Low CD4 count is associated with an increased risk of fragility fracture in HIV-infected patients

Association between CD4 + cell count, CD4/CD8 ratio, and fragility fractures in people with HIV

BACKGROUND

People with HIV (PWH) often exhibit reduced CD4 + T cell counts and altered CD4/CD8 ratios, but their impact on fragility fractures remains underexplored. This study investigated the association between CD4 + cell count, CD4/CD8 ratio, and fragility fractures in PWH in China.

METHODS

A retrospective cohort study was conducted on PWH treated at Beijing Ditan Hospital from January 2011 to September 2023. Data on demographics, clinical status, and bone mineral density were collected. Fragility fractures were identified through medical records. Multivariate Cox regression was used to assess the relationship between CD4 + cell count, CD4/CD8 ratio, and fracture risk, with restricted cubic splines (RCS) applied to explore potential nonlinear associations. Subgroup analyses evaluated the consistency of these findings.

RESULTS

The study included 1107 participants (median age 37 years, 92.6% male). The median CD4 + cell count was 547 cells/μl, and the median CD4/CD8 ratio was 0.7. Fragility fractures occurred in 185 participants (16.7%). Lower CD4 + cell counts (<200 cells/μl) were associated with a higher risk of fractures [aHR = 2.78; 95% confidence interval (95% CI): 1.66-4.65; P  < 0.001], as were lower CD4/CD8 ratios (<0.5) (aHR = 3.43; 95% CI: 2.16-5.44; P  < 0.001). RCS indicated a curvilinear association, with increased fracture risk at CD4/CD8 ratios below 1.16. Subgroup analyses confirmed the stability of these associations.

CONCLUSION

Lower CD4 + cell counts and CD4/CD8 ratios are linked to an increased risk of fragility fractures in PWH, underscoring the importance of immune function in bone health.

An explainable web application based on machine learning for predicting fragility fracture in people living with HIV: data from Beijing Ditan Hospital, China

Purpose

This study aimed to develop and validate a novel web-based calculator using machine learning algorithms to predict fragility fracture risk in People living with HIV (PLWH), who face increased morbidity and mortality from such fractures.

Method

We retrospectively analyzed clinical data from Beijing Ditan Hospital orthopedic department between 2015 and September 2023. The dataset included 1045 patients (2015-2021) for training and 450 patients (2021-September 2023) for external testing. Feature selection was performed using multivariable logistic regression, LASSO, Boruta, and RFE-RF. Six machine learning models (logistic regression, decision trees, SVM, KNN, random forest, and XGBoost) were trained with 10-fold cross-validation and hyperparameter tuning. Model performance was assessed with ROC curves, Decision Curve Analysis, and other metrics. The optimal model was integrated into an online risk assessment calculator.

Results

The XGBoost model showed the highest predictive performance, with key features including age, smoking, fall history, TDF use, HIV viral load, vitamin D, hemoglobin, albumin, CD4 count, and lumbar spine BMD. It achieved an ROC-AUC of 0.984 (95% CI: 0.977-0.99) in the training set and 0.979 (95% CI: 0.965-0.992) in the external test set. Decision Curve Analysis indicated clinical utility across various threshold probabilities, with calibration curves showing high concordance between predicted and observed risks. SHAP values explained individual risk profiles. The XGBoostpowered web calculator (https://sydtliubo.shinyapps.io/cls2shiny/) enables clinicians and patients to assess fragility fracture risk in PLWH.

Conclusion

We developed a web-based risk assessment tool using the XGBoost algorithm for predicting fragility fractures in HIV-positive patients. This tool, with its high accuracy and interpretability, aids in fracture risk stratification and management, potentially reducing the burden of fragility fractures in the HIV population.

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.

Cortical and Trabecular Bone Deficit in Middle-Aged Men Living with HIV

A significant increase in the risk of hip fracture was observed in middle-aged men living with human immunodeficiency virus (MLWH), almost a decade earlier than those without infection. Data regarding cortical and trabecular bone deficit of hip, an important determinant of bone strength, in MLWH are limited. Quantitative CT was performed in consecutive MLWH aged ≥30 years between November 2017 and October 2018 at Severance Hospital, Seoul, Korea. Volumetric bone mineral density (vBMD) and cortical bone mapping parameters of hip (cortical thickness [CTh], cortical bone vBMD [CBMD], cortical mass surface density [CMSD], endocortical trabecular density [ECTD]) were compared to age-matched and body mass index (BMI)-matched controls (1:2) using a community-based healthy adults cohort. Among 83 MLWH and 166 controls (mean age: 47.2 years; BMI: 23.6 kg/m2 ), MLWH had lower total hip vBMD (280 ± 41 versus 296 ± 41 mg/cm3 ), CMSD (155 versus 160 mg/cm2 ), and ECTD (158 versus 175 mg/cm3 ) than controls that remained robust after adjustment for covariates (adjusted β: total hip vBMD, -18.8; CMSD, -7.3; ECTD, -18.0; p < 0.05 for all). Cortical bone mapping revealed localized deficit of CTh, CBMD, and CMSD in the anterolateral trochanteric region and femoral neck in MLWH compared to controls, with a more extensive ECTD deficit. In MLWH, lower CD4 T-cell count (/100 cells/mm3 decrement) and protease inhibitor (PI)-based regimen (versus non-PI regimen) at the time of antiretroviral treatment initiation were associated with lower total hip vBMD (adjusted β -7.5 for lower CD4 count; -28.3 for PI-based regimen) and CMSD (adjusted β -2.6 for lower CD4 count; -12.7 for PI-based regimen; p < 0.05 for all) after adjustment for covariates including age, BMI, smoking, alcohol use, hepatitis C virus co-infection, tenofovir exposure, and CT scanner types. MLWH had lower hip bone density with cortical and trabecular bone deficit compared to community-dwelling controls. © 2023 American Society for Bone and Mineral Research (ASBMR).

Prevalence and predictors of low bone mineral density in treatment-naive HIV-infected patients and its correlation with CD4 cell counts

Objective:

HIV virtually affects every organ system of the body. The skeletal system is no exception, and antiretroviral therapy (ART) has been implicated in bone diseases. However, not many studies have been done to evaluate bone disease in treatment (ART) naive HIV-infected patients, and hence, the present study was executed.

Materials and Methods:

One hundred and twenty HIV-infected ART-naive patients and 80 age- and sex-matched healthy controls were recruited for this study. A thorough history and physical examination was done followed by laboratory investigations after an overnight fasting. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry scan at the level of lumbar spine, femur, and forearm.

Results:

Of 120 ART-naive HIV-infected cases, the prevalence of osteoporosis and osteopenia was 13% and 41%, respectively, as compared to 0% and 17.5% in controls (P < 0.001). The mean BMD in cases was 0.842 g/cm² which was approximately 25% lesser than that in controls. Hypovitaminosis-D was seen in 100% of cases as compared to 65% of controls (P < 0.01). A significant association of low BMD was seen with HIV-infection per se (P < 0.001), low CD4 cell counts (P < 0.001), low Vitamin D levels (P < 0.001), long duration of disease (P < 0.04), history of opportunistic infections (P < 0.03), and history of tuberculosis in the past (P < 0.05).

