Continuous antiretroviral therapy decreases bone mineral density

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.

Prospective one-year bone loss in treatment-naïve HIV+ men and women on single or multiple drug HIV therapies

Antiretroviral therapy has decreased the rate of HIV-related mortality and extended the life span of HIV patients. Current guidelines recommend the use of a 3-drug regimen, such as two nucleoside reverse transcriptase inhibitors and a protease inhibitor, boosted by ritonavir. Osteoporosis can be associated with the HIV disease itself or with antiretroviral therapy. Many trials have been conducted employing a single drug regimen to simplify antiretroviral therapy but few studies assessed the effect of the single drug regimen on bone mineral density (BMD). The objectives of the study were to assess and compare the relative (%) changes in lumbar spine and hip BMD over 48 weeks in HIV patients treated with mono or triple antiretroviral regimens The study was conducted using data from a randomized trial (MONARK) conducted in 136 antiretroviral-naïve HIV patients (89 men and 47 women) comparing the antiviral efficacy of a single-drug protease inhibitor regimen of lopinavir/ritonavir (LPV/r) versus LPV/r in combination with zidovudine (ZDV) and lamivudine (3TC). Lumbar spine and total hip BMD were assessed in 100 patients by dual-energy X-ray absorptiometry at baseline and 48 weeks. 48 week-BMD data were available for 43 patients (mean age 37years) with a mean baseline lumbar spine Z-score of -0.1 in the LPV/r monotherapy group and for 25 patients (mean age 35.8years) with a mean baseline lumbar spine Z-score of -0.2 in the LPV/r+ZDV+3TC group. After 48weeks, lumbar spine BMD significantly decreased by 4.4% (-5.1% to -2.1%, P≤0.001) in the LPV/r group and by 4.0% (-5.0% to -1.7%, P≤0.0001) in the LPV/r+ZDV+3TC group. There was no significant difference in BMD changes between the two groups. These results suggest that bone loss is observed 48 weeks after the initiation of antiretroviral therapy, whether the patients receive a single- or triple-drug antiretroviral regimen.

Markers of bone turnover are elevated in patients with antiretroviral treatment independent of the substance used

OBJECTIVES

Osteoporosis and bone fractures are correlated to antiretroviral treatment. It is not clear whether some substances comprise greater risks of bone loss than others.

METHODS

We measured pyridinoline, deoxypyridinoline crosslinks, and bone-specific alkaline phosphatase in 113 HIV-positive patients. We compared patients with and without antiretroviral treatment. We then compared patients with versus without tenofovir and patients with protease inhibitor versus nonnucleoside reverse transcriptase inhibitor use.

RESULTS

Bone-specific alkaline phosphatase, pyridinoline, and deoxypyridinoline crosslinks were significantly higher in patients with antiretroviral treatment compared with patients without antiretroviral treatment: 24.5 versus 13.04 pg/L (P < 0.001), 82.73 versus 51.93 nmol/mmol (P < 0.001), and 16.56 versus 9.94 nmol/mmol (P < 0.001), respectively. In contrast, no difference was found between patients with and without tenofovir: 25.38 versus 20.02 pg/l (P = 0.1); 79.85 versus 83.95 nmol/mmol (P = 0.64), and 19.12 versus 14.00 nmol/mmol (P = 0.14), respectively. Comparison between patients with protease inhibitor versus nonnucleoside reverse transcriptase inhibitor yielded no difference either: 23.07 versus 27.18 pg/L (P = 0.24), 92.96 versus 80.73 nmol/mmol (P = 0.36), and 18.22 versus 16.39 nmol/mmol (P = 0.55).

CONCLUSION

Markers for bone turnover are higher in treated compared with untreated patients. No difference concerning tenofovir use or protease inhibitor versus nonnucleoside reverse transcriptase inhibitor use could be found.

