Fracture incidence in HIV-infected women: results from the Women's Interagency HIV Study

Effects of smoking on non-AIDS-related morbidity in HIV-infected patients

Tobacco smoking has many adverse health consequences. Patients with human immunodeficiency virus (HIV) infection smoke at very high rates, and many of the comorbidities associated with smoking in the general population are more prevalent in this population. It is likely that a combination of higher smoking rates along with an altered response to cigarette smoke throughout the body in persons with HIV infection leads to increased rates of the known conditions related to smoking. Several AIDS-defining conditions associated with smoking have been reviewed elsewhere. This review aims to summarize the data on non-AIDS-related health consequences of smoking in the HIV-infected population and explore evidence for the potential compounding effects on chronic systemic inflammation due to HIV infection and smoking.

The Role of Inflammatory Cytokines, the RANKL/OPG Axis, and the Immunoskeletal Interface in Physiological Bone Turnover and Osteoporosis

Although it has long been recognized that inflammation, a consequence of immune-driven processes, significantly impacts bone turnover, the degree of centralization of skeletal and immune functions has begun to be dissected only recently. It is now recognized that formation of osteoclasts, the bone resorbing cells of the body, is centered on the key osteoclastogenic cytokine, receptor activator of NF- κ B ligand (RANKL). Although numerous inflammatory cytokines are now recognized to promote osteoclast formation and skeletal degradation, with just a few exceptions, RANKL is now considered to be the final downstream effector cytokine that drives osteoclastogenesis and regulates osteoclastic bone resorption. The biological activity of RANKL is moderated by its physiological decoy receptor, osteoprotegerin (OPG). New discoveries concerning the sources and regulation of RANKL and OPG in physiological bone turnover as well as under pathological (osteoporotic) conditions continue to be made, opening a window to the complex regulatory processes that control skeletal integrity and the depth of integration of the skeleton within the immune response. This paper will examine the interconnection between bone turnover and the immune system and the implications thereof for physiological and pathological bone turnover.

HIV and its effects on bone: a primer for rheumatologists

PURPOSE OF REVIEW

As patients with HIV are living longer because of effective treatments, rates of comorbid chronic diseases such as bone complications are increasing. There is a growing body of literature showing increased rates of osteopenia and osteporosis in the HIV population. Less is known about the risk of fracture, as well as other bone complications, such as avascular necrosis (AVN).

RECENT FINDINGS

Increased rates of osteopenia and osteoporosis are seen in the HIV population, likely secondary to an interaction of traditional osteoporotic and HIV-specific risk factors, and possibly the effect of antiretroviral therapy (ART). There are conflicting recent data as to whether the decrease in bone mineral density seen in the HIV population, specifically with particular ART regimens, translates into an increased risk of fracture. Conflicting evidence emerges from recent studies exploring whether supplementation of vitamin D and calcium can prevent the bone loss seen with specific ART regimens.

SUMMARY

Bone disease is common in the HIV population, and will likely be a medical problem increasingly seen by rheumatologists. The role of ART regimens on bone complications such as fracture and AVN is unclear, and further research in this area as well as possible prevention strategies are needed.

Osteoporosis and bone health in HIV

Patients with HIV can develop several complications that involve bone including low bone mineral density and osteoporosis, osteonecrosis, and rarely osteomalacia. Low bone mineral density leading to osteoporosis is the most common bone pathology. This may result from HIV infection (directly or indirectly), antiretroviral toxicity, or as a consequence of other co-morbidities. The clinical relevance of osteoporosis in HIV infection has been uncertain; however, fragility fractures are increasingly reported in HIV-infected patients. Further research is required to understand the pathogenesis of osteoporosis in HIV-infected patients and determine effective management; however, initiation of antiretroviral therapy seems to accelerate (in the short-term) bone demineralization. Tenofovir may be associated with a greater degree of short-term loss of bone density than other antiviral agents and the potential long-term bone dysfunction is unclear. As the HIV-infected population ages, screening for low bone mineral density will become increasingly important.

Fractures after antiretroviral initiation

BACKGROUND

Bone mineral density declines by 2-6% within 1-2 years after initiation of antiretroviral therapy (ART); however, it is uncertain whether this results in an immediate or cumulative increase in fracture rates.

