Luis Del Rio

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.

Body composition changes after switching from protease inhibitors to raltegravir: SPIRAL-LIP substudy.

Objective:To compare 48-week changes in body fat distribution and bone mineral density (BMD) between patients switching from a ritonavir-boosted protease inhibitor (PI/r) to raltegravir (RAL) and patients continuing with PI/r. Design:Substudy of the prospective, randomized, open-label, multicenter SPIRAL study. Methods:Patients were randomized (1 : 1) to continue with the PI/r-based regimen or switch to RAL, maintaining the rest of the treatment unchanged. Dual-energy X-ray absorptiometry and computed tomography scans were performed at baseline and after 48 weeks to measure body fat and bone composition, analyzing intragroup and intergroup differences. Results:Eighty-six patients were included and 74 patients (39 RAL, 35 PI/r) completed the substudy. Significant increases in median [interquartile range (IQR)] visceral adipose tissue (VAT) [20.7 (−2.4 to 45.6) cm2, P = 0.002] and total adipose tissue (TAT) [21.4 (−1.3 to 55.4) cm2, P = 0.013] were seen within the PI/r group. No significant changes in body fat were seen with RAL or between treatment groups. Regarding bone composition, total BMD [0.01 (0 to 0.02) g/cm2, P = 0.002], total hip BMD [0.01 (0 to 0.03) g/cm2, P = 0.015] and total hip T score [0.12 (−0.05 to 0.21) SD, P = 0.004] significantly increased with RAL, with no significant changes within the PI/r group. Differences between treatment groups were significant in femoral neck BMD [0.01 (−0.02 to 0.02) g/cm2, P = 0.032] and T score [0.01 (−0.18 to 0.18) SD, P = 0.016]. Conclusion:Although there were no significant changes in body fat between groups, maintaining a PI/r-based regimen was associated with a significant increase in VAT and TAT. Switching to RAL led to a significant increase in femoral neck BMD when comparing between groups.

How much fat loss is needed for lipoatrophy to become clinically evident

The objective of this study was to evaluate how much limb fat is needed to be lost for lipoatrophy to become clinically evident. Antiretroviral drug-naive patients from a randomized trial comparing stavudine or abacavir plus lamivudine and efavirenz, who had subjective assessment to detect clinically evident lipoatrophy (standardized questionnaire) and objective measurements of limb fat (dual X-ray absorptiometry) at baseline, 48 weeks, and 96 weeks were included. ROC curves were used to assess the sensitivity and specificity of several cut-off values of absolute and percent limb fat loss for diagnosing lipoatrophy. Of 54 patients included, 13 (24%) had subjective lipoatrophy at 96 weeks. After 96 weeks, median limb fat change was -2.3 kg (interquartile range: -5.2, +0.2) and 0.4 kg (interquartile range: -7.2, +3.4) in patients with and without lipoatrophy, respectively. Median percent limb fat change was -45.5% (interquartile range: -78.0, +3.7) and 5.5% (interquartile range: -62.8, +95.6), respectively. The cut-off values of absolute and percent limb fat loss showing the best sensitivity and specificity values were -1.5 kg (sensitivity, 77%; specificity, 76%) and -30% (sensitivity, 85%; specificity, 73%). At least 30% limb fat is needed to be lost in HIV-infected patients for lipoatrophy to become clinically evident.

Fat Tissue Measurements by Dual-Energy X-Ray Absorptiometry: Cross-Calibration of 3 Different Fan-Beam Instruments

Analysis of total tissue composition and, particularly, body fat measurements has become progressively important in the diagnosis and follow-up of patients with different clinical conditions. Dual-energy X-ray absorptiometry (DXA) fan-beam scanners are widely used to measure body composition, but the development of translational equations to be able to compare data of different scanning systems is necessary. The aim of this study was to assess the extent of agreement for regional measurements of body composition among the following 3 fan-beam DXA scanners: (1) Hologic Discovery (Hologic, Inc., Waltham, MA), (2) Lunar iDXA (GE Healthcare, Madison, WI), and (3) Lunar Prodigy Advance (GE Healthcare, Madison, WI). The study population consisted of 91 adult healthy volunteers (40 males and 51 females; mean age 48.5±14.4yr) who underwent DXA evaluation of the lumbar spine, hip, and whole body in each machine on the same day. Agreement among the 3 scanners was evaluated according to the Bland-Altman method and Lins concordance correlation coefficient. Results showed a better agreement and concordance for the Lunar iDXA scanner than for any of them with the Hologic scanner. Differences were higher for any tissue or region than for the whole tissue mass. Translational equations were developed to ensure comparability of body composition measurements obtained with each of these 3 scanners.