Secondary complications and co-infections in the HIV-infected adolescent in the antiretroviral era

PURPOSE OF REVIEW

The number of HIV-infected adolescents is increasing dramatically. With combination antiretroviral therapy, they are expected to live well into adulthood. However, complications are emerging at a higher rate in the HIV-infected population compared to the general population. HIV-infected adolescents are also at a high risk of sexually transmitted co-infections. This article reviews the main secondary complications and co-infections in the HIV-infected adolescent.

RECENT FINDINGS

HIV-infected adolescents are at a high risk of sexually transmitted infections. A careful, age-appropriate and developmentally appropriate inquiry into the individual's sexual behavior to assess risk is paramount, in addition to regular screening at medical visits. Treating co-infections is not only important for HIV-infected individuals, but also limits HIV transmission to others. In addition, monitoring and addressing modifiable secondary risk factors for complications such as renal disease, osteopenia or osteoporosis, and cardiovascular disease are critical, well before the onset of clinically apparent disease. Using antiretroviral therapy to suppress viral replication and inflammation appears to be a promising strategy for decreasing secondary complication risk, and likely overshadows the toxicities associated with the long-term use of certain antiretrovirals.

SUMMARY

Assessing and addressing the risk of secondary complications and co-infections in the HIV-infected adolescent is crucial for optimal length and quality of life.

HIV status is an independent risk factor for reporting lower urinary tract symptoms

PURPOSE

HIV/AIDS is a worldwide epidemic. Limited evidence suggests that men infected with HIV/AIDS are at increased risk for lower urinary tract symptoms. We determined whether HIV/AIDS status is an independent risk factor for self-reported bothersome lower urinary tract symptoms in a large contemporary cohort.

MATERIALS AND METHODS

We performed a cross-sectional, Internet based survey of urinary quality of life outcomes in adult HIV infected and HIV uninfected men who have sex with men. The main outcome measure was International Prostate Symptom Score.

RESULTS

Of respondents with complete data 1,507 were HIV uninfected (median age 42 years, mean 43) and 323 HIV infected (median age 45 years, mean 45.1). Of the HIV infected respondents 148 were nonAIDS defining HIV infected and 175 were AIDS defining HIV infected. After adjusting for age and other comorbid conditions, nonAIDS defining HIV infected and AIDS defining HIV infected status increased the odds of severe lower urinary tract symptoms by 2.07 (95% CI 1.04-3.79) and 2.49 (95% CI 1.43-4.33), respectively. HIV infected men had a worse total International Prostate Symptom Score for all domains including quality of life compared to HIV uninfected men. Within the population of men with HIV, those with AIDS had worse mean total International Prostate Symptom Score and all individual International Prostate Symptom Score components relative to nonAIDS defining HIV infected men.

CONCLUSIONS

HIV status is an independent risk factor for bothersome lower urinary tract symptoms. The odds of severe lower urinary tract symptoms are greater in HIV infected men with a history of AIDS.

Increased risk of fragility fractures among HIV infected compared to uninfected male veterans

Background

HIV infection has been associated with an increased risk of fragility fracture. We explored whether or not this increased risk persisted in HIV infected and uninfected men when controlling for traditional fragility fracture risk factors.

Methodology/Principal Findings

Cox regression models were used to assess the association of HIV infection with the risk for incident hip, vertebral, or upper arm fracture in male Veterans enrolled in the Veterans Aging Cohort Study Virtual Cohort (VACS-VC). We calculated adjusted hazard ratios comparing HIV status and controlling for demographics and other established risk factors. The sample consisted of 119,318 men, 33% of whom were HIV infected (34% aged 50 years or older at baseline, and 55% black or Hispanic). Median body mass index (BMI) was lower in HIV infected compared with uninfected men (25 vs. 28 kg/m²; p<0.0001). Unadjusted risk for fracture was higher among HIV infected compared with uninfected men [HR: 1.32 (95% CI: 1.20, 1.47)]. After adjusting for demographics, comorbid disease, smoking and alcohol abuse, HIV infection remained associated with an increased fracture risk [HR: 1.24 (95% CI: 1.11, 1.39)]. However, adjusting for BMI attenuated this association [HR: 1.10 (95% CI: 0.97, 1.25)]. The only HIV-specific factor associated with fragility fracture was current protease inhibitor use [HR: 1.41 (95% CI: 1.16, 1.70)].