METHODS

We evaluated the incidence and predictors of fracture in 4640 HIV-positive participants from 26 randomized ART studies followed in the AIDS Clinical Trials Group (ACTG) Longitudinal-Linked Randomized Trial study for a median of 5 years. Fragility and nonfragility fractures were recorded prospectively at semiannual visits. Incidence was calculated as fractures/total person-years. Cox proportional hazards models evaluated effects of traditional fracture risks, HIV disease characteristics, and ART exposure on fracture incidence.

RESULTS

Median (interquartile range) age was 39 (33, 45) years; 83% were men, 48% white, and median nadir CD4 cell count was 187 (65, 308) cells/μl. Overall, 116 fractures were reported in 106 participants with median time-to-first fracture of 2.3 years. Fracture incidence was 0.40 of 100 person-years among all participants and 0.38 of 100 person-years among 3398 participants who were ART naive at enrollment into ACTG parent studies. Among ART-naive participants, fracture rates were higher within the first 2 years after ART initiation (0.53/100 person-years) than subsequent years (0.30/100 person-years). In a multivariate analysis of ART-naive participants, increased hazard of fracture was associated with current smoking and glucocorticoid use but not with exposure to specific antiretrovirals.

CONCLUSION

Fracture rates were higher within the first 2 years after ART initiation, relative to subsequent years. However, continuation of ART was not associated with increasing fracture rates in these relatively young HIV-positive individuals.

Hip bone geometry in HIV/HCV-co-infected men and healthy controls

People with both HIV and hepatitis C are more likely than those with HIV alone to have wrist, hip, and spine fractures. We compared hip strength between HIV/HCV-co-infected men and healthy men and found that HIV/HCV-co-infected men had decreased hip strength due to lower lean body mass.

INTRODUCTION

Hepatitis C co-infection is a risk factor for fragility fracture among HIV-infected populations. Whether bone strength is compromised in HIV/HCV-co-infected patients is unknown.

METHODS

We compared dual-energy x-ray absorptiometry (DXA)-derived hip geometry, a measure of bone strength, in 88 HIV/HCV-co-infected men from the Johns Hopkins HIV Clinic to 289 men of similar age and race and without HIV or HCV from the Boston Area Community Health Survey/Bone Survey. Hip geometry was assessed at the narrow neck, intertrochanter, and shaft using hip structural analysis. Lean body mass (LBM), total fat mass (FM), and fat mass ratio (FMR) were measured by whole-body DXA. Linear regression was used to identify body composition parameters that accounted for differences in bone strength between cohorts.

RESULTS

HIV/HCV-co-infected men had lower BMI, LBM, and FM and higher FMR compared to controls (all p < 0.05). At the narrow neck, significant differences were observed between HIV/HCV-co-infected men and controls in bone mineral density, cross-sectional area, section modulus, buckling ratio, and centroid position. After adjustment for race, age, smoking status, height, and weight, only buckling ratio and centroid position remained significantly different between cohorts (all p < 0.05). Substituting LBM, FM, and FMR for weight in the multivariate model revealed that differences in LBM, but not FM or FMR, accounted for differences in all narrow neck parameters between cohorts, except buckling ratio and centroid position.

CONCLUSION

HIV/HCV-co-infected men have compromised hip strength at the narrow neck compared to uninfected controls, which is attributable in large part to lower lean body mass.

Overall benefit of antiretroviral treatment on the risk of fracture in HIV: nested case-control analysis in a health-insured population

OBJECTIVES

Fractures are common and associated with multiple risk factors. We assessed the risks of fracture associated with time-dependent, differential antiretroviral drug exposures among a cohort of persons with HIV infection.

DESIGN

Nested case-control study from an HIV cohort of 59,594 medically insured persons with HIV infection enrolled in a medical care between January 1997 and March 2008.

METHODS

Cases were participants with a low-impact, nontraumatic fracture identified by ICD-9-CM codes; noncases were 1:4 matched and without fracture.