Validation of the FRAX Predictive Model for Major Osteoporotic Fracture in a Historical Cohort of Spanish Women

FRAX is a fracture risk assessment tool to estimate the 10-yr probability of a major osteoporotic fracture or a hip fracture. The aim of the study was to assess the predictive ability of FRAX for major osteoporotic fracture in a cohort of Spanish women. The study was based on a retrospective cohort of women aged 40-90 yr. Patients were followed from their first bone densitometry to the first major osteoporotic fracture event (forearm, proximal humerus, clinical spine, or hip fracture) or for 10 yr whichever comes first. A total of 1231 women were included. Bone mineral density data and self-reported data on risk factors for fracture were obtained. The predictive ability of FRAX was assessed by analyzing calibration and discrimination, with the calculation of observed-to-expected (O/E) fracture ratios and the receiver operating characteristic (ROC) curve, respectively. A total of 222 women (18.1%) reported at least 1 fracture after the first assessment. The incidence of fracture was 14 (95% confidence interval [CI]: 10-17), 19 (95% CI: 15-23), 28 (95% CI: 21-36), and 67 (95% CI: 8-125) cases per 1000 woman-years in women aged <55, 55-64, 65-74, and ≥75 yr, respectively. The O/E ratio was 3.9 (95% CI: 3.4-4.5; p<0.0001). The area under the ROC curve was 61% (95% CI: 57-65%). FRAX underestimated the risk of major osteoporotic fracture in this cohort of Spanish women, particularly in those with a low risk of fracture according to the clinical factors used in the FRAX tool. Our findings highlight the need for validation studies of FRAX in Spain.

Factores de riesgo de fracturas por fragilidad en una cohorte de mujeres españolas

INTRODUCTION Fragility fractures are an important public health issue. The aim of this study was to analyze the association of the main osteoporotic risk factors related to fragility fracture in a cohort of women with an indication of bone densitometry (BD). METHODS A retrospective cohort was followed-up until a fragile fracture occurred, in a population of women aged 40 to 90 years with a first visit for BD between January 1992 and February 2008. We calculated the incidence rate of fracture per 1000 women-years of follow-up, and the hazard ratio (HR) of fragile fracture using a Cox regression model. RESULTS A total of 49,735 women were studied. The average age of participants was 57.8 years (SD: 8.5). Of these, 3631 women (7.1%) reported a new fragility fracture in post-baseline visits. Risk factors with higher adjusted HR were age ≥ 75 years compared with age < 55 years (HR: 3.8; 95% CI: 3.3-4.4) and having a BC result evaluated as osteoporosis compared to normal (HR: 2.0; 95% CI: 1.8-2.2). A personal history of humerus, hip or vertebral fractures had an adjusted HR of 1.2 (95% CI: 1.1-1.3). CONCLUSIONS The main risk factors for fragility fracture were advanced age, BD result and a personal history of fracture, although 74% of fractures were detected with a bone mineral density classified as normal or osteopenia. Other relevant factors were rheumatoid arthritis or having received prolonged corticosteroid therapy.

Effects of Switching from Stavudine to Raltegravir on Subcutaneous Adipose Tissue in HIV-Infected Patients with HIV/HAART-Associated Lipodystrophy Syndrome (HALS). A Clinical and Molecular Study

HIV-1/HAART-associated lipodystrophy syndrome (HALS) has been associated with exposure to stavudine (d4T) through mitochondrial dysfunction. We performed a 48-week study to assess the effects of switching from d4T to raltegravir (RAL) on metabolic and fat molecular parameters of patients with HALS. Forty-two patients with HALS and a median exposure to d4T > 7 years were switched to RAL and followed for 48 weeks. Fasting metabolic tests, HIV RNA, CD4 cell count, and fat measured by DEXA were obtained at baseline and week 48. mtDNA and gene transcripts for PPAR gamma, adiponectin, cytochrome b, Cox IV, TNF alpha, MCP-1 and CD68 were assessed in paired subcutaneous fat tissue biopsies. Lipid parameters, fasting glucose, insulin, and HOMA-IR did not change significantly. Whole body fat (P = 0.0027) and limb fat mass (P<0.0001) increased from baseline. Trunk/limb fat ratio (P = 0.0022), fat mass ratio (P = 0.0020), fat mass index (P = 0.0011) and percent leg fat normalized to BMI (P<0.0001) improved after 48 weeks. Relative abundance of mtDNA, expression of PPAR gamma, adiponectin, Cyt b, and MCP-1 genes increased, whereas Cox IV, TNF alpha, and CD68 did not change significantly from baseline. Switching from d4T to RAL in patients with HALS is associated with an increase in limb fat mass and an improvement in markers of adipocyte differentiation and mitochondrial function in SAT.