Conclusions/Significance

HIV infection is associated with fragility fracture risk. This risk is attenuated by BMI.

Bone disease in HIV infection

The advent of highly active anti-retroviral therapy (HAART) has dramatically decreased the rate of AIDS-related mortality and significantly extended the life span of patients with AIDS.A variety of metabolic side effects are associated with these therapies, one of which is metabolic bone disease. The causes of low bone mineral density (BMD) in individuals with HIV infection appear to be multifactorial and likely represent a complex interaction between HIV infection, traditional osteoporosis risk factors, and antiretroviral related factors.This review summarizes the clinical evidence linking HIVassociated osteoporosis to direct infection and antiretroviral therapy use. The purported mechanisms involved in bone loss are also reviewed. Additionally, recommendations regarding the pharmacologic management of HIV/HAART-related osteoporosis are given. In conclusion, we make the point that HIV infection should be considered as a risk factor for bone disease.

HIV-1 infection and antiretroviral therapies: risk factors for osteoporosis and bone fracture

PURPOSE OF REVIEW

Patients with HIV-1 infection/AIDS are living longer due to the success of highly active antiretroviral therapy (HAART). However, serious metabolic complications including bone loss and fractures are becoming common. Understanding the root causes of bone loss and its potential implications for aging AIDS patients will be critical to the design of effective interventions to stem a tidal wave of fractures in a population chronically exposed to HAART.

RECENT FINDINGS

Paradoxically, bone loss may occur not only due to HIV/AIDS but also as a consequence of HAART. The cause and mechanisms driving these distinct forms of bone loss, however, are complex and controversial. This review examines our current understanding of the underlying causes of HIV-1 and HAART-associated bone loss, and recent findings pertaining to the relevance of the immuno-skeletal interface in this process.

SUMMARY

It is projected that by 2015 more than half of the HIV/AIDS population in the USA will be over the age of 50 and the synergy between HIV and/or HAART-related bone loss with age-associated bone loss could lead to a significant health threat. Aggressive antiresorptive therapy may be warranted in high-risk patients.

High prevalence of and progression to low bone mineral density in HIV-infected patients: a longitudinal cohort study

BACKGROUND

Low bone mineral density (BMD) is an emerging metabolic condition in HIV-infected patients; however, data on progression of this disease are scarce.

METHODS

We studied 671 patients with at least one dual-energy X-ray absorptiometry scan (391 of them ≥2 scans) to determine the prevalence and progression of BMD and establish related factors. Linear regression and logistic polytomic regression were used for the cross-sectional study and mixed effects and generalized estimating equations were used for the longitudinal study.

RESULTS

Osteopenia and osteoporosis were diagnosed in 47.5 and 23%, respectively. Progression to bone demineralization was observed in 28% of the patients over a median of 2.5 years (12.5% progressed to osteopenia and 15.6% to osteoporosis). In the 105 patients with at least 5 years of follow-up, progression was 47% (18% to osteopenia; 29% to osteoporosis). Factors associated with bone loss and progression were age [odds ratio (OR) 1.07; 95% confidence interval (CI) 1.05-1.08; P < 0.0001], male sex (OR 2.23; 95% CI 1.77-2.8; P < 0.0001), low body mass index (OR 1.14; 95% CI 1.11-1.17; P < 0.0001), time on protease inhibitor (OR 1.18; 95% CI 1.12-1.24; P < 0.0001), time on tenofovir (OR 1.08; 95% CI 1.03-1.14; P < 0.0019), and current use of protease inhibitors (OR 1.64; 95% CI 1.35-2.04; P < 0.0001).

CONCLUSIONS

Our results show a high prevalence of and considerable progression to osteopenia/osteoporosis in our cohort. Our findings support the importance of applying adequate strategies to prevent bone demineralization and of close monitoring of BMD in HIV-infected patients, specifically in at-risk patients who are taking antiretrovirals that affect bone mineralization.

