Assessment of radiological vertebral fractures in HIV-infected patients: clinical implications and predictive factors

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.

Evaluation of bone mineral density, microarchitecture, and detection of fractures on young patients living with human immunodeficiency virus: when and how to screen?

PURPOSE

People living with the human immunodeficiency virus (PLWH) developed higher life expectancy along with chronic bone disease over the past years. Our purpose is to evaluate bone mineral density, bone microarchitecture and fractures in young PLWH and understand the disease's contribution to bone derangements and fracture risk.

METHODS

Eighty-one HIV-infected and 54 control young (20-50 years) male and female subjects were enrolled in this study. Methods for patient evaluation included DXA-VFA (dual energy X-rays and vertebral fracture assessment), HR-pQCT (high resolution peripheral quantitative computed tomography), biochemistry and FRAX.

RESULTS

Fifty participants from each group completed all exams. Median age was 40 (25-49) vs. 36.5 (22-50) for the HIV and control groups, respectively (p 0.120). Ethnicity, body mass index, serum phosphorus, 25-hydroxyvitamin D, PTH and CTX were similar between groups, although ALP and OC suggested higher bone turnover in PLWH. VFA identified morphometric vertebral fractures in 12% of PLWH. PLWH had lower values for lumbar spine areal BMD and Z score, volumetric BMD, trabecular bone fraction (BV/TV) and trabecular number measured at the distal tibia by HR-pQCT; as a consequence, trabecular separation and heterogeneity were higher (all p < 0.05). The FRAX-estimated risk for hip and major osteoporotic fractures was statistically higher in PLWH (p < 0.001).

CONCLUSION

Our results confirm severe bone impairment and fractures associated with HIV in young patients. Thus, we developed a screening protocol for young PLWH to detect bone fragility, reduce skeletal disease progression and morbimortality, decrease fracture risk, and increase quality of life.

Red flags to screen for vertebral fracture in people presenting with low back pain

BACKGROUND

Low back pain is a common presentation across different healthcare settings. Clinicians need to confidently be able to screen and identify people presenting with low back pain with a high suspicion of serious or specific pathology (e.g. vertebral fracture). Patients identified with an increased likelihood of having a serious pathology will likely require additional investigations and specific treatment. Guidelines recommend a thorough history and clinical assessment to screen for serious pathology as a cause of low back pain. However, the diagnostic accuracy of recommended red flags (e.g. older age, trauma, corticosteroid use) remains unclear, particularly those used to screen for vertebral fracture.

OBJECTIVES

To assess the diagnostic accuracy of red flags used to screen for vertebral fracture in people presenting with low back pain. Where possible, we reported results of red flags separately for different types of vertebral fracture (i.e. acute osteoporotic vertebral compression fracture, vertebral traumatic fracture, vertebral stress fracture, unspecified vertebral fracture).

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 26 July 2022.

SELECTION CRITERIA

We considered primary diagnostic studies if they compared results of history taking or physical examination (or both) findings (index test) with a reference standard test (e.g. X-ray, magnetic resonance imaging (MRI), computed tomography (CT), single-photon emission computerised tomography (SPECT)) for the identification of vertebral fracture in people presenting with low back pain. We included index tests that were presented individually or as part of a combination of tests.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data for diagnostic two-by-two tables from the publications or reconstructed them using information from relevant parameters to calculate sensitivity, specificity, and positive (+LR) and negative (-LR) likelihood ratios with 95% confidence intervals (CIs). We extracted aspects of study design, characteristics of the population, index test, reference standard, and type of vertebral fracture. Meta-analysis was not possible due to heterogeneity of studies and index tests, therefore the analysis was descriptive. We calculated sensitivity, specificity, and LRs for each test and used these as an indication of clinical usefulness. Two review authors independently conducted risk of bias and applicability assessment using the QUADAS-2 tool.

