS

An observational, prospective study was performed including HIV-1-infected, virologically suppressed patients treated with tenofovir/emtricitabine plus an r/PI for at least 12 months who switched to raltegravir plus nevirapine. The primary end point was changes after 48 weeks in estimated glomerular filtration rate (eGFR), prevalence of tubular dysfunction, BMD and concentration of two serum markers of bone turnover: collagen type-1 cross-linked C-telopeptide (CTX) and bone-specific alkaline phosphatase (BAP).

RESULTS

A total of 46 patients were enrolled: 78% were male, 96% were Caucasian, the mean age was 45 years and the mean CD4(+) T-lymphocyte count was 681 cells/mm(3). A renal impairment was present in 72% of patients and was the main reason for the switch. After 48 weeks, prevalence of proximal tubular dysfunction decreased significantly (-72%; P<0.001), whereas the mean value of eGFR did not change significantly. At the same time, after 48 weeks a significant increase in both lumbar spine and total hip BMD, T-score and Z-score was reported (+11.5% in lumbar spine T-score; P<0.001), and there was a significant reduction in both CTX and BAP mean serum concentrations (-15% and -13%, respectively; P<0.001). Two (4.3%) patients had virological failure due to suboptimal adherence and one (2.2%) subject discontinued treatment due to a skin rash.

CONCLUSIONS

Switching virologically suppressed patients from tenofovir/emtricitabine plus one r/PI to raltegravir plus nevirapine after 48 weeks significantly improved proximal tubular function, increased BMD and reduced serum markers of bone turnover.

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.