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

BACKGROUND

The clinical importance of the association of HIV infection and antiretroviral therapy (ART) with low bone mineral density (BMD) in premenopausal women is uncertain because BMD stabilizes on established ART and fracture data are limited.

METHODS

We measured time to first new fracture at any site with median follow-up of 5.4 years in 2391 (1728 HIV-infected, 663 HIV-uninfected) participants in the Women's Interagency HIV Study (WIHS). Self-report of fracture was recorded at semiannual visits. Proportional hazard models assessed predictors of incident fracture.

RESULTS

At baseline, HIV-infected women were older (40 ± 9 vs. 36 ± 10 years, P < 0.0001), more likely to report postmenopausal status and be hepatitis C virus-infected, and weighed less than HIV-uninfected women. Among HIV-infected women, mean CD4(+) cell count was 482 cells/μl; 66% were taking ART. Unadjusted incidence of fracture did not differ between HIV-infected and uninfected women (1.8 vs. 1.4/100 person-years, respectively, P = 0.18). In multivariate models, white (vs. African-American) race, hepatitis C virus infection, and higher serum creatinine, but not HIV serostatus, were statistically significant predictors of incident fracture. Among HIV-infected women, older age, white race, current cigarette use, and history of AIDS-defining illness were associated with incidence of new fracture.

CONCLUSION

Among predominantly premenopausal women, there was little difference in fracture incidence rates by HIV status, rather traditional risk factors were important predictors. Further research is necessary to characterize fracture risk in HIV-infected women during and after the menopausal transition.

Prevalence of bone mineral density abnormalities and related risk factors in an ambulatory HIV clinic population

Bone mineral density (BMD) abnormalities are observed frequently among human immunodeficiency virus (HIV)-infected patients. Risk factors for reduced BMD in the setting of HIV have been previously studied, but detailed antiretroviral treatment history is often not available. A cross-sectional observational study was conducted between 2005 and 2007 among unselected HIV-infected adults attending an ambulatory urban HIV clinic. Dual-energy X-ray absorptiometry (DXA) scans of lumbar spine and femoral neck, full laboratory profile, detailed questionnaire, and antiretroviral history were obtained. Univariate and multivariate logistic regression analyses were performed to investigate factors associated with BMD below the expected range for age. Two hundred ninety patients completed the study: 80% Caucasians, 89% males, with median age of 49 yr. Low BMD as assessed by Z-score was present in 19.7% of the patients. By multivariate analysis, only lower body mass index (BMI) was an independent risk factor for low BMD. Cumulative exposure to protease inhibitors, non-nucleosides, and individual nucleoside and nucleotide analogs were not independently associated with low BMD. In conclusion, a 19.7% prevalence of abnormal BMD by DXA scan was identified in an unselected group of HIV-infected adults. Lower BMI was independently associated with low BMD. No correlation was found between abnormal BMD and cumulative exposure to any antiretroviral agents.

Prospective study of bone mineral density changes in aging men with or at risk for HIV infection

OBJECTIVE

To investigate rates and predictors of change in bone mineral density (BMD) in a cohort of aging men with or at risk for HIV infection.

DESIGN

A prospective cohort study among 230 HIV-infected and 159 HIV-uninfected men aged at least 49 years.

METHODS

Longitudinal analyses of annual change in BMD at the femoral neck, total hip, and lumbar spine.

RESULTS

At baseline, 46% of men had normal BMD, 42% had osteopenia, and 12% had osteoporosis. Of those men with normal BMD, 14% progressed to osteopenia and 86% continued to have normal BMD. Of the men initially with osteopenia, 12% progressed to osteoporosis and 83% continued to have osteopenia. Osteopenia incidence per 100 person-years at risk was 2.6 for HIV-uninfected men and 7.2 for HIV-infected men; osteoporosis incidence was 2.2 per 100 person-years at risk among men with osteopenia, regardless of HIV status. In multivariable analysis of annual change in BMD at the femoral neck, we found a significant interaction between heroin use and AIDS diagnosis, such that the greatest bone loss occurred with both AIDS and heroin use (adjusted predicted mean annual bone loss 0.0196 g/cm). Hepatitis C virus seropositivity was also associated with femoral neck bone loss (P = 0.04). The interaction between AIDS and heroin use also was associated with bone loss at the total hip, as was current methadone use (P < 0.01).