Conclusion:

Bone diseases such as osteoporosis and osteopenia characterized by low BMD are very common in HIV-infected patients. Virus per se, along with low CD4 cell counts and low Vitamin D levels are major predictors of pathological fractures in these individuals.

People living with HIV and fracture risk

PLHIV have an increased risk of osteoporosis and fractures when compared with people of the same age and sex. In this review, we address the epidemiology and the pathophysiology of bone disease and fractures in PLHIV. The assessment of fracture risk and fracture prevention in these subjects is also discussed. The spectrum of HIV-associated disease has changed dramatically since the introduction of potent antiretroviral drugs. Today, the survival of people living with HIV (PLHIV) is close to that of the general population. However, the longer life-span in PLHIV is accompanied by an increased prevalence of chronic diseases. Detrimental effects on bone health are well recognised, with an increased risk of osteoporosis and fractures, including vertebral fractures, compared to the general population. The causes of bone disease in PLHIV are not fully understood, but include HIV-specific risk factors such as use of antiretrovirals and the presence of chronic inflammation, as well as traditional risk factors for fracture. Current guidelines recommend the use of FRAX to assess fracture probability in PLHIV age ≥ 40 years and measurement of bone mineral density in those at increased fracture risk. Vitamin D deficiency, if present, should be treated. Bisphosphonates have been shown to increase bone density in PLHIV although fracture outcomes are not available.

Human immunodeficiency virus infection (HIV)-associated rheumatic manifestations in thepre- and post-HAART eras

Rheumatic manifestations remain an important clinical manifestation associated to HIV. To date after 4 decades of the onset of the HIV/AIDS pandemic, almost 37 million individuals are living with the infection, including close to 2 million of newly infected individuals. The status, however, of a considerable proportion of HIV/AIDS patients has changed from a near fatal disorder secondary to opportunistic infections to a chronic disease in which renal cardiovascular, diabetes, malignancy, and autoimmune co-morbid disorders have become prevalent and relevant. In addition, the spectrum of rheumatic disorders also has changed since the introduction of HAART and its diagnosis and treatment represents a challenge. The purpose of this review is to define and discuss the HIV-related rheumatic manifestations in the pre- and post-HAART eras.

Fractures Related to Tenofovir: A Case/Noncase Study in the European Pharmacovigilance Database

BACKGROUND

There is no clear consensus on the relationship between tenofovir (TDF) and fracture risk because the studies published so far present contradictory findings.

STUDY QUESTION

Our objective was to detect, from the European pharmacovigilance database (EudraVigilance), a signal of fracture risk during TDF exposure in patients infected with HIV.

METHODS

Herein, we analyze all the cases of fractures suspected to be related to TDF recorded in EudraVigilance between 2001 and November 10, 2016. A case/noncase method was used to assess the association between fractures and TDF, calculating proportional reporting ratios (PRRs) and their 95% confidence intervals (CIs) as a measure of disproportionality. According to the Medical Dictionary for Regulatory Activities (MedDRA) terminology, osteoporotic fractures are included in High Level Group Term (HLGT) "Fractures" and traumatic fractures in HLGT "Bone and joint injuries," so, we selected cases included in both HLGTs. The noncases used as controls were all the remaining adverse drug reaction reports recorded in EudraVigilance during the same period.

RESULTS

There were 68,113 cases of fractures in the 4,776,472 reports recorded in EudraVigilance during the study period. TDF was involved in 181 cases. The median latency period until the appearance of fracture was 995 days. TDF was present as the only suspect drug in 140 cases. The PRR of TDF and fractures was 1.11 (95% CI, 0.96-1.28). Nevertheless, disproportionality was observed for some types of fractures: osteoporotic fractures (PRR 17.24; 95% CI, 9.90-30.01), bone fissure (PRR 16.60; 95% CI, 6.11-45.10), and pathological fracture (PRR 4.40; 95% CI, 2.77-7.00).

CONCLUSIONS

Our findings do not show a disproportionality for fractures in patients treated with TDF, although disproportionality was found for some types of fractures, mainly osteoporotic fractures.

The management of treatment-experienced HIV patients (including virologic failure and switches)

Significant advances in the potency and tolerability of antiretroviral therapy (ART) have led to very high rates of virologic success for most who remain adherent to therapy. As a result, the life expectancy of people living with HIV (PLWH) has increased significantly. PLWH do, however, continue to experience a significantly higher risk of noninfectious comorbidities and chronic age-related complications, including cardiovascular disease and malignancies, which are now the biggest drivers of this excess morbidity and mortality. Therefore, in addition to virologic failure, the management of the treatment-experienced patient increasingly requires optimization of ART to enhance tolerability, avoid drug-drug interactions, and mitigate non-AIDS complications and comorbid conditions. This article will present principles of the management of virologic failure, poor immunologic recovery, and strategies for optimizing ART in the setting of virologic suppression.

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.

Impact of Estimated Pre-Exposure Prophylaxis (PrEP) Adherence Patterns on Bone Mineral Density in a Large PrEP Demonstration Project

Bone mineral density (BMD) declines due to tenofovir-containing pre-exposure prophylaxis (PrEP) have varied among PrEP demonstration projects, potentially related to variable adherence. Characterization of BMD changes in highly adherent individuals, estimated via tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS), can assist clinicians when counseling patients. Cisgender men who have sex with men and transwomen in the optional dual-energy X-ray absorptiometry (DXA) substudy of a large, international, open-label PrEP demonstration project, the iPrEx-open-label extension (OLE) study underwent DXA scans and DBS collection every 24 weeks, with average weekly dosing adherence patterns (2, 4, and 7 doses/week) estimated from validated TFV-DP cut-offs. The mean percent BMD change was estimated in strata of average weekly adherence by using a linear mixed-effects model to calculate the BMD decline in highly adherent individuals on PrEP for the first time. DXA/DBS data were available for 254 individuals over a median of 24 weeks in iPrEx-OLE from June 2011 to December 2013. The percent decline in spine BMD was monotonically associated with strata of increasing average weekly adherence (p < .001 trend); the p value for trends using hip BMD measurements was .07. Individuals with estimated daily adherence experienced a 1.2% decrease in spine BMD and a 0.5% drop in hip BMD. In highly adherent PrEP users, we found a lower-than-expected drop in BMD when compared with previous studies. This drop is likely not clinically significant for most PrEP users. However, for those at the highest risk of fracture who plan prolonged PrEP use, alternate PrEP strategies could be considered.

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.

Human Immunodeficiency Virus Infection: Spectrum of Rheumatic Manifestations

Emerging and reemerging viral infections have been a characteristic feature of the past several decades, with HIV infection being the most important example of an emergent viral infection. To date, the status of a considerable proportion of HIV/AIDS patients has changed from a near-fatal disorder secondary to opportunistic infections to a chronic disease in which a variety of co-morbid conditions have become prevalent and relevant. Arthralgia and myalgias are the most common symptoms. The rate of spondyloarthritis varies according to the geographic area, genetic and mode of transmission. Most RA and SLE patients might go into remission after the development of AIDS, but also there are patients that continue with active disease. Prevalence of DILS is highest among African Americans in less advanced stages. PAN is clinically less aggressive and peripheral neuropathy is the most common clinical manifestation. Anti-phospholipid syndrome (APS), systemic sclerosis and poly-dermatomyositis are uncommon. After the introduction of combination antiretroviral therapy (cART), a decline of spondyloarthritis disorders and of DILS and development of new syndromes such as IRIS, osteoporosis and avascular bone necrosis have occurred. The treatment of patients with rheumatic diseases and HIV infection remains a challenge.