RESULTS

Cases included 2,477 persons with HIV infection with fractures, who were risk-set matched to 9,144 persons with HIV infection without fractures. Exposure to antiretroviral therapy by drug class and by duration (any drug/class) was associated with reduced risk for fracture. Drug-specific antiretroviral exposures over time identified an increased risk for fracture associated with darunavir, delavirdine and saquinavir, whereas reduced risk was associated with efavirenz, emtricitabine, lamivudine, tenofovir, and zidovudine. An initial null risk became a reduced risk with increased duration for nevirapine. In a similar pattern, abacavir, didanosine, nelfinavir, ritonavir and stavudine were initially associated with increased risk for fracture, after which the risk became null with increased duration of exposure. Null or uncertain risk for fracture was associated with amprenavir, atazanavir, enfuvirtide, fosamprenavir, indinavir, lopinavir, tipranavir, and zalcitabine.

CONCLUSION

Our findings suggest an overall reduced risk for facture in persons treated versus not treated with antiretroviral drugs for HIV infection. Differential drug-specific exposure-response relationships for fracture will need to be further evaluated in other study populations.

Priority issues concerning HIV infection among women

During the last decade, the enormous impact the global HIV epidemic was having on women's health was fully recognized. However, this recognition has not wholly extended to the domestic setting; in much of the United States, the dominant focus remains on HIV infection among men who have sex with men. The relatively low prevalence of HIV infection among U.S. women (a huge population group) versus men who have sex with men and injection drug users (much smaller groups) contributes to the perception that HIV is not a major domestic women's health consideration.

Fracture risk by HIV infection status in perinatally HIV-exposed children

The objective of this study was to examine the incidence of fractures in HIV-infected children and comparable HIV-exposed, uninfected (HEU) children in a multicenter, prospective cohort study (PACTG 219/219C) in the United States. The main outcome was first fracture during the risk period. Nine fractures occurred in 7 of 1326 HIV-infected and 2 of 649 HEU children, corresponding to incidence rates of 1.2 per 1000 person-years and 1.1 per 1000 person-years, respectively. The incidence rate ratio was 1.1 (95% CI 0.2, 5.5). There was no evidence of a substantially increased risk of fracture in HIV-infected compared to HEU children.

Higher rates of bone loss in postmenopausal HIV-infected women: a longitudinal study

CONTEXT AND OBJECTIVE

The objective of the study was to assess the effects of HIV infection and antiretroviral therapy on change in bone mineral density (BMD) in postmenopausal minority women.

DESIGN, SETTING, AND PATIENTS

We report a longitudinal analysis of change in BMD with a median duration of 15.4 (interquartile range 13.1, 20.7) months in a prospective cohort study of 128 (73 HIV+, 55 HIV-) postmenopausal Hispanic and African-American women.

MAIN OUTCOME MEASURES

Annualized change in BMD by dual-energy x-ray absorptiometry and correlation with baseline markers of bone turnover and serum levels of inflammatory cytokines were measured.

RESULTS

HIV+ women were younger (56 ± 1 vs. 59 ± 1 yr, P < 0.05) and had lower body mass index (BMI; 28 ± 1 vs. 31 ± 1 kg/m(2), P < 0.01). The majority of HIV+ women were on established antiretroviral therapy for more than 3 yr. At baseline, BMD, adjusted for age, race, and BMI, was lower in HIV+ women at the lumbar spine (LS), total hip, and radius and serum C-telopeptide was higher. Annualized rates of bone loss adjusted for baseline BMD were higher in HIV+ women by 2.4-fold at the LS (-1.2 ± 0.3% vs. -0.5 ± 0.3%, P = 0.0009), 3.7-fold at the one third radius (-1.1 ± 0.2% vs. -0.3 ± 0.2, P = 0.006) and 1.7-fold at the ultradistal radius (-1.2 ± 0.2% vs. -0.7 ± 0.2%, P = 0.02). In multivariate analysis, HIV+ status predicted bone loss at the LS, total hip, and ultradistal radius. Among HIV+ women, lower BMI, higher markers of bone turnover levels, and tenofovir were associated with more bone loss.

CONCLUSION

HIV+ postmenopausal minority women had lower BMD, increased bone turnover, and higher rates of bone loss than HIV- women. These features may place these women at increased risk for fracture as they age.