CONCLUSION

We found an association of heroin use and AIDS with BMD change, suggesting that heroin users with AIDS may be at particular risk for bone loss.

High prevalence of reduced bone mineral density in primary HIV-1-infected men

OBJECTIVE

To assess the bone mineral density (BMD) in a cohort of men with primary HIV-1 infection (PHI).

METHODS

Thirty-three men with PHI had a dual-energy X-ray absorptiometry (DXA) of the lumbar spine, femoral neck and total hip. Osteopenia and osteoporosis were defined according to WHO criteria as T-scores between -1 and -2.5 and -2.5 or less, respectively. The association between clinical and laboratory parameters and BMD was investigated using multivariable linear regression analysis.

RESULTS

Mean age was 38 (SD 9) years and mean body mass index (BMI) 22.7 (SD 3.3) kg/m. Twenty-four men (73%) had a negative or indeterminate Western blot, 32 men (97%) were combination antiretroviral therapy-naive. Mean plasma HIV-1 RNA was 5.0 (SD 1.2) log10 copies/ml. Mean lumbar spine T (-0.8, SD 1.3, P = 0.001) and Z-scores (-0.7, SD 1.3, P = 0.004) and femoral neck T-score (-0.5, SD 0.9, P = 0.003) were significantly lower compared to the reference population. 15/33 men (45%) had osteopenia and 2/33 (6%) osteoporosis. Markers of bone turnover did not differ between patients with or without osteopenia/osteoporosis. Age was negatively associated with femoral neck (beta-coefficient = -0.05, P < 0.001) and total hip T-scores (beta = -0.03, P = 0.04). BMI was associated with lumbar spine (beta = 0.3), femoral neck (beta = 0.2) and total hip (beta = 0.2) T-scores (P < 0.001) and thyroid-stimulating hormone (TSH) with lumbar spine (beta = 0.5, P = 0.045) and femoral neck T-scores (beta = 0.4, P = 0.005). Increased plasma viral load was associated with lower total hip T-scores (beta = -0.2, P = 0.02).

CONCLUSIONS

Reduced BMD was prevalent in PHI men and was associated with increased age, lower BMI and TSH levels, and higher levels of HIV-1 viremia.

The ageing of HIV: implications for geriatric medicine

The prevalence of human immunodeficiency virus (HIV) in the over 50 age group is increasing as a consequence of younger adults ageing with HIV, in addition to new diagnoses in later life. We conducted searches in MEDLINE for English language studies published between January 1984 and January 2010 using search terms 'HIV', 'AIDS', 'HIV testing' and 'HIV complications' and selected articles relevant to adults aged 50 years and over. The prevalence, natural history and complications of HIV infection and treatment in older adults are reviewed. In 2007 the Centers for Disease Control and Prevention in the United States reported that 16.8% of new diagnoses of HIV that year were in individuals aged over 50 years. Older adults are vulnerable to late or missed diagnosis, and poorer treatment outcomes, due to the misconception that they are not at risk. A heightened awareness of HIV as a possible diagnosis in older adults is becoming increasingly important. As the HIV population ages, the emergence of disease and treatment complications such as cardiovascular disease, osteoporosis and dementia are evident. Management of older adults with HIV and multiple co-morbidities presents challenges to infectious diseases physicians and geriatricians alike. Inclusion of older adults in future HIV clinical trials will help design healthcare models to provide for this growing population.

Bone mineral density changes in protease inhibitor-sparing vs. nucleoside reverse transcriptase inhibitor-sparing highly active antiretroviral therapy: data from a randomized trial

OBJECTIVE

The aim of the study was to compare changes in bone mineral density (BMD) over 144 weeks in HIV-infected patients initiating nucleoside reverse transcriptase inhibitor (NRTI)-sparing or protease inhibitor-sparing highly active antiretroviral therapy (HAART).