The Hidden Burden of Fractures in People Living With HIV

The survival of people living with human immunodeficiency virus (HIV) has increased markedly since the advent of antiretroviral therapy (ART). However, other morbidities have emerged, including osteoporosis. The estimated incidence of fractures at any site in people living with HIV ranges from 0.1 per 1000 person‐years to 8.4 per 1000 person‐years: at least twice that of people without HIV. This increased risk seems to be related to HIV itself and its treatment. Risk factors for bone disease in HIV‐positive (HIV⁺) subjects include both classical risk factors for osteoporosis and fracture and factors linked to HIV itself, such as inflammation, reconstitution syndrome, low CD4, ART, and co‐infection with hepatitis B and C viruses. The risk of fractures in these individuals can be at least partially assessed by measurement of BMD and the Fracture Risk Assessment Tool (FRAX™). Only alendronate and zoledronic acid have been studied in HIV⁺ individuals; both show beneficial effects on BMD, although data on fracture reduction are not available. © 2018 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

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.

Tenofovir-Associated Bone Adverse Outcomes among a US National Historical Cohort of HIV-Infected Veterans: Risk Modification by Concomitant Antiretrovirals

Introduction

Tenofovir disoproxil fumarate (TDF) has been associated with greater incidences of bone complications, which might be modified by some concomitantly administered antiretrovirals, possibly by their effect on tenofovir concentrations. We compared bone adverse outcomes among treatment-naïve HIV-infected US veterans initiating efavirenz (EFV)-containing TDF/emtricitabine (FTC) regimens versus those initiating non-EFV-containing TDF/FTC regimens.

Methods

Using national Veterans Health Administration clinical and administrative data sets, we identified a cohort of treatment-naïve HIV-infected veterans without bone disease who initiated therapy with TDF/FTC plus EFV, rilpivirine, elvitegravir/cobicistat, or ritonavir-boosted protease inhibitors in 2003–2015. The primary composite adverse bone outcome was the unadjusted incidence rate (IR) of osteoporosis, osteopenia, or fragility fracture (any hip, wrist, or spine fracture). To account for selection bias and confounding, we used inverse probability of treatment-weighted Cox proportional hazards regression models to calculate adjusted hazard ratios (HRs) for each outcome associated with EFV + TDF/FTC versus each non-EFV-containing TDF/FTC regimen.

Results

Of 33,048 HIV-positive veterans, 7161 initiated a TDF/FTC-containing regimen (mean age, 50 years; baseline CD4 < 200 cells/mm³, 33.3%; HIV-1 RNA > 100,000 copies/ml, 22.3%; mean follow-up, 13.0 months). Of these, 4137 initiated EFV- and 3024 non-EFV-containing regimens. Veterans initiating EFV- versus non-EFV-containing TDF/FTC regimens had a lower IR of the composite bone outcome (29.3 vs. 41.4 per 1000 patient-years), with significant risk reductions for this outcome [HR, 0.69; 95% confidence interval (CI), 0.58–0.83] and fragility fracture (HR, 0.59; 95% CI, 0.44–0.78).

Conclusion

EFV + TDF/FTC is associated with a lower risk of adverse bone outcomes compared with other TDF-containing regimens in the VHA.

Funding

Bristol-Myers Squibb.

Electronic supplementary material

The online version of this article (10.1007/s40121-018-0194-1) contains supplementary material, which is available to authorized users.

Low bone mineral density among HIV-infected patients in Brazil

Decrease in bone mineral density (BMD) has been a complication among people living with HIV/AIDS. To investigate the prevalence of osteopenia/osteoporosis among HIV-infected people living in São Paulo city, we studied 108 HIV-infected patients (79 men and 29 women). We extracted data from patients’ medical records and BMD was measured by dual-energy X-ray absorptiometry (DXA). Median age of participants was 42 years (interquartile range [IQR] 36-48 years), and the median time since HIV diagnosis was 4.01 years (IQR 2-11 years). Patients had acquired HIV primarily by the sexual route (men who have sex with men 44%, heterosexual 49%). Median age, duration of HIV infection, duration of ART and CD4 nadir were similar for men and women. Plasma viral load was undetectable for 53 patients (49%). Median CD4 T cell count was 399 cells/µL (IQR 247 - 568). Twenty five patients (23%) had LBMD, and there was no statistically significant difference between men and women (<-1). The associated risk factors for LBMD were older age (≥ 50 years old) and smoking with a RR of 3.87 and 2.80, respectively. Thus, despite the lack of statistically significant relationship between the use of ART and LBMD or between duration of ART and LBMD, these factors should be addressed in larger studies.

Understanding mechanisms to promote successful aging in persons living with HIV

The mortality rate associated with HIV infection plummeted after the introduction of effective antiretroviral therapy pioneered two decades ago. As a result, HIV-infected people now have life expectancies comparable to that of HIV-uninfected individuals. Despite this, increased rates of osteoporosis, chronic liver disease, and in particular cardiovascular disease have been reported among people living with HIV infection. With the aging HIV-infected population, the burden of these comorbid illnesses may continue to accrue over time. In this paper, we present an overview of the aging HIV-infected population, its epidemiology and the many challenges faced. How to define and measure successful aging will also be reviewed. Finally, opportunities that may help mitigate the challenges identified and ensure successful aging among people living with HIV infection will be examined.

Brief Report: Recovery of Bone Mineral Density After Discontinuation of Tenofovir-Based HIV Pre-exposure Prophylaxis

BACKGROUND

Oral tenofovir disoproxil fumarate (TDF) for HIV prevention and treatment is associated with decreases in bone mineral density (BMD). Previous reports suggest that these changes may be reversible after discontinuation of TDF.

SETTING

A metabolic substudy of 498 participants in a randomized, placebo-controlled HIV prevention trial of oral coformulated TDF with emtricitabine (TDF/FTC, Truvada) for HIV pre-exposure prophylaxis (PrEP) enrolling a global sample of men who have sex with men and trans women.

METHODS

Participants underwent dual X-ray absorptiometry to quantify bone mineral density (BMD) in the hip and spine during PrEP and at 2 visits after stopping (median of 23 and 79 weeks post-PrEP, respectively). Results are stratified by pharmacologic measure of TDF/FTC adherence.

RESULTS

There was no significant difference in change in hip/spine BMD at any time point between placebo and those with low adherence. Adherent participants had a mean (standard error) BMD change at TDF/FTC discontinuation of -1.02% (0.24) in the hip and -1.84% (0.36) in the spine. After stop, annualized BMD increases of 1.13% per year (0.27) in hip and 1.81% per year (0.36) in spine BMD were observed in adherent participants compared with 0.19% (0.16) and 0.74% (0.21) in the placebo group, respectively (P = 0.003, both comparisons). On average, BMD returned to baseline levels by 1 year after PrEP stop. Recovery was consistent across age, baseline BMD z-score, and treatment duration.