MAIN RESULTS

This review is an update of a previous Cochrane Review of red flags to screen for vertebral fracture in people with low back pain. We included 14 studies in this review, six based in primary care, five in secondary care, and three in tertiary care. Four studies reported on 'osteoporotic vertebral fractures', two studies reported on 'vertebral compression fracture', one study reported on 'osteoporotic and traumatic vertebral fracture', two studies reported on 'vertebral stress fracture', and five studies reported on 'unspecified vertebral fracture'. Risk of bias was only rated as low in one study for the domains reference standard and flow and timing. The domain patient selection had three studies and the domain index test had six studies rated at low risk of bias. Meta-analysis was not possible due to heterogeneity of the data. Results from single studies suggest only a small number of the red flags investigated may be informative. In the primary healthcare setting, results from single studies suggest 'trauma' demonstrated informative +LRs (range: 1.93 to 12.85) for 'unspecified vertebral fracture' and 'osteoporotic vertebral fracture' (+LR: 6.42, 95% CI 2.94 to 14.02). Results from single studies suggest 'older age' demonstrated informative +LRs for studies in primary care for 'unspecified vertebral fracture' (older age greater than 70 years: 11.19, 95% CI 5.33 to 23.51). Results from single studies suggest 'corticosteroid use' may be an informative red flag in primary care for 'unspecified vertebral fracture' (+LR range: 3.97, 95% CI 0.20 to 79.15 to 48.50, 95% CI 11.48 to 204.98) and 'osteoporotic vertebral fracture' (+LR: 2.46, 95% CI 1.13 to 5.34); however, diagnostic values varied and CIs were imprecise. Results from a single study suggest red flags as part of a combination of index tests such as 'older age and female gender' in primary care demonstrated informative +LRs for 'unspecified vertebral fracture' (16.17, 95% CI 4.47 to 58.43). In the secondary healthcare setting, results from a single study suggest 'trauma' demonstrated informative +LRs for 'unspecified vertebral fracture' (+LR: 2.18, 95% CI 1.86 to 2.54) and 'older age' demonstrated informative +LRs for 'osteoporotic vertebral fracture' (older age greater than 75 years: 2.51, 95% CI 1.48 to 4.27). Results from a single study suggest red flags as part of a combination of index tests such as 'older age and trauma' in secondary care demonstrated informative +LRs for 'unspecified vertebral fracture' (+LR: 4.35, 95% CI 2.92 to 6.48). Results from a single study suggest when '4 of 5 tests' were positive in secondary care, they demonstrated informative +LRs for 'osteoporotic vertebral fracture' (+LR: 9.62, 95% CI 5.88 to 15.73). In the tertiary care setting, results from a single study suggest 'presence of contusion/abrasion' was informative for 'vertebral compression fracture' (+LR: 31.09, 95% CI 18.25 to 52.96).

AUTHORS' CONCLUSIONS

The available evidence suggests that only a few red flags are potentially useful in guiding clinical decisions to further investigate people suspected to have a vertebral fracture. Most red flags were not useful as screening tools to identify vertebral fracture in people with low back pain. In primary care, 'older age' was informative for 'unspecified vertebral fracture', and 'trauma' and 'corticosteroid use' were both informative for 'unspecified vertebral fracture' and 'osteoporotic vertebral fracture'. In secondary care, 'older age' was informative for 'osteoporotic vertebral fracture' and 'trauma' was informative for 'unspecified vertebral fracture'. In tertiary care, 'presence of contusion/abrasion' was informative for 'vertebral compression fracture'. Combinations of red flags were also informative and may be more useful than individual tests alone. Unfortunately, the challenge to provide clear guidance on which red flags should be used routinely in clinical practice remains. Further research with primary studies is needed to improve and consolidate our current recommendations for screening for vertebral fractures to guide clinical care.

Negative correlation between bone mineral density and subclinical fractures in patients with human immunodeficiency virus

Background

Although low bone mineral density (BMD) is associated with an increased risk of fracture, few studies have assessed fracture rates in patients with human immunodeficiency virus (HIV).

Methods

The occurrence of subclinical fractures in patients with HIV was assessed. Pearson’s chi-square test was used to analyze the relationship between subclinical fractures and related factors.

Results

Fifty patients with HIV were included, among whom 11 were diagnosed with subclinical fractures. These 11 patients had a mean body mass index of 24.127 ± 3.482 kg/m², smoked a mean of 142.091 ± 3.482 cigarettes/month, drank a mean of 61.545 ± 13.026 mL/day of alcohol, had a mean CD4⁺ T cell count of 247.727 ± 181.679 cells/mm³, had a mean duration of acquired immunodeficiency syndrome (AIDS) of 4.27 ± 0.786 years, and had a mean BMD of the third lumbar spine of 0.810 ± 0.063 g/cm³. The AIDS duration and BMD of the third lumbar spine were significantly associated with subclinical fractures. The BMD of the third lumbar spine was negatively correlated with subclinical fractures.