METHODS

Sixty-three HAART-naïve patients were randomized to zidovudine/lamivudine+efavirenz or lopinavir/ritonavir+efavirenz. We performed dual energy X-ray absorptiometry (DEXA) at baseline and at weeks 24, 48, 96 and 144 to evaluate lumbar spine and femoral neck (hip) BMD.

RESULTS

At baseline, 33 patients (55.9%) had low BMD (T-score < -1.0) and of these eight had osteoporosis (T-score < -2.5). Spine BMD declined in both arms until week 24, before stabilizing. In the NRTI-sparing arm, the mean percentage change from baseline was -2.7% [95% confidence interval (CI) -3.9 to -1.4] at week 24 and -2.5% (95% CI -5.4 to 0.3) at week 144, compared with -3.2% (95% CI -4.4 to -2.1) and -1.9% (95% CI -3.5 to -0.3) in the protease inhibitor-sparing arm. Hip BMD declined until week 48 before stabilizing. In the NRTI-sparing arm, BMD had decreased by -5.1% (95% CI -7.1 to -3.1) at week 48 and -4.5% (95% CI -6.9 to -2.1) at week 144, compared with -6.1% (95% CI -8.2 to -4.0) and -5.0% (95% CI -6.8 to -3.1) in the protease inhibitor-sparing arm. There were no significant differences between arms. Low baseline CD4 cell count was independently associated with spine (P=0.007) and hip (P=0.04) BMD loss and low body mass index with hip BMD loss (P=0.03).

CONCLUSION

Spine and hip BMD declined rapidly 24 to 48 weeks after initiating HAART, independent of the assigned drug class, but thereafter BMD values remained stable.

Bone changes and fracture risk in individuals infected with HIV

The life expectancy of individuals infected with HIV has improved greatly since the institution of combination antiretroviral therapy. However, many metabolic derangements have been discovered with long-term combination antiretroviral treatment, including lipodystrophy; insulin resistance; and, more recently, abnormal bone metabolism. It is well-documented that bone mineral density (BMD) in HIV-positive patients is lower compared with the expected BMD in non-HIV-positive patients. The underlying cause of lower BMD is unknown but is thought to be a multifactorial process. Conflicting evidence exists regarding the effect of antiretroviral exposure and duration of treatment, antiretroviral type, and cumulative HIV viral exposure on bone health. Here we review the bone changes that occur with HIV infection and treatment.

Antiretroviral therapy and management of HIV infection

Antiretroviral therapy of HIV infection has changed a uniformly fatal into a potentially chronic disease. There are now 17 drugs in common use for HIV treatment. Patients who can access and adhere to combination therapy should be able to achieve durable, potentially lifelong suppression of HIV replication. Despite the unquestioned success of antiretroviral therapy, limitations persist. Treatment success needs strict lifelong drug adherence. Although the widely used drugs are generally well tolerated, most have some short-term toxic effects and all have the potential for both known and unknown long-term toxic effects. Drug and administration costs limit treatment in resource-poor regions, and are a growing concern even in resource rich settings. Finally, complete or near complete control of viral replication does not fully restore health. Long-term treated patients who are on an otherwise effective regimen often show persistent immune dysfunction and have higher than expected risk for various non-AIDS-related complications, including heart, bone, liver, kidney, and neurocognitive diseases.

High prevalence of severe vitamin D deficiency in combined antiretroviral therapy-naive and successfully treated Swiss HIV patients

OBJECTIVES

To evaluate the prevalence of 25-hydroxyvitamin D [25(OH)D] deficiency in HIV-positive patients, a population at risk for osteoporosis.

DESIGN

Retrospective assessment of vitamin D levels by season and initiation of combined antiretroviral therapy (cART).