CONCLUSIONS

Mean BMD returns to baseline levels within 12-18 months after TDF-based PrEP discontinuation in both hip and spine with consistency across participant subgroups.

CLINICAL TRIALS REGISTRATION

clinicaltrials.gov NCT00458393.

An increased rate of fracture occurs a decade earlier in HIV+ compared with HIV- men

OBJECTIVES

To determine the incidence of fracture among aging HIV-infected (HIV+) and uninfected men (HIV-). To evaluate factors independently associated with fracture risk.

DESIGN

Prospective, multicenter cohort study of men with or at risk for HIV.

METHODS

Outcome measures: all fractures (excluding skull, face and digits) and fragility fractures (vertebral column, femur, wrist and humerus) were collected semiannually in 1221 HIV+ and 1408 HIV- men aged at least 40. Adjusted incident rate ratios (aIRR) with an interaction term for age (40-49, 50-59 and ≥60 years) and HIV serostatus were estimated with Poisson regression models accounting for additional risk factors.

RESULTS

Fracture incidence increased with age among both HIV+ and HIV- men. Although there was no significant difference in fracture incidence by HIV serostatus among men aged 40-49 years, the HIV+ men aged 50-59 years had a significantly higher incidence of all fractures [aIRR: 2.06 (1.49, 2.84)] and fragility fractures [aIRR: 2.06 (1.21, 3.50)] compared with HIV- participants of similar age. HIV modified the effect of age on all fractures (P = 0.002) but did not significantly modify the effect for fragility fractures (P = 0.135). Hypertension increased the rate of all fractures by 32% after adjustment for covariates [aIRR: 1.32 (1.04, 1.69)].

CONCLUSION

Fracture incidence increased with age among HIV+ and HIV- men but was higher among HIV+ men. A significant increase in fracture incidence was found among 50-59-year-old HIV+ men, highlighting the importance of osteoporosis screening for HIV-infected men above the age of 50.

Administration of an activin receptor IIB ligand trap protects male juvenile rhesus macaques from simian immunodeficiency virus-associated bone loss

HIV-infected individuals are at an increased risk of osteoporosis despite effective viral suppression. Observations that myostatin null mice have increased bone mass led us to hypothesize that simian immunodeficiency virus (SIV)-associated bone loss may be attenuated by blocking myostatin/TGFβ signaling. In this proof-of-concept study, pair-housed juvenile male rhesus macaques were inoculated with SIVmac239. Four weeks later, animals were treated with vehicle or Fc-conjugated soluble activin receptor IIB (ActR2B·Fc, iv. 10mg∗kg^-1∗week^-1) - an antagonist of myostatin and related members of TGFβ superfamily. Limb and trunk bone mineral content (BMC) and density (BMD) using dual-energy X-Ray absorptiometry, circulating markers of bone growth and turnover, and serum testosterone levels were measured at baseline and during the 12-week intervention period. The increase in BMC was significantly greater in the ActRIIB.Fc-treated group (+8g) than in the placebo group (-4g) (p<0.05). BMD also increased significantly more in the ActRIIB.Fc-treated macaques (+0.03g/cm²) than in the placebo-treated animals (+0g/cm²) (p<0.005). Serum osteocalcin was about two-fold higher in the ActRIIB.Fc-treated group than in the placebo group (p<0.05), but serum C-terminal telopeptide and testosterone levels did not differ significantly between groups. The expression levels of TNFalpha (p<0.05), GADD45 (p<0.005), and sclerostin (p<0.038) in the bone-marrow were significantly lower in the ActRIIB.Fc-treated group than in the placebo group.

CONCLUSION

The administration of ActRIIB.FC in SIV-infected juvenile macaques significantly increases BMC and BMD in association with reduced expression levels of markers of bone marrow inflammation.

Impaired Upregulation of the Costimulatory Molecules, CD27 and CD28, on CD4+ T Cells from HIV Patients Receiving ART Is Associated with Poor Proliferative Responses

HIV patients beginning antiretroviral therapy (ART) with advanced immunodeficiency often retain low CD4⁺ T cell counts despite virological control. We examined proliferative responses and upregulation of costimulatory molecules, following anti-CD3 stimulation, in HIV patients with persistent CD4⁺ T cell deficiency on ART. Aviremic HIV patients with nadir CD4⁺ T cell counts <100 cells/μL and who had received ART for a median time of 7 (range 1-11) years were categorized into those achieving low (<350 cells/μL; n = 13) or normal (>500 cells/μL; n = 20) CD4⁺ T cell counts. Ten healthy controls were also recruited. CD4⁺ T cell proliferation (Ki67) and upregulation of costimulatory molecules (CD27 and CD28) after anti-CD3 stimulation were assessed by flow cytometry. Results were related to proportions of CD4⁺ T cells expressing markers of T cell senescence (CD57), activation (HLA-DR), and apoptotic potential (Fas). Expression of CD27 and/or CD28 on uncultured CD4⁺ T cells was similar in patients with normal CD4⁺ T cell counts and healthy controls, but lower in patients with low CD4⁺ T cell counts. Proportions of CD4⁺ T cells expressing CD27 and/or CD28 correlated inversely with CD4⁺ T cell expression of CD57, HLA-DR, and Fas. After anti-CD3 stimulation, induction of CD27^hiCD28^hi expression was independent of CD4⁺ T cell counts, but lower in HIV patients than in healthy controls. Induction of CD27^hiCD28^hi expression correlated with induction of Ki67 expression in total, naïve, and CD31⁺ naïve CD4⁺ T cells from patients. In HIV patients responding to ART, impaired induction of CD27 and CD28 on CD4⁺ T cells after stimulation with anti-CD3 is associated with poor proliferative responses as well as greater CD4⁺ T cell activation and immunosenescence.

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.

Tenofovir and bone health

PURPOSE OF REVIEW

With continued improvements to the antiviral efficacy and tolerability of antiretroviral therapy, long-term safety of antiretroviral therapy has become paramount. Low bone mineral density and fragility fractures are more common in HIV-infected individuals than in the general population. The aims of this review are to describe potential mechanisms underlying the adverse effects of tenofovir on bone, clinical studies of tenofovir disoproxil fumarate (TDF) and bone, and more recent bone data on tenofovir alafenamide.

RECENT FINDING

Several studies have demonstrated an approximately 1-3% greater bone mineral density loss with TDF compared with other agents. Recent studies with tenofovir alafenamide have shown improved bone (and renal) safety with similar virologic efficacy when compared to TDF.

SUMMARY

Given these findings, TDF-containing regimens may be gradually replaced with non-TDF containing regimens for the treatment of HIV infection, especially in those at higher risk for fragility fracture.

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.

Does systemic inflammation and immune activation contribute to fracture risk in HIV?

