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

Thirty-day hospital readmission rate among adults living with HIV

OBJECTIVE

Thirty-day hospital readmission rate is receiving increasing attention as a quality-of-care indicator. The objective of this study was to determine readmission rates and to identify factors associated with readmission among persons living with HIV.

DESIGN

Prospective multicenter observational cohort.

SETTING

Nine US HIV clinics affiliated through the HIV Research Network.

PARTICIPANTS

Patients engaged in HIV care during 2005-2010.

MAIN OUTCOME MEASURE(S)

Readmission rate was defined as the proportion of hospitalizations followed by a readmission within 30 days. Factors in multivariate analyses included diagnostic categories, patient demographic and clinical characteristics, and having an outpatient follow-up visit.

RESULTS

Among 11,651 total index hospitalizations, the 30-day readmission rate was 19.3%. AIDS-defining illnesses (ADIs, 9.6% of index hospitalizations) and non-AIDS-defining infections (26.4% of index hospitalizations) had readmission rates of 26.2 and 16.6%, respectively. Factors independently associated with readmission included lower CD4 cell count [adjusted odds ratio 1.80 (1.53-2.11) for CD4 cell count <50 vs. ≥351 cells/μl], longer length of stay [1.77 (1.53-2.04) for ≥9 days vs. 1-3 days], and several diagnostic categories including ADI. Having an outpatient follow-up clinic visit was not associated with lower readmission risk [adjusted hazard ratio 0.98 (0.88-1.08)].

CONCLUSION

The 19.3% readmission rate exceeds the 13.3% rate reported for the general population of 18-64-year-olds. HIV providers may use the 19.3% rate as a basis of comparison. Policymakers may consider the impact of HIV when estimating expected readmissions for a hospital or region. Preventing or recovering from severe immune dysfunction may be the most important factor to reducing readmissions.

Missed office visits and risk of mortality among HIV-infected subjects in a large healthcare system in the United States

Linkage and retention in care soon after HIV diagnosis improves clinical outcomes. Conversely, missed visits after diagnosis are associated with increased mortality in the public care setting. We analyzed mortality among newly diagnosed HIV patients ≥18 years old in a large private care setting between 01/01/1997 and 12/31/2009, comparing patients who missed visits in their first year following diagnosis (index period) with those who did not. Patients who died during the index period were excluded. Hazard ratios (HR) for association of missed visits and mortality were obtained by Cox proportional hazards regression, adjusting for patient demographics, CD4+ counts, and AIDS-defining conditions (CDC, 1993) at diagnosis. We also evaluated risk factors of missed visits by multivariable logistic regression. 2811 patients were included, of whom 65% had ≥1 missed visit, and 226 patients died during follow-up. Patients with ≥1 missed visit had a 71% increased mortality risk (HR=1.71, p=0.001) with 12% increased rate per missed visit (HR=1.12, p<0.001). Factors associated with missed visits were younger age (OR=1.69 compared to 60+ years), Black and Latino race/ethnicity (OR=1.54, 1.48 respectively, compared to Caucasians), injection drug use (OR=2.50 compared to men who have sex with men), and lower CD4+ (OR=1.43 for CD4+ 100-199 cells/μL, OR=1.39 for 50-99 cells/μL, and OR=1.63 for CD4+ <50 cells/μL, compared with CD4+ >500 cells/μL). In an insured patient population, missed visits in the first year of HIV care are common and associated with increased mortality. Early retention in HIV care is critical to improving outcomes.

Incident fractures in HIV-infected individuals: a systematic review and meta-analysis

OBJECTIVE(S)

Some but not all studies indicate that individuals with HIV infection are at an increased risk of fracture. We systematically reviewed the literature to investigate whether incidence of fracture (both overall and fragility) differs between individuals with and without HIV.

DESIGN

A systematic review and meta-analysis.

METHODS

Medline, Scopus and the Cochrane Library databases for all studies ever published up to 28 September 2012 and electronically available conference abstracts from CROI, ASBMR, IAS and AIDS were searched. All studies reporting incidence of all fracture and fragility fracture in HIV-infected adults were included. A random effects model was used to calculate pooled estimates of incidence rate ratios (IRRs) for studies that presented data for HIV-infected and controls. For all studies, incidence rates of fracture and predictors of fracture among HIV-infected individuals were summarized.