Effects of vitamin D deficiency and combination antiretroviral therapy on bone in HIV-positive patients

OBJECTIVES

In the era of combination antiretroviral therapy (cART), vitamin D deficiency, low bone mineral density (BMD) and fractures have emerged as subjects of concern in HIV-positive patients. Testing for vitamin D deficiency has been widely adopted in clinical practice even though the benefits of vitamin D supplementation in this population remain uncertain. The objective of this review was to evaluate the evidence for such a strategy.

DESIGN

Systematic review of the literature on vitamin D deficiency in HIV infection, the effects of cART on vitamin D status, and the effects of vitamin D deficiency and cART on parathyroid hormone (PTH), bone turnover, BMD and the incidence of fractures in HIV-positive patients.

METHODS

PubMed was used to identify relevant articles up to September 2011.

RESULTS

Vitamin D deficiency, secondary hyperparathyroidism and low BMD are common in HIV-positive patients. Efavirenz is associated with a reduction in 25-hydroxy vitamin D levels, tenofovir with secondary hyperparathyroidism, and cART with increased bone turnover and low BMD. The clinical significance of low BMD, however, remains unclear, especially in younger patients. Although the incidence of fractures may be increased in HIV-positive patients, the contribution of low BMD and vitamin D deficiency to these fractures is uncertain. Limited data on vitamin D supplementation in HIV-positive patients have shown transient, beneficial effects on PTH, but no effects on BMD.

CONCLUSION

The benefits of vitamin D supplementation in this population need to be demonstrated before widespread 'test and treat' policies can be recommended as part of routine clinical practice.

Incidence of low and high-energy fractures in persons with and without HIV infection: a Danish population-based cohort study

OBJECTIVE

To compare fracture risk in persons with and without HIV infection and to examine the influence of highly active antiretroviral therapy (HAART) initiation on risk of fracture.

DESIGN

Population-based nationwide cohort study using Danish registries.

METHODS

Outcome measures were time to first fracture at any site, time to first low-energy and high-energy fracture in HIV-infected patients (n = 5306) compared with a general population control cohort (n = 26 530) matched by sex and age during the study period 1995-2009. Cox regression analyses were used to estimate incidence rate ratios (IRRs).

RESULTS

HIV-infected patients had increased risk of fracture [IRR 1.5, 95% confidence interval (CI) 1.4-1.7] compared with population controls. The relative risk was lower in HIV-monoinfected patients (IRR 1.3, 95% CI 1.2-1.4) than in HIV/hepatitis C virus (HCV)-coinfected patients (IRR 2.9, 95% CI 2.5-3.4).Both HIV-monoinfected and HIV/HCV-coinfected patients had increased risk of low-energy fracture, IRR of 1.6 (95% CI 1.4-1.8) and 3.8 (95% CI 3.0-4.9). However, only HIV/HCV-coinfected patients had increased risk of high-energy fracture, IRR of 2.4 (95% CI 2.0-2.9). Among HIV-monoinfected patients the risk of low-energy fracture was only significantly increased after HAART exposure, IRR of 1.8 (95% CI 1.5-2.1). The increased risk in HAART-exposed patients was not associated with CD4 cell count, prior AIDS, tenofovir or efavirenz exposure, but with comorbidity and smoking.

CONCLUSION

HIV-infected patients had increased risk of fracture compared with population controls. Among HIV-monoinfected patients the increased risk was observed for low-energy but not for high-energy fractures, and the increased risk of low-energy fracture was only observed in HAART-exposed patients.

Prevention of bone loss and management of fracture risk in HIV-infected individuals: case studies and recommendations for different patient subgroups

Increased life-expectancy and the need for long-term antiretroviral therapy have brought new challenges to the clinical management of HIV-infected individuals. While the prevalence of osteoporosis and fractures is probably increased in HIV-infected patients, optimal strategies for risk assessment and treatment in this relatively young population are yet to be defined. Prevention of bone loss is likely to become an important component of HIV care as the HIV-infected patient population grows older. In this article, we present an overview of the literature on bone loss in individuals with HIV and discuss the practical application of the European AIDS Clinical Society (EACS) guidelines to a range of clinical case scenarios.