PURPOSE OF REVIEW

There is increasing evidence pointing toward an important role of heightened immune activation and inflammation in people living with HIV contributing to the development of non-AIDS comorbidities. This review aims to explore low bone mineral density (BMD) in HIV with a focus on the underlying mechanisms and relationships between the immune and skeletal systems.

RECENT FINDINGS

Baseline immune activation and inflammation negatively impact BMD at antiretroviral therapy (ART) initiation. B- and T-cell alterations in HIV lead to an imbalance in the osteoblastic osteoprotegerin (OPG) and osteoclastic receptor activator of NF-κB ligand (RANKL) cytokines which favours osteoclastogenesis and bone resorption. These findings suggest an important role for immune-mediated mechanisms in the pathogenesis of low BMD in HIV.

SUMMARY

Bone homeostasis is in part regulated by cells of the immune system through complex interactions with the RANK/RANKL/OPG axis. Disturbances in the normal functioning of T, B cells, and monocytes in HIV and the resulting proinflammatory state may contribute to dysregulation of this finely controlled balance leading to increased bone loss. Pre-ART levels of immune activation and inflammation have a consistently negative effect on BMD and further suggest the immunocentric basis of bone loss in HIV alongside supporting the benefits of earlier ART initiation. Further longitudinal studies will help determine the effect this will have on fracture risk in people living with HIV.

Responsiveness to IL-7 but not to IFN-α is diminished in CD4+ T cells from treated HIV infected patients who experience poor CD4+ T-cell recovery

OBJECTIVE

To assess CD4 T-cell responsiveness to IL-7 and IFN-α in HIV-infected patients who experience poor recovery of CD4 T-cell counts during therapy (immune failure patients).

DESIGN

Responses to IL-7 and IFN-α were compared between HIV-infected immune failure (CD4 cell counts <379 cells/μl) patients and immune success (CD4 cell counts >500 cells/μl) as well as healthy control patients.

METHODS

Flow cytometry was used to assess peripheral blood mononuclear cells for IL-7-induced proliferation, CD25 expression, and signaling (signal transducer and activator of transcription 5 phosphorylation and Akt phosphorylation) in CD4 T cells. Freshly isolated cells were characterized by expression of IL-7Rα (CD127) among CD4 T-cell maturation subsets by flow cytometry and sorted CD3 T cells were assessed for expression of IFN-α and interferon stimulated genes (2'-5'-oligoadenylate synthetase-1 and myxovirus resistance A protein) by quantitative real-time PCR. Responses to IFN-α were assessed by induction of signal transducer and activator of transcription 1 phosphorylation and inhibition of IL-7-induced CD4 T-cell proliferation.

RESULTS

IL-7-induced proliferation and CD25 expression were decreased in CD4 T cells from immune failure patients. CD127 expressing CD4 T cells were decreased, whereas expression of 2'-5'-oligoadenylate synthetase-1, myxovirus resistance A protein, and IFN-α mRNA were increased in total CD3 T cells from immune failure patients. CD127 expression correlated with CD25 induction but not proliferation, whereas T-cell IFN-α mRNA was associated with reduced proliferation in CD4 T cells from immune failure patients. IFN-α-mediated induction of signal transducer and activator of transcription 1 phosphorylation and inhibition of proliferation were not diminished in CD4 T cells from immune failure patients.

CONCLUSION

IL-7 responsiveness is impaired in immune failure patients and may be related to expression of CD127 and IFN-α.

Serum Sclerostin Levels in Patients with Human Immunodeficiency Virus Infection and Their Association with Bone Turnover Markers and Bone Mineral Densitometry

Background

The aim of the study was to compare serum sclerostin levels in human im-munodeficiency virus (HIV)-infected patients and healthy controls, and to evaluate their relationship with bone turnover markers (BTM) and bone mineral density (BMD).

Methods

We prospectively studied 33 HIV treatment-naive patients and 63 healthy individuals; matched for age and sex. Serum sclerostin levels, BTM, BMD were measured. Viral load and cluster of differentiation 4 (CD4) levels were also assessed in HIV-infected patients.

Results

The mean±standard deviation (SD) age of sample was 37.6±10.3 years (range, 19 to 59 years). Of the 96 subjects, 58 (60.4%) were male and 38 (39.6%) were female. Infection with HIV is associated with significant reduction in serum sclerostin levels (HIV-infected: 39.4±28.3 vs. non HIV: 76.6±15.7 pmol/L; P<0.001) and a decrease in BMD at femoral neck and lumbar spine compared to healthy controls. Sclerostin however was not correlated with BMD and was not related to age, generally a strong correlation. There were no significant correlations between sclerostin and BTM (P>0.05).

Conclusions

These findings suggest that untreated HIV and the resulting immune deficiency and/or systemic inflammation could be an important regulator of serum sclerostin in this population.

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.

Chest Low-Dose Computed Tomography for Early Lung Cancer Diagnosis as an Opportunity to Diagnose Vertebral Fractures in HIV-Infected Smokers, an ANRS EP48 HIV CHEST Substudy

BACKGROUND

To estimate the prevalence of vertebral fractures on chest low-dose computed tomography (LDCT) in HIV-infected smokers.

METHODS

Cross-sectional study of vertebral fractures visualized on chest LDCT from a multicenter prospective cohort evaluating feasibility of chest LDCT for early lung cancer diagnosis in HIV-infected subjects. Subjects were included if 40 years or older, had been active smokers within the last 3 years of at least 20 pack-years, and had a CD4 T-lymphocyte nadir cell count <350 per microliter and an actual CD4 T-cell count >100 cells per microliter. Spinal reconstructed sagittal planes obtained from chest axial native acquisitions were blindly read by a musculoskeletal imaging specialist. Assessment of the fractured vertebra used Genant semiquantitative method. The study end point was the prevalence of at least 1 vertebral fracture.

RESULTS

Three hundred ninety-seven subjects were included. Median age was 49.5 years, median smoking history was 30 pack-years, median last CD4 count was 584 cells per microliter, and median CD4 nadir count was 168 cells per microliter; 90% of subjects had a viral load below 50 copies per milliliter. At least 1 fracture was visible in 46 (11.6%) subjects. In multivariate analysis, smoking ≥40 packs-years [OR = 2.5; 95% CI: (1.2 to 5.0)] was associated with an increased risk of vertebral fracture, while HIV viral load <200 copies per milliliter [OR = 0.3; 95% CI: (0.1 to 0.9)] was protective.

CONCLUSIONS

Prevalence of vertebral fractures on chest LDCT was 11.6% in this high-risk population. Smoking cessation and early introduction of antiretroviral therapy for prevention of vertebral fractures could be beneficial. Chest LDCT is an opportunity to diagnose vertebral fractures.

Thirty-day hospital readmissions for adults with and without HIV infection

OBJECTIVES

Risk-adjusted 30-day hospital readmission rate is a commonly used benchmark for hospital quality of care and for Medicare reimbursement. Persons living with HIV (PLWH) may have high readmission rates. This study compared 30-day readmission rates by HIV status in a multi-state sample with planned subgroup comparisons by insurance and diagnostic categories.

METHODS

Data for all acute care, nonmilitary hospitalizations in nine states in 2011 were obtained from the Healthcare Costs and Utilization Project. The primary outcome was readmission for any cause within 30 days of hospital discharge. Factors associated with readmission were evaluated using multivariate logistic regression.