RESULTS

Thirteen eligible studies were analysed, of which seven included controls. Nine studies reported all incident fractures and 10 presented incident fragility fractures. The pooled IRR was 1.58 [95% confidence interval (CI) 1.25-2.00] for all fracture and 1.35 (95% CI 1.10-1.65) for fragility fracture. Smoking, white race and older age were consistent predictors for fragility fractures.

CONCLUSION

Our results indicate that HIV infection is associated with a modest increase in incident fracture. Future research should focus on clarifying risk factors, designing appropriate interventions and the long-term implications of this increased risk for an ageing HIV-infected population.

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.

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.

Time of progression to osteopenia/osteoporosis in chronically HIV-infected patients: screening DXA scan

BACKGROUND

Algorithms for bone mineral density (BMD) management in HIV-infected patients are lacking. Our objective was to assess how often a dual-energy x-ray absorptiometry (DXA) scan should be performed by assessing time of progression to osteopenia/osteoporosis.

METHODS

All DXA scans performed between 2000 and 2009 from HIV-infected patients with at least two DXA were included. Time to an event (osteopenia and osteoporosis) was assessed using the Kaplan-Meier method. Strata (tertiles) were defined using baseline minimum T scores. Differences between strata in time to an event were compared with the log-rank test.

RESULTS

Of 391 patients (1,639 DXAs), 49.6% had osteopenia and 21.7% osteoporosis at their first DXA scan. Of the 112 (28.6%) with normal BMD, 35.7% progressed to osteopenia; median progression time was 6.7 years. These patients were stratified: "low-risk" (baseline minimum T score >-0.2 SD), "middle-risk" (between -0.2 and -0.6 SD), and "high-risk" (from -0.6 to -1 SD); median progression time to osteopenia was 8.7, >7.2, and 1.7 years, respectively (p<0.0001). Of patients with osteopenia, 23.7% progressed to osteoporosis; median progression time was >8.5 years. Progression time was >8.2 years in "low-risk" tertile (T score between -1.1 and -1.6 SD), >8.5 years in "middle-risk" (between -1.6 and -2), and 3.2 years in "high-risk" (from -2 to -2.4) (p<0.0001).

CONCLUSIONS

Our results may help to define the BMD testing interval. The lowest T score tertiles would suggest recommending a subsequent DXA in 1-2 years; in the highest tertiles, ≥6 years. Early intervention in patients with bone demineralization could reduce fracture-related morbidity/mortality.

Low bone mass in behaviorally HIV-infected young men on antiretroviral therapy: Adolescent Trials Network Study 021B

BACKGROUND

Peak bone mass is achieved in adolescence/early adulthood and is the key determinant of bone mass in adulthood. We evaluated the association of bone mass with human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) during this critical period among behaviorally HIV-infected young men and seronegative controls.

METHODS

HIV-positive men (N = 199) and HIV-negative controls (N = 53), ages 14-25 years, were studied at 15 Adolescent Trials Network for HIV/AIDS Interventions sites. HIV-positive participants were recruited on the basis of ART status: ART-naive (N = 105) or on a regimen containing a nonnucleoside reverse transcriptase inhibitor (NNRTI; N = 52) or protease inhibitor (PI; N = 42). Bone mineral density (BMD) and content (BMC) and body composition were measured by dual-energy X-ray absorptiometry (DXA). Results were compared across groups by linear modeling. Bone results were adjusted for race, body mass index (BMI), and type of DXA (Hologic/Lunar).

RESULTS

The HIV-positive and HIV-negative groups had comparable median age (21 years) and racial/ethnic distribution. Median times since HIV diagnosis were 1.3, 1.9, and 2.2 years in the ART-naive, NNRTI, and PI groups, respectively (P = .01). Total and regional fat were significantly lower in the ART-naive group compared with seronegative controls. Mean BMD and Z scores were generally lower among HIV-positive participants on ART, particularly in the PI group. Average Z scores for the spine were below zero in all 4 groups, including controls.

CONCLUSIONS

Young men on ART with a relatively recent diagnosis of HIV infection have lower bone mass than controls. Longitudinal studies are required to determine the impact of impaired accrual or actual loss of bone during adolescence on subsequent fracture risk.

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.