Conclusion

A significant negative correlation was found between the BMD of the third lumbar spine and subclinical fractures.

Bone fracture among people living with HIV: A systematic review and meta-regression of prevalence, incidence, and risk factors

Introduction

People living with HIV (PLWH) had a higher prevalence and incidence rate of bone fracture compared to general population. Although several studies have explored this phenomenon, the prevalence and incidence rate of fracture were varied.

Objective

The aim of the study is to determine and analyze the pooled prevalence, incidence rate of fracture and fracture risk factors among people living with HIV (PLWH).

Methods

PubMed, Cochrane Library, CINAHL with full Text, and Medline databases for studies published up to August 2019 were searched. Studies reporting the prevalence or incidence of fracture among PLWH were included. Study quality was assessed using the Joanna Briggs Institute (JBI) appraisal tool. A meta-analysis with random-effects model was performed to determine pooled estimates of prevalence and incidence rates of fracture. A meta-regression was performed to determine the source of heterogeneity.

Results

The pooled estimated prevalence of fracture among PLWH was 6.6% (95% CI: 3.8–11.1) with pooled odds ratio of 1.9 (95%CI: 1.1–3.2) compared to the general population. The pooled estimates of fracture incidence were 11.3 per 1000 person-years (95% CI: 7.9–14.5) with incidence rate ratio (IRR) of 1.5 (95% CI: 1.3–1.8) compared to the general population. Risk factors for fracture incidence were older age (aHR 1.4, 95% CI: 1.3–1.6), smoking (aHR 1.3, 95% CI: 1.1–1.5), HIV/HCV co-infection (aHR 1.6, 95% CI: 1.3–1.9), and osteoporosis (aHR 3.3, 95% CI: 2.2–5.1).

Conclusions

Our finding highlights a higher risk of fracture among PLWH compared to the general population. Osteoporosis, smoking and HIV/HCV coinfection as the significant modifiable risk factors should be prioritized by the HIV health providers when care for PLWH.

High risk and probability of progression to osteoporosis at 10 years in HIV-infected individuals: the role of PIs

Background

Osteoporotic fractures still remain very infrequent and physicians rarely evaluate bone health. We wanted to assess the magnitude of this problem in the near future by determining the risk and likelihood of progression to osteoporosis.

Methods

We estimated the risk of progression to osteopenia/osteoporosis among HIV-infected patients with at least 2 DXA scans (3726 scans from 875 patients). Time-non-homogeneous bidirectional multistate models based on three states (normal bone mineral density, osteopenia and osteoporosis) were used to model the progression of bone mineral density as a function of age and to study the association between the risk of bone loss and antiretroviral use.

Results

The HRs associated with age (>45 versus ≤45 years) were: (i) from normal bone mineral density to osteopenia, 0.71 (95% CI 0.45-1.11) for men and 1.06 (95% CI 0.55-2.05) for women; and (ii) from osteopenia to osteoporosis, 0.83 (95% CI 0.51-1.35) for men and 0.99 (95% CI 0.38-2.56) for women. The transition probabilities from osteopenia to osteoporosis over 10 years among men aged 30 and 50 years were 14.9% (95% CI 10.5%-20.4%) and 19% (95% CI 14.3%-24.3%), respectively; and for women, 6.9% (95% CI 3.1%-14.4%) and 30.1% (95% CI 19.8%-41.8%), respectively. An increased osteoporosis risk was observed for PIs and PIs + tenofovir disoproxil fumarate; darunavir was associated with a higher risk of osteoporosis among men (HR 3.9; 95% CI 2-7.5) and women (HR 4.5; 95% CI 1.4-14.7); and atazanavir was associated with a higher risk of osteoporosis among women (HR 4.2; 95% CI 1.3-14).

Conclusions

Our results highlight the importance of monitoring bone mineral density given the high probability of progression to osteopenia/osteoporosis, especially in women. In the future, changes in antiretrovirals other than tenofovir, such as PIs, should be recommended to reduce the risk of fracture.