RESULTS

A total of 5 484 245 persons, including 33 556 (0.6%) PLWH, had a total of 6 441 695 index hospitalizations, including 45 382 (0.7%) among PLWH. Unadjusted readmission rates for hospitalizations of HIV-uninfected persons and PLWH were 11.2% [95% confidence interval (CI) 11.2, 11.2%] and 19.7% (95% CI 19.3, 20.0%), respectively. After adjustment for age, gender, race, insurance, and diagnostic category, HIV infection was associated with 1.50 (95% CI 1.46, 1.54) times higher odds of readmission. Predicted, adjusted readmission rates were higher for PLWH within every insurance category, including Medicaid [12.9% (95% CI 12.8, 13.0%) and 19.1% (95% CI 18.4, 19.7%) for HIV-uninfected persons and PLWH, respectively] and Medicare [13.2% (95% CI 13.1, 13.3%) and 18.0% (95% CI 17.4, 18.7%), respectively], and within every diagnostic category.

CONCLUSIONS

HIV infection is associated with significantly increased readmission risk independent of demographics, insurance, and diagnostic category. The 19.7% 30-day readmission rate may serve as a preliminary benchmark for assessing quality of care of PLWH. Policy-makers may consider adjusting for HIV infection when calculating a hospital's expected readmission rate.

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.

Update on the key developments of the neurologic complications in children infected with HIV

PURPOSE OF REVIEW

To discuss recent research findings of neurologic complications in HIV-infected children, specifically addressing neuroinfections, cerebrovascular disease, epilepsy and neurocognitive complications. The range of neurologic childhood onset complications is diverse and often overlaps diseases previously considered only to manifest in adults. In the pediatric population, these complications frequently have their own unique disease identity, which may be related to maturational patterns evident in the developing brain.

RECENT FINDINGS

Developments regarding the pathogenesis of neuroAIDS, treatment of tuberculous meningitis and prevention of bacterial meningitis are described. With the advent of neuroimaging, there is greater insight into silent cerebrovascular events and the progression of vasculopathy in HIV-infected children. The role of surgical intervention for affected cases is a novel area that could alter the otherwise poor prognosis. Epilepsy, although common as a burden of disease, carries its own additional complications with regard to cross reactivity with various antiretroviral therapies. Increased risk of low bone mineral density supports a role for supplementation with vitamin D in people receiving antiretroviral therapy and antiepileptic drugs. Recognition of the early neurobiological, as well as spectrum of neurocognitive effects of the HIV on the developing brain, is evolving, as greater numbers of children are treated early. Developments in these critical areas are described.

SUMMARY

Recent research reflects the need for improved strategies to prevent neuroinfections, more effective screening and interventions for vasculopathy and better antiepileptic drugs for HIV-infected children. Furthermore, our understanding of the timing and spectrum of neurocognitive complications is evolving.

Effects of Emtricitabine/Tenofovir on Bone Mineral Density in HIV-Negative Persons in a Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Daily preexposure prophylaxis (PrEP) with oral emtricitabine and tenofovir disoproxil fumarate (FTC/TDF) decreases the risk of human immunodeficiency virus (HIV) acquisition. Initiation of TDF decreases bone mineral density (BMD) in HIV-infected people. We report the effect of FTC/TDF on BMD in HIV-seronegative men who have sex with men and in transgender women.

METHODS

Dual-energy X-ray absorptiometry was performed at baseline and 24-week intervals in a substudy of iPrEx, a randomized, double-blind, placebo-controlled trial of FTC/TDF PrEP. Plasma and intracellular tenofovir concentrations were measured in participants randomized to FTC/TDF.

RESULTS

In 498 participants (247 FTC/TDF, 251 placebo), BMD in those randomized to FTC/TDF decreased modestly but statistically significantly by 24 weeks in the spine (net difference, -0.91% [95% confidence interval {CI}, -1.44% to -.38%]; P = .001) and hip (-0.61% [95% CI, -.96% to -.27%], P = .001). Changes within each subsequent 24-week interval were not statistically significant. Changes in BMD by week 24 correlated inversely with intracellular tenofovir diphosphate (TFV-DP), which was detected in 53% of those randomized to FTC/TDF. Net BMD loss by week 24 in participants with TFV-DP levels indicative of consistent dosing averaged -1.42% ± 29% and -0.85% ± 19% in the spine and hip, respectively (P < .001 vs placebo). Spine BMD tended to rebound following discontinuation of FTC/TDF. There were no differences in fractures (P = .62) or incidence of low BMD.

CONCLUSIONS

In HIV-uninfected persons, FTC/TDF PrEP was associated with small but statistically significant decreases in BMD by week 24 that inversely correlated with TFV-DP, with more stable BMD thereafter.

CLINICAL TRIALS REGISTRATION

NCT00458393.

Skeletal health in adults with HIV infection

Concern has been raised that HIV infection, its treatment, or both adversely affect skeletal health. Cross-sectional studies show that bone mineral density (BMD) is 3-5% lower in patients infected with HIV than in uninfected controls, but patients with HIV infection are, on average, 5 kg lighter than uninfected people. After this weight difference is accounted for, BMD differences are smaller and not clinically relevant. Longitudinal studies show short-term BMD loss of 2-4% over 1-2 years when antiretroviral therapy is started, followed by longer periods of BMD increase or stability. Losses are greatest with treatment regimens that contain tenofovir. Patients infected with HIV have slightly higher fracture rates than controls, but the increased risk of fracture is substantially attenuated by adjustment for traditional risk factors for fracture. These reassuring findings suggest that management of skeletal health in HIV should follow guidelines for the general population. In general, effective antiretroviral treatment and avoidance of undernutrition are the two most important factors for maintenance of skeletal health in patients infected with HIV.

Inflammatory co-morbidities in HIV+ individuals: learning lessons from healthy ageing

Increased life expectancy due to improved efficacy of cART has uncovered an increased risk of age-related morbidities in HIV+ individuals and catalyzed significant research into mechanisms driving these diseases. HIV infection increases the risk of non-communicable diseases common in the aged, including cardiovascular disease, neurocognitive decline, non-AIDS malignancies, osteoporosis, and frailty. These observations suggest that HIV accelerates immunological ageing, and there are many immunological similarities with the aged, including shortened telomeres, accumulation of senescent T cells and altered monocyte phenotype/function. However, the most critical similarity between HIV+ individuals and the elderly, which most likely underpins the heightened risk of non-communicable diseases, is chronic inflammation and associated immune activation. Here, we review the similarities between HIV+ individuals and the aged regarding the pathogenesis of inflammatory diseases, the current evidence for mechanisms driving these processes and discuss current and potential therapeutic strategies for addressing inflammatory co-morbidity in HIV+ infection.