[Consensus document of Gesida and Spanish Secretariat for the National Plan on AIDS (SPNS) regarding combined antiretroviral treatment in adults infected by the human immunodeficiency virus (January 2012)]

This consensus document has been prepared by a panel consisting of members of the AIDS Study Group (Gesida) and the Spanish Secretariat for the National Plan on AIDS (SPNS) after reviewing the efficacy and safety results of clinical trials, cohort and pharmacokinetic studies published in medical journals, or presented in medical scientific meetings. Gesida has prepared an objective and structured method to prioritise combined antiretroviral treatment (cART) in naïve patients. Recommendations strength (A, B, C) and the evidence which supports them (I, II, III) are based on a modification of the Infectious Diseases Society of America criteria. The current antiretroviral treatment (ART) of choice for chronic HIV infection is the combination of three drugs. ART is recommended in patients with symptomatic HIV infection, in pregnancy, in serodiscordant couples with high transmission risk, hepatitis B fulfilling treatment criteria, and HIV nephropathy. Guidelines on ART treatment in patients with concurrent diagnosis of HIV infection and an opportunistic type C infection are included. In asymptomatic patients ART is recommended on the basis of CD4 lymphocyte counts, plasma viral load and patient co-morbidities, as follows: 1) therapy should be started in patients with CD4 counts <350 cells/μL; 2) when CD4 counts are between 350 and 500 cells/μL, therapy will be recommended and only delayed if patient is reluctant to take it, the CD4 are stabilised, and the plasma viral load is low; 3) therapy could be deferred when CD4 counts are above 500 cells/μL, but should be considered in cases of cirrhosis, chronic hepatitis C, high cardiovascular risk, plasma viral load >10(5) copies/mL, proportion of CD4 cells <14%, and in people aged >55 years. ART should include 2 reverse transcriptase inhibitors nucleoside analogues and a third drug (non-analogue reverse transcriptase inhibitor, ritonavir boosted protease inhibitor or integrase inhibitor). The panel has consensually selected and given priority to using the Gesida score for some drug combinations, some of them co-formulated. The objective of ART is to achieve an undetectable viral load. Adherence to therapy plays an essential role in maintaining antiviral response. Therapeutic options are limited after ART failures, but an undetectable viral load may be possible nowadays. Adverse events are a fading problem of ART. Guidelines in acute HIV infection, in women, in pregnancy, and to prevent mother-to-child transmission and pre- and post-exposition prophylaxis are commented upon. Management of hepatitis B or C co-infection, other co-morbidities, and the characteristics of ART in HIV-2 infection are included.

Type 1 interferons suppress accelerated osteoclastogenesis and prevent loss of bone mass during systemic inflammatory responses to Pneumocystis lung infection

HIV infection causes loss of CD4(+) T cells and type 1 interferon (IFN)-producing and IFN-responsive dendritic cells, resulting in immunodeficiencies and susceptibility to opportunistic infections, such as Pneumocystis. Osteoporosis and bone marrow failure are additional unexplained complications in HIV-positive patients and patients with AIDS, respectively. We recently demonstrated that mice that lack lymphocytes and IFN a/b receptor (IFrag(-/-)) develop bone marrow failure after Pneumocystis lung infection, whereas lymphocyte-deficient, IFN α/β receptor-competent mice (RAG(-/-)) had normal hematopoiesis. Interestingly, infected IFrag(-/-) mice also exhibited bone fragility, suggesting loss of bone mass. We quantified bone changes and evaluated the potential connection between progressing bone fragility and bone marrow failure after Pneumocystis lung infection in IFrag(-/-) mice. We found that Pneumocystis infection accelerated osteoclastogenesis as bone marrow failure progressed. This finding was consistent with induction of osteoclastogenic factors, including receptor-activated nuclear factor-κB ligand and the proapoptotic factor tumor necrosis factor-related apoptosis-inducing ligand, in conjunction with their shared decoy receptor osteoprotegerin, in the bone marrow of infected IFrag(-/-) mice. Deregulation of this axis has also been observed in HIV-positive individuals. Biphosphonate treatment of IFrag(-/-) mice prevented bone loss and protected loss of hematopoietic precursor cells that maintained activity in vitro but did not prevent loss of mature neutrophils. Together, these data show that bone loss and bone marrow failure are partially linked, which suggests that the deregulation of the receptor-activated nuclear factor-κB ligand/osteoprotegerin/tumor necrosis factor-related apoptosis-inducing ligand axis may connect the two phenotypes in our model.

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.