CD4 T cell count is inversely associated with lumbar spine bone mass in HIV-infected men under the age of 50 years

HIV-infected men under the age of 50 years had a lower bone mass compared to that of HIV-uninfected men. Lower CD4 T cell counts, independent of whether antiretroviral therapy (ART) was used, were associated with lower BMD. HIV-infected patients with low CD4 T cell counts may need follow-up and intervention regarding bone health, including younger patients.

INTRODUCTION

HIV-infected patients have a low bone mineral density (BMD) owing to multifactorial interaction between common osteoporosis risk factors and HIV-related factors, including chronic inflammation and ART. Although HIV infection and ART might affect bone metabolism, little data is available for patients aged under 50 years. We aimed to investigate the association of HIV infection-induced low CD4 T cell counts and ART with BMD in men aged under 50 years.

METHODS

We performed an age- and body mass index-matched case-control study. BMD values of HIV-infected and HIV-uninfected men (< 50 years) were compared, and HIV-infected men were stratified by CD4 T cell counts and ART use.

RESULTS

After adjusting confounders, HIV-infected men with CD4 T cell counts ≥ 500 cells/μL (n = 28) and < 500 cells/μL (n = 139) had lower BMD at the femoral neck (FN, p < 0.001) and total hip (TH, p < 0.001) than HIV-uninfected men (n = 167). HIV-infected men with CD4 T cell counts < 500/μL had lower BMD at the lumbar spine (LS, p = 0.034) than those with counts of ≥ 500 cells/μL, but not at FN and TH. The CD4 T cell count (γ = 0.169, p = 0.031) was positively correlated with BMD at LS. There was no significant difference in the BMD (p = 0.499-> 0.999) between the ART-naïve (n = 75) and ART-user group (n = 92).

CONCLUSIONS

Despite their relatively younger age, HIV-infected men had a lower BMD than HIV-uninfected men. Lower CD4 T cell counts, irrespective of ART, might result in lower bone mass.

HIV and Vertebral Fractures: a Systematic Review and Metanalysis

The survival of HIV-infected patients has increased with the advent of antiretroviral therapy with the emergence of new comorbidities. Vertebral fracture is a manifestation of reduced bone strength and osteoporosis. This study aims to assess the frequency of spine fractures in HIV-positive men and women aged over 18 years. We performed a systematic review of randomized controlled trials, cohort studies, cross-sectional studies, and case-control studies. Studies that evaluated morphometric and/or clinical vertebral fracture were included. In total 488 studies were found, of which 53 had their full texts evaluated. A total of 85,411 HIV positive individuals were identified in 26 studies. The meta-analysis of the prevalence of vertebral fractures included 12 studies with 10,593 subjects. The prevalence was 11.1% [95% confidence interval (95% CI) 4.5%, 25.0%, I² 98.2% p < 0.00001]. When we evaluated independently studies of clinical vertebral fracture and morphometric vertebral fracture, the prevalence was 3.9% (95% CI 0.9, 15.8, I² 96.4% p < 0.00001) and 20.2% (95% CI 15.7%, 25.6%, I² 69.9% p = 0.003) respectively. HIV-infected individuals had an odds ratio of vertebral fractures of 2.3 (95% CI 1.37, 3.85, I² 98.2% p < 0.00001) when compared with HIV-uninfected patients (n = 9 studies). In conclusion, HIV-positive subjects had a higher risk of vertebral fractures when compared with HIV-negative subjects.

Increased prevalence of asymptomatic vertebral fractures in HIV-infected patients over 50 years of age

The prevalence of asymptomatic vertebral fracture in HIV-infected patients over 50 was 20%, associated with older age, male sex, longer time since HIV diagnosis, and tubular renal alterations. Vertebral fractures were independent of osteoporosis at lumbar spine, and were not predicted by the use of the FRAX equation.

PURPOSE

Vertebral fractures (VF) are the hallmark of osteoporotic fractures. Our objective was to determine the prevalence of asymptomatic VF and associated factors in HIV-infected patients over 50 years, and the role of FRAX equation.

METHODS

In a cross-sectional study, a diagnosis of VF was established by the semiquantitative method of Genant in thoracic and lumbar radiographs. Simultaneously, a dual X-ray absorptiometry (DXA), bone and kidney-related analytical, calcium intake, physical exercise, HIV-related factors, and FRAX estimation were evaluated.