Proton pump inhibitors and risk of bone fractures

OPINION STATEMENT

There are 34 studies in almost 2 million participants that have reported on the association between proton pump inhibitor (PPI) therapy and risk of fracture. There is substantial variation between the results of each study but systematic reviews of the data suggest overall there is an association between PPI therapy and risk of fracture. The magnitude of the association is modest and is most likely due to confounding factors as patients prescribed PPI therapy tend to be more frail with more risk factors for fractures than those not given these drugs. There is no clear dose-response relationship and there is no association between PPI therapy and risk of fracture in those at highest risk. Finally, there is no clear mechanism through which PPI therapy increases the risk of fracture, as recent randomized trials show no impact of PPI therapy on calcium absorption and there is no association between PPI therapy and risk of osteoporosis. We therefore feel there is insufficient evidence to change PPI prescribing habits based on risk of fracture. Similarly, we do not recommend bone mineral density investigations for patients taking PPI therapy other than would be normally indicated. There is no evidence to support prescription of calcium and/or vitamin D in patients simply because they are taking PPI therapy. As with all medications, we only recommend prescribing PPI therapy when there is a clear indication that benefit will outweigh risk and at the lowest effective dose. Patients should be regularly assessed as to whether acid suppression is still required.

Osteoporosis and fracture risk associated with HIV infection and treatment

Osteoporosis has emerged as an important co-morbidity of HIV infection and a modest increase in fracture risk has been documented. Bone loss from the spine and hip occurs after initiation of antiretroviral therapy but most data indicate that bone mineral density is stable in HIV-infected individuals established on long-term antiretroviral therapy. Assessment of fracture probability should be performed in individuals who have clinical risk factors for fracture. Adequate dietary calcium intake and vitamin D status should be ensured and in individuals with a high fracture probability, bisphosphonate therapy may be appropriate.

IFN-α exerts opposing effects on activation-induced and IL-7-induced proliferation of T cells that may impair homeostatic maintenance of CD4+ T cell numbers in treated HIV infection

To determine whether IFN-α is a cause of the T cell hyperactivation and IL-7 signaling pathway defects that are observed in some HIV patients receiving antiretroviral therapy, we have investigated the effect of IFN-α on the proliferation of CD4(+) and CD8(+) T cells from healthy donors (n = 30) and treated HIV(+) donors (n = 20). PBMC were cultured for 7 d with staphylococcal enterotoxin B or IL-7 in the absence or presence of 100 U/ml IFN-α8. Total and naive CD4(+) and CD8(+) T cells were assessed for proliferation (via Ki67 expression), CD127 expression, and phosphorylated STAT5 levels using flow cytometry. IFN-α significantly enhanced activation-induced proliferation (via staphylococcal enterotoxin B stimulation) but inhibited homeostatic proliferation (IL-7 induced) of CD4(+) and CD8(+) T cells. Both of these effects may adversely affect CD4(+) T cell homeostasis in HIV patients. CD127 expression was increased in both healthy and HIV(+) donors following culture with IFN-α8, and levels of IL-7-induced phosphorylated STAT5 were increased by IFN-α8 in healthy donors only. Hence, the inhibitory effects of IFN-α on IL-7-induced proliferation of CD4(+) T cells are unlikely to be mediated by downregulation of CD127 expression or inhibition of STAT5 phosphorylation. These data suggest that increased IFN-α activity may promote the loss of T cells by accelerating cell turnover and activation-induced cell death while decreasing the renewal of T cells by inhibiting the proliferative effect of IL-7.

The effect of HIV-hepatitis C co-infection on bone mineral density and fracture: a meta-analysis

OBJECTIVE

There is a variable body of evidence on adverse bone outcomes in HIV patients co-infected with hepatitis C virus (HCV). We examined the association of HIV/HCV co-infection on osteoporosis or osteopenia (reduced bone mineral density; BMD) and fracture.

DESIGN

Systematic review and random effects meta-analyses.

METHODS

A systematic literature search was conducted for articles published in English up to 1 April 2013. All studies reporting either BMD (g/cm2, or as a T-score) or incident fractures in HIV/HCV co-infected patients compared to either HIV mono-infected or HIV/HCV uninfected/seronegative controls were included. Random effects meta-analyses estimated the pooled odds ratio (OR) and the relative risk (RR) and associated 95% confidence intervals (CI).

RESULTS

Thirteen eligible publications (BMD N = 6; Fracture = 7) of 2,064 identified were included with a total of 427,352 subjects. No publications reported data on HCV mono-infected controls. Meta-analysis of cross-sectional studies confirmed that low bone mineral density was increasingly prevalent among co-infected patients compared to HIV mono-infected controls (pooled OR 1.98, 95% CI 1.18, 3.31) but not those uninfected (pooled OR 1.47, 95% CI 0.78, 2.78). Significant association between co-infection and fracture was found compared to HIV mono-infected from cohort and case-control studies (pooled RR 1.57, 95% CI 1.33, 1.86) and compared to HIV/HCV uninfected from cohort (pooled RR 2.46, 95% CI 1.03, 3.88) and cross-sectional studies (pooled OR 2.30, 95% CI 2.09, 2.23).

CONCLUSIONS

The associations of co-infection with prevalent low BMD and risk of fracture are confirmed in this meta-analysis. Although the mechanisms of HIV/HCV co-infection's effect on BMD and fracture are not well understood, there is evidence to suggest that adverse outcomes among HIV/HCV co-infected patients are substantial.

The effects of untreated and treated HIV infection on bone disease

PURPOSE OF REVIEW

Low bone mineral density (BMD) is common in those with HIV, associated with higher bone turnover and a higher prevalence of fractures. This review explores low BMD in HIV, focusing on underlying mechanisms and relationships between low BMD and HIV infection, immune dysfunction, and antiretroviral therapy (ART).

RECENT FINDINGS

Greater reductions in BMD accompanying reductions in HIV viremia at initiation of first-line or second-line ART suggest an important role for immune- or viral-mediated mechanisms in its pathogenesis.

SUMMARY

As bone metabolism is part-regulated by T cells and B cells, we propose that earlier initiation of ART at higher CD4 T-cell counts may attenuate BMD loss by abrogating immune- and viral-mediated disturbances in bone metabolism that accompany ART initiation. Further pathogenesis-based research is required in this field, focusing on the complex interaction between virus, immune system, ART, and bone metabolism.

HIV infection, bone metabolism, and fractures

With the advent of high active antiretroviral therapy there was a significant improvement on HIV subjects survival. Thus, bone changes related to HIV became an important aspect of these individuals. HIV affects bone remodeling causing bone fragility. In addition, antiretroviral therapy may also negatively affect bone metabolism. Several studies describe an increased incidence of fractures in these patients when compared with controls without the disease. The European Society of AIDS (EACS), and other societies, have included guidance on management of osteoporosis in HIV-infected patients emphasizing the identification of patients with low bone mass. Supplementation of calcium and vitamin D and the use of alendronate in these individuals should be recommended on a case base.

Interleukin-7 signalling defects in naive CD4+ T cells of HIV patients with CD4+ T-cell deficiency on antiretroviral therapy are associated with T-cell activation and senescence

OBJECTIVE

To examine the relationship of defects in interleukin (IL)-7-induced naive CD4 T-cell homeostasis with residual immune activation and CD4 T-cell senescence in HIV patients receiving antiretroviral therapy (ART) who exhibit persistent CD4 T-cell deficiency.