HIV and bone metabolism

The skeleton is an organ whose integrity is maintained by constant lifelong renewal involving coordinated removal of worn bone by osteoclasts and resynthesis of new bone by osteoblasts. In young adult humans and animals this process is homeostatic with no net gain or loss of bone mass. With natural aging and exacerbated by numerous pathological conditions, bone removal exceeds bone formation, disrupting homeostasis and resulting in bone loss. Over time, skeletal decline reaches clinical significance with development of osteopenia and eventually osteoporosis, conditions that dramatically increase bone fragility and the risk of fracture. Bone fractures can be devastating with significant morbidity and mortality. Over the last decade, it has become clear that skeletal renewal is strongly influenced by the immune system, a consequence of deep integration and centralization of common cell types and cytokine mediators, which we have termed the "immuno-skeletal interface." Consequently, dysregulated skeletal renewal and bone loss is a common feature of inflammatory conditions associated with immune activation. Interestingly, bone loss is also associated with conditions of immunodeficiency, including infection by the human immunodeficiency virus (HIV) that leads to acquired immunodeficiency syndrome (AIDS). Disruptions to the immuno-skeletal interface drive skeletal deterioration contributing to a high rate of bone fracture in HIV infection. This review examines current knowledge concerning the prevalence and etiology of skeletal complications in HIV infection, the effect of antiretroviral therapies (ART) on the skeleton, and how disruption of the immuno-skeletal interface may underlie bone loss in HIV infection and ART.

Role of zoledronic acid in the prevention and treatment of osteoporosis

Taken once a year, intravenous zoledronic acid (Zol) (Reclast® or Aclasta®) is a third-generation nitrogen-containing bisphosphonate that is effective compared with placebo in reducing the risk of fractures in patients with postmenopausal osteoporosis and recent low-trauma hip fracture. In glucocorticoid-induced osteoporosis, there is no significant difference between Zol and risedronate for new fractures. Improvements in bone mineral density and early reduction of bone remodeling markers are observed in postmenopausal osteoporosis, recent low-trauma hip fracture, and glucocorticoid-induced osteoporosis. Given that Zol is generally well tolerated and very convenient, it is an interesting therapeutic option for aging patients who take multiple oral drugs, who have adherence or gastrointestinal tolerance issues, and who have an indication for oral bisphosphonates. Zol is not recommended for patients with severe renal impairment. Vitamin D deficiency should be corrected before the administration of Zol.

High frequency of poor locomotor performance in HIV-infected patients

OBJECTIVES

To provide up-to-date assessments of locomotor function in HIV-infected patients and to identify potential determinants of impaired function.

DESIGN

Cross-sectional study in 324 HIV-1-infected adults from the French Agency for AIDS and Hepatitis Research (ANRS) CO3 Aquitaine Cohort using standardized locomotor tests.

METHODS

Patients underwent standardized testing assessing balance, walking ability, functional capacity and lower limb muscle performance. Poor test performance was defined by cut-offs based on age-specific data of the general population. Factors associated with poor test performance were studied by logistic regression.

RESULTS

Median age was 48 years, 80% were men and 89% were on antiretroviral treatment. The most frequently altered locomotor test was the five-times sit-to-stand (5STS) test, assessing lower limb muscle performance (poor performance: 53%). In multivariable analysis, time since HIV diagnosis was associated with poor 5STS performance [odds ratio (OR) = 1.08 per year; 95% confidence interval (CI): 1.03, 1.13]. In patients below 30 years, elevated BMI was associated with higher likelihood of good performance (OR = 0.81 per kg/m(2); 95% CI: 0.69, 0.93), whereas in those above 70 years this association was reversed (OR = 1.30 per kg/m(2); 95% CI: 1.10, 1.53; P < 10(-3) for interaction). We found no association with antiretroviral treatment.

CONCLUSION

One of two adults with controlled HIV infection had poor lower limb muscle performance, which might put this population at risk of falls and fracture. The 5STS test is a simple test that should be recommended to assess muscular performance in HIV care.