METHODS

25(OH)D was measured in 211 HIV-positive patients: samples were taken before initiation of cART from February to April or from August to October as well as 12 (same season) and 18 months (alternate season) after starting cART. 1,25-Dihydroxyvitamin D [1,25(OH)2D] was measured in a subset of 74 patients. Multivariable analyses included season, sex, age, ethnicity, BMI, intravenous drug use (IDU), renal function, time since HIV diagnosis, previous AIDS, CD4 cell count and cART, in particular nonnucleoside reverse transcriptase inhibitor (NNRTI) and tenofovir (TDF) use.

RESULTS

At baseline, median 25(OH)D levels were 37 (interquartile range 20-49) nmol/l in spring and 57 (39-74) nmol/l in the fall; 25(OH)D deficiency less than 30 nmol/l was more prevalent in spring (42%) than in fall (14%), but remained unchanged regardless of cART exposure. In multivariable analysis, 25(OH)D levels were higher in white patients and those with a longer time since HIV diagnosis and lower in springtime measurements and in those with active IDU and NNRTI use. 1-Hydroxylation rates were significantly higher in patients with low 25(OH)D. Hepatitis C seropositivity, previous AIDS and higher CD4 cell counts correlated with lower 1,25(OH)2D levels, whereas BMI and TDF use were associated with higher levels. In TDF-treated patients, higher 1,25(OH)2D correlated with increases in serum alkaline phosphatase.

CONCLUSION

Based on the high rate of vitamin D deficiency in HIV-positive patients, systematic screening with consideration of seasonality is warranted. The impact of NNRTIs on 25(OH)D and TDF on 1,25(OH)2D needs further attention.

Unmet therapeutic needs in the new era of combination antiretroviral therapy for HIV-1

Significant advances in outcomes have been achieved with combination antiretroviral therapy (cART) in patients living with HIV. However, several ongoing needs remain with respect to the development of new treatments. The need for new or enhanced cART may become increasingly apparent as patients live longer with HIV and a greater proportion die from non-AIDS-related illnesses. Immunological response to cART is variable and immune failure occurs, despite virological control. Moreover, viral suppression can be incomplete due to insufficient antiviral efficacy, acquired or transmitted drug resistance, suboptimal pharmacokinetics/pharmacodynamics and lack of adherence. Chronic immune activation may continue even when viral replication is relatively restrained. Patients continue to experience cardiovascular and metabolic complications, due to disease, treatment and ageing. In addition, neurocognitive impairment and malignancy are important sources of ongoing morbidity despite cART. HIV also affects immune system senescence and bone turnover. This review discusses potential unmet needs with respect to these issues.

HIV and bone mineral density

PURPOSE OF REVIEW

This review details the clinical aspects and pathogenesis of low bone mineral density (BMD) in HIV, discusses broad management issues and outlines areas in which our understanding of this condition is incomplete.

RECENT FINDINGS

Low BMD is prevalent in HIV-infected patients, with traditional risk factors, HIV infection and exposure to antiretroviral therapy all contributing. The role of specific antiretrovirals in the development of low BMD remains controversial, but most changes arise at either antiretroviral therapy initiation or switch.

SUMMARY

Further research is needed to clarify mechanisms underlying low BMD in HIV, whether low BMD will translate to increased fractures and to determine the correct therapeutic approach to low BMD in HIV, particularly in younger HIV-infected patients.

Bone health in HIV infection

INTRODUCTION

Osteoporosis is among the chronic problems emerging as the human immunodeficiency virus (HIV)-positive population ages.

SOURCES OF DATA

We reviewed the English language bibliography using Pubmed 2.0, Web of Science and Embase for relevant abstracts and articles.

AREAS OF AGREEMENT

The prevalence of low bone mineral density (BMD) and fracture is increased in the HIV-positive population.

AREAS OF CONTROVERSY

The pathogenesis is multifactorial; there is some evidence that HIV infection is an independent risk factor and that highly active antiretroviral therapy has adverse skeletal effects.

GROWING POINTS

Physicians should routinely review the bone health of all HIV patients.

AREAS TIMELY FOR DEVELOPING RESEARCH

More studies of the mechanisms of bone loss, the skeletal effects of antiretroviral therapy and the therapeutic outcome of bone-protective therapy in HIV-positive individuals are needed.