DESIGN

IL-7 induced proliferation of, and IL-7 receptor signalling in, total and naive CD4 T cells of HIV patients who had low (<350 cells/μl) or normal (>500 cells/μl) CD4 T-cell counts on ART was examined and related to markers of CD4 T-cell activation and senescence and innate immune activation.

METHODS

Total, naive (CD45RA CD27) and CD31 naive CD4 T cells from aviremic HIV patients (n=39) with nadir CD4 T-cell counts less than 100 cells/μl, who had received ART for a median time of 7 (range 1-11) years, were assessed for CD127 expression, proliferation (Ki67), signal transducer and activator of transcription 5 phosphorylation (pSTAT5) and CD127 modulation following IL-7 stimulation. Changes were related to proportions of CD4 T cells expressing HLA-DR or CD57 and plasma levels of sCD14, CXCL9 and CXCL10.

RESULTS

Patients with CD4 T-cell deficiency exhibited lower expression of CD127 on total, naive and CD31 naive CD4 T cells. Downregulation of CD127 after culture with IL-7 correlated inversely with CD4 T-cell counts and directly with Ki67 expression. Induction of pSTAT5 in CD4 T-cell subsets was greater in patients with normal CD4 T-cell counts. CD127 expression correlated inversely with proportions of CD4CD57 T cells, and pSTAT5 induction correlated inversely with CD4 T-cell expression of HLA-DR and CD57.

CONCLUSION

Defects of IL-7 signalling in HIV patients with persistent CD4 T-cell deficiency receiving ART are associated with CD4 T-cell activation and senescence.

Osteoporosis in Human Immunodeficiency Virus Patients - An Emerging Clinical Concern

The advent of highly active anti-retroviral therapy (HAART) has significantly improved the survival of human immunodeficiency virus (HIV)-infected patients transforming the HIV infection from a fatal illness into a manageable chronic disease. As the number of older HIV-infected individuals increases, several ageing-related co-morbidities including osteopenia/osteoporosis and fractures have emerged. Patients exposed to HIV infection and its treatment may develop fragility fractures with potential significant impact on quality of life and survival. However, the awareness of HIV-related skeletal fragility is still relatively low and most HIV-infected patients are not investigated for osteoporosis and treated with anti-osteoporotic drugs in daily clinical practice. This article reviews the literature data on osteoporosis and osteopenia in HIV infection, focusing on the pathophysiological, clinical and therapeutic aspects of fragility fractures.

Bone mineral density effects of randomized regimen and nucleoside reverse transcriptase inhibitor selection from ACTG A5142

OBJECTIVE

To compare the longitudinal changes in total bone mineral density (TBMD) across antiretroviral (ARV) regimens.

METHODS

A5142 was an open-label study comparing 3 ARV regimens for the initial treatment of HIV-1. Subjects were randomized equally to efavirenz (EFV) plus 2 nucleoside reverse transcriptase inhibitors (NRTIs), lopinavir/ritonavir (LPV/r) plus 2 NRTIs, or LPV/r plus EFV without NRTI. The NRTI regimen (lamivudine [3TC] plus zidovudine [ZDV], stavudine [d4T], or tenofovir [TDF]) was selected prior to randomization. TBMD was assessed via whole-body dual-energy X-ray absorptiometry (DXA) at baseline and 48 and 96 weeks. Analysis was modified intent-to-treat (ITT) ignoring regimen changes using all evaluations.

RESULTS

Significant mean declines in TBMD at week 48 were observed among subjects. In repeated-measures analysis of changes (including randomized regimen, NRTI used, and time), there was a significant difference in the NRTI-containing arms in mean percentage change in TBMD at week 48 according to NRTI used (P < .001). Subjects taking ZDV had similar changes to those taking d4T (P = .970), whereas those taking TDF had larger declines (P < .001). There was a nonsignificant trend toward greater mean declines among subjects taking LPV/r versus EFV (P = .080). Overall, TDF-containing regimens demonstrated the greatest losses in TBMD, while EFV regimens without TDF had lesser TBMD reductions even compared to the NRTI-sparing arm. From week 48 to 96, all treatment groups continued to lose TBMD at similar rates.

CONCLUSIONS

Among NRTI-containing arms, NRTI selection, especially use of TDF, had a greater effect on TBMD change than randomized regimen. The long-term clinical significance remains to be demonstrated.

[Consensus Statement by GeSIDA/National AIDS Plan Secretariat on antiretroviral treatment in adults infected by the human immunodeficiency virus (Updated January 2013)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the GeSIDA/National AIDS Plan Secretariat (Grupo de Estudio de Sida and the Secretaría del Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations and the evidence which support them are based on a modification of the criteria of Infectious Diseases Society of America.

RESULTS

cART is recommended in patients with symptoms of HIV infection, in pregnant women, in serodiscordant couples with high risk of transmission, in hepatitisB co-infection requiring treatment, and in HIV nephropathy. cART is recommended in asymptomatic patients if CD4 is <500cells/μl. If CD4 are >500cells/μl cART should be considered in the case of chronic hepatitisC, cirrhosis, high cardiovascular risk, plasma viral load >100.000 copies/ml, proportion of CD4 cells <14%, neurocognitive deficits, and in people aged >55years. The objective of cART is to achieve an undetectable viral load. The first cART should include 2 reverse transcriptase inhibitors (RTI) nucleoside analogs and a third drug (a non-analog RTI, a ritonavir boosted protease inhibitor, or an integrase inhibitor). The panel has consensually selected some drug combinations, for the first cART and specific criteria for cART in acute HIV infection, in tuberculosis and other HIV related opportunistic infections, for the women and in pregnancy, in hepatitisB or C co-infection, in HIV-2 infection, and in post-exposure prophylaxis.

CONCLUSIONS

These new guidelines update previous recommendations related to first cART (when to begin and what drugs should be used), how to monitor, and what to do in case of viral failure or adverse drug reactions. cART specific criteria in comorbid patients and special situations are similarly updated.

Residual immune dysregulation syndrome in treated HIV infection

Antiretroviral therapy has revolutionized the course of HIV infection, improving immune function and decreasing dramatically the mortality and morbidity due to the opportunistic complications of the disease. Nonetheless, even with sustained suppression of HIV replication, many HIV-infected persons experience a syndrome characterized by increased T cell activation and evidence of heightened inflammation and coagulation. This residual immune dysregulation syndrome or RIDS is more common in persons who fail to increase circulating CD4+ T cells to normal levels and in several epidemiologic studies it has been associated with increased morbidity and mortality. These morbid and fatal events are not the typical opportunistic infections and malignancies seen in the early AIDS era but rather comprise a spectrum of cardiovascular events, liver disease, metabolic disorders, kidney disease, bone disease, and a spectrum of malignant complications distinguishable from the opportunistic malignancies that characterized the earlier days of the AIDS epidemic. While immune activation, inflammation, and coagulopathy are characteristic of untreated HIV infection and improve with drug-induced control of HIV replication, the drivers of RIDS in treated HIV infection are incompletely understood. And while inflammation, immune activation, and coagulopathy are more common in treated persons who fail to restore circulating CD4+ T cells, it is not entirely clear how these two phenomena are linked.