RESULTS

Overall, 128 patients (35 women, 27%) were included. Mean age was 57 years. Hypophosphatemia and tubular renal dysfunction were observed in 13 and 21%. DXA scan showed osteopenia and osteoporosis at hip in 65 and 7% of patients, and in spine in 39 and 34%, respectively. VF were observed in 26 patients (20%), with a trend to be associated with lower serum phosphate, increased alkaline phosphatase, and with lower daily calcium intake. In a multivariate analysis, older age (OR 1.2 per year; 14% of VF at 50-55; 44% at 65-70), male sex (26 vs 6%), longer time since HIV diagnosis, and renal and tubular dysfunction were the associated factors. VF were not related with osteoporosis at lumbar spine, and could not be predicted by the FRAX equation.

CONCLUSIONS

The prevalence of asymptomatic vertebral fractures is high in HIV-infected patients older than 50 years, and is not identified by the presence of osteoporosis in spine neither predicted by the FRAX equation. Spine and lumbar X-rays should be routinely performed in this aging population.

Bone density, microarchitecture, and tissue quality after 1 year of treatment with tenofovir disoproxil fumarate

OBJECIVE

Bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) is used to assess bone health in HIV patients. DXA measures the amount of mineral, but not other key aspects of bone strength such as bone microarchitecture or bone quality. Trabecular bone score (TBS) and in-vivo microindentation directly measure trabecular microarchitecture and bone tissue quality, respectively. The aim of this study is to measure bone strength properties using these techniques.

RESULTS

Forty naive HIV patients who were going to start antiretroviral therapy (ART), a single pill treatment with elvitegravir/cobicistat, tenofovir disoproxil fumarate (TDF), emtricitavine (FTC) were included. A significant reduction in BMD at spine (-3.25%, P < 0.001) and in femoral neck (-3.82%, P = 0.016) between baseline and 48 weeks of treatment were found. Bone microarchitecture score at the spine, as measured by TBS, also significantly decreased from 1.357 (0.09) to 1.322 (0.09) (-2.5%, P = 0.011) between baseline to 48 weeks of treatment. Microindentation (BMSi) values were significantly higher than at baseline [89.04 (4.2) versus 86.07 (6.1); 3.49%, P < 0.001] after 48 weeks of TDF-based ART treatment, indicating improved bone material properties CONCLUSION:: A significant decrease in BMD and TBS were observed after 1 year of TDF therapy. However, tissue quality significantly improved after 1 year of treatment, suggesting a recovery of bone material properties following the control of the infection despite the significant reduction of BMD. These techniques provide additional and necessary information to DXA about bone health in treated HIV patients, and because of its convenience and feasibility they could be routinely apply to assess bone in clinical practice.

Vitamin D Status and the Relationship with Bone Fragility Fractures in HIV-Infected Patients: A Case Control Study

HIV-infected patients show high risk of fracture. The aims of our study were to determine the prevalence of vertebral fractures (VFs) and their associations with vitamin D in HIV patients. 100 patients with HIV infection and 100 healthy age- and sex-matched controls were studied. Bone mineral density was measured by quantitative ultrasound at the non-dominant heel. Serum osteocalcin and C-terminal telopeptide of collagen type 1 served as bone turnover markers. Bone ultrasound measurements were significantly lower in patients compared with controls (Stiffness Index (SI): 80.58 ± 19.95% vs. 93.80 ± 7.10%, respectively, p < 0.001). VFs were found in 16 patients and in 2 controls. HIV patients with vertebral fractures showed lower stiffness index (SI) (70.75 ± 10.63 vs. 83.36 ± 16.19, respectively, p = 0.045) and lower vitamin D levels (16.20 ± 5.62 vs. 28.14 ± 11.94, respectively, p < 0.02). The majority of VFs (87.5%) were observed in HIV-infected patients with vitamin D insufficiency, and regression analysis showed that vitamin D insufficiency was significantly associated with vertebral fractures (OR 9.15; 95% CI 0.18–0.52, p < 0.04). VFs and are a frequent occurrence in HIV-infected patients and may be associated with vitamin D insufficiency.

Trabecular bone score (TBS) is associated with sub-clinical vertebral fractures in HIV-infected patients

Fragility fractures risk is increased among HIV infected patients. Bone microstructure alterations, in addition to bone mineral density (BMD) reduction, might be responsible for the increased risk. The aim of this study was to determine the prevalence of vertebral fractures (VFs) and their association with trabecular bone score (TBS), an indirect index of bone microstructure, in a cohort of HIV-infected subjects. One-hundred and forty-one HIV-infected patients (87% males, median age 43 years, 94% on stable antiretroviral therapy with undetectable viral load) underwent viro-immunological and bone metabolism biochemical screenings. Lumbar TBS and BMD at femoral neck, total hip, and lumbar spine, were measured with dual-energy X-ray absorptiometry (DXA). VFs were identified using the semiquantitative method and quantitative morphometric analysis from thoracic and lumbar spine X-ray images. VFs were observed in 19 patients (13.5%). BMD was below the expected range for age in 18 (12.8%) subjects. No significant differences were found stratifying VFs prevalence by BMD, whereas patients with lower TBS showed a higher prevalence of VFs (p = 0.03). In multivariate analysis, TBS was the only factor significantly associated to VFs (OR = 0.56; 95% CI = 0.33-0.96; p = 0.034), with increased fracture risk for lower TBS values. VFs are prevalent and associated with low TBS among HIV-positive patients, whereas no significant association was found with BMD.

Comparison between the gold standard DXA with calcaneal quantitative ultrasound based-strategy (QUS) to detect osteoporosis in an HIV infected cohort

Introduction

Osteoporosis represents one of the most frequent comorbidity among HIV patients. The current standard method for osteoporosis diagnosis is dual-energy X-ray absorptiometry. Calcaneal quantitative ultrasound can provide information about bone quality. The aims of this study are to compare these two methods and to evaluate their ability to screen for vertebral fracture.

Methods

This cross-sectional study was conducted in HIV patients attending the Clinic of Infectious and Tropical Diseases of Brescia during 2014 and who underwent lumbar/femoral dual-energy X-ray absorptiometry, vertebral fracture assessment and calcaneal quantitative ultrasound. The assessment of osteoporosis diagnostic accuracy was performed for calcaneal quantitative ultrasound and for vertebral fracture comparing them with dual-energy X-ray absorptiometry.

Results

We enrolled 73 patients and almost 48% of them had osteoporosis with at least one of the method used. Vertebral fracture were present in 27.4%. Among patients with normal bone measurements, we found vertebral fracture in proportion between 10% and 30%. If we used calcaneal quantitative ultrasound method and/or X-ray as screening, the percentages of possible savable dual-energy X-ray absorptiometry ranged from 12% to 89% and misclassification rates ranged from 0 to 24.6%. A combined strategy, calcaneal quantitative ultrasound and X-Ray, identified 67% of patients with low risk of osteoporosis, but 16.4% of patients were misclassified.

Conclusions

We observed that patients with osteoporosis determined by calcaneal quantitative ultrasound and/or dual-energy X-ray absorptiometry have higher probability to undergo vertebral fracture, but neither of them can be used for predicting vertebral fracture. Use of calcaneal quantitative ultrasound for screening is a reasonable alternative of dual-energy X-ray absorptiometry since our study confirm that none strategy is clearly superior, but both screen tools must be always completed with X-ray.

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.

Do people with HIV infection have a higher risk of fracture compared with those without HIV infection?

PURPOSE OF REVIEW

This review details recent findings that inform the prevalence and incidence of fractures in people living with HIV (PLWH) and examines the effects of HIV infection and antiretroviral therapy (ART), as well as demographics and traditional risk factors on fractures. As antiretroviral guidelines have recently changed to recommend the introduction of ART at diagnosis of HIV infection, the long-term effects of ART on bone health and fracture risk need to be better understood.

RECENT FINDINGS

It is apparent that both the effects of HIV infection alone and initiation of ART are associated with significant bone loss in individuals with HIV infection, resulting in osteopenia and osteoporosis. The clinical consequence of low bone mineral density is a greater risk of fragility fractures that are more common in older HIV patients, and those on ART. Frailty occurs at a prevalence of about 10% (about twice that of the general population), and the increased propensity of falls results in greater fracture prevalence, morbidity and mortality.

SUMMARY

This review examines data from recent cohort studies and clinical trials to inform a better understanding of the complex relationship between the effects of HIV infection, ART and demographics on fractures in PLWH.

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.

Antiretroviral Treatment Efficacy and Safety in Older HIV-Infected Adults

Highly active antiretroviral therapy (ART) and its widespread availability have revolutionized the landscape of HIV care and patient outcomes, transforming infection with HIV into a manageable chronic condition rather than a life-limiting disease. This transformation has created an older patient demographic. The effect that older age has on the outcomes of ART is not completely understood. Limited data are available in older individuals due to underrepresentation in clinical trials. To better understand this relationship, we conducted a literature search to assess the impact of older age on the outcomes of ART in the older HIV-infected population, including immunologic and virologic outcomes, mortality, disease progression, toxicity of ART, and pharmacokinetic considerations. In addition, package inserts of antiretroviral (ARV) medications were reviewed for efficacy, safety, and pharmacokinetic information pertaining to the older population. Most studies in older adults (50 yrs or older) demonstrated slower and blunted CD4 immune recovery but better virologic suppression in response to ART. Higher rates of mortality and faster disease progression have been observed in adults 50 years and older, particularly during the first year after ART initiation. HIV-infected patients aged 50 years and older appear to be at greater risk for certain ART-associated toxicities including nephrotoxicity, decline in bone mineral density and bone fracture, symptomatic peripheral neuropathy, and cardiovascular disease including myocardial infarction. The available literature suggests that clinicians should consider avoiding agents such as tenofovir disoproxil fumarate (TDF) in older patients with risk factors for renal impairment and/or osteoporosis. If TDF is used in patients aged 50 years or older, more frequent monitoring should be considered. Older age was a significant predictor for higher atazanavir exposure and higher lopinavir trough concentration at 24 weeks. The clinical implications of these findings are unknown. It is imperative that future development of novel ARV drug therapies includes a greater proportion of older subjects in clinical trials.

Contribution of Genetic Background and Clinical Risk Factors to Low-Trauma Fractures in Human Immunodeficiency Virus (HIV)-Positive Persons: The Swiss HIV Cohort Study

Background. The impact of human genetic background on low-trauma fracture (LTF) risk has not been evaluated in the context of human immunodeficiency virus (HIV) and clinical LTF risk factors.

Methods. In the general population, 6 common single-nucleotide polymorphisms (SNPs) associate with LTF through genome-wide association study. Using genome-wide SNP arrays and imputation, we genotyped these SNPs in HIV-positive, white Swiss HIV Cohort Study participants. We included 103 individuals with a first, physician-validated LTF and 206 controls matched on gender, whose duration of observation and whose antiretroviral therapy start dates were similar using incidence density sampling. Analyses of nongenetic LTF risk factors were based on 158 cases and 788 controls.

Results. A genetic risk score built from the 6 LTF-associated SNPs did not associate with LTF risk, in both models including and not including parental hip fracture history. The contribution of clinical LTF risk factors was limited in our dataset.

Conclusions. Genetic LTF markers with a modest effect size in the general population do not improve fracture prediction in persons with HIV, in whom clinical LTF risk factors are prevalent in both cases and controls.

Management of bone mineral density in HIV-infected patients

INTRODUCTION

Loss of bone mineral density is an emerging problem in persons living with HIV infection. Earlier and more rapid bone demineralization has been attributed not only to the high prevalence of traditional risk factors, but also to specific HIV-related factors. The aim of this guidance is to stimulate an appropriate management of osteoporosis in this population, to identify patients at risk and to better manage them.

AREAS COVERED

Appropriate screening of HIV-infected subjects to identify those at risk for bone fractures is described, as well as the recommended interventions. American and European recommendations in HIV-infected and non-infected populations were considered. As the etiology of bone loss is multifactorial, many factors have to be addressed. Overall, recommendations on traditional risk factors are the same for HIV-infected and non-HIV-infected subjects. However, we should consider some specific factors in the HIV-infected population, including an appropriate antiretroviral therapy in patients with low bone mineral density, and probably novel strategies that could provide an additional benefit, such as anti-inflammatory drugs, although data supporting this approach are scant.

EXPERT OPINION

Some personal opinions are highlighted on the management of bone health in HIV-infected subjects, mainly on the use of FRAX(®) score and DXA scans. In addition, the need to implement new strategies to delay demineralization is remarked upon.