Effects of testosterone treatment on body composition in males with testosterone deficiency syndrome

Abstract Objective: We evaluated the safety of testosterone treatment and its efficacy on body composition in males with testosterone deficiency syndrome (TDS) over 24 months. Methods: 50 males aged 50–65 years with TDS (Aging Males Symptoms Scale [AMS] > 26 and calculated free testosterone [cFT] 250 pmol/l) were administered 50 mg testosterone gel daily for one year. During the second year, patients received 1000 mg of testosterone undecanoate every 2–3 months. Outcome measures were clinical chemistry values and total testosterone; sex hormone-binding globulin and cFT, changes in AMS and International Prostate Symptom Score; and changes in body composition measured by dual-energy-x-ray absorptiometry. Results: There were no clinically significant changes in clinical chemistry safety parameters. There were significant improvements in both total and cFT and in AMS scores after three months (p < 0.001). Lean mass increased 2.35% at 12 months and 4.5% at 24 months, but proportionally more muscle mass was gained in arms and legs than in the trunk. Fat mass decreased 4.2% at 12 months and 9.1% at 24 months. Conclusions: Testosterone treatment in males with TDS leads to body changes affecting lean and fat mass with significant improvement in AMS scores, and has an excellent safety profile.

Prevalence of vertebral fracture in postmenopausal women with lumbar osteopenia using MorphoXpress® (OSTEOXPRESS Study).

Background and aims: Vertebral fracture (VF) is the most common complication of osteoporosis. However, more than half of all VF are asymptomatic and may go unnoticed, even in patients with osteoporosis. Our aim was to assess the prevalence of VF in postmenopausal women with osteopenic lumbar densitometry by means of vertebral morphometry, using the MorphoXpressSR software. Patients and methods: This was an epidemiological, cross-sectional, multicenter study conducted among 289 postmenopausal women (>1 year of amenorrhoea), diagnosed with lumbar osteopenia (not due to chronic treatment with corticosteroids or immobilization). Vertebral deformities ≥20% were considered as VF. Results: Demographic and clinical characteristics showed mean age (±SD) 64±9 years, body mass index 27±5 kg/m2, and time from diagnosis of 2±3 years. A total of 25% of subjects had a family history of osteoporotic fracture in first-degree relatives, and 23% had previous fragility fracture. The prevalence of VF was 50% (CI 95% 44–56), the most frequent being the dorsal wedge (34%). Previous fragility fracture was a risk factor for VF (OR 3.13, p=0.0004). A total of 76.5% of patients were receiving treatment, mainly calcium and vitamin D supplements (70%) and bisphosphonates (27%). Conclusions: MorphoXpressSR revealed that 50% of postmenopausal women with osteopenic lumbar densitometry showed VF. This result is important since only 7% of all evaluated subjects had previously been diagnosed with VF.

The Search for a New Marker of Renal Function in Older Patients with Chronic Kidney Disease Stages 3–4: Usefulness of Cystatin C-Based Equations

Background/Aim: Cystatin C (Cys C) is an endogenous marker of glomerular filtration rate (GFR) unaffected by body composition. The aim of the present study was to assess the utility of Cys C-based GFR prediction equations (Hoek, Larsson and Stevens) and creatinine (modification of diet in renal disease-isotope dilution mass spectrometry – MDRD-IDMS, and Cockcroft-Gault – CG) compared with 51Cr-EDTA. Methods: This study was carried out in 40 Caucasian older patients with advanced age (≥60) and chronic kidney disease stages 3–4. To assess the utility of prediction equations in relation to body composition, we measured lean mass (LM) with densitometry (DXA). Pearson’s, Bland-Altman and Lin’s coefficient (Rc) were used to study accuracy and precision. Results:51Cr-EDTA was 36.9 ± 9.2 ml/min/1.73 m2 (22–60). Cys C levels were 2.2 ± 0.8 mg/l (r = 0.085; p = 0.662 LM) and creatinine 2.8 ± 1.1 mg/dl (r = 0.427; p = 0.021 LM). The most accurate equations were the Hoek, Larsson and Stevens formulae, with a bias of –0.2 (Rc 0.48), –2.9 (Rc 0.44) and 2.6 ml/min/1.73 m2 (Rc 0.58). The biases obtained with MDRD-IDMS and CG were –14.6 (Rc 0.35) and –12.5 (Rc 0.40). All correlations among biases obtained with creatinine-based formulae and LM were negative and statistically significant (p < 0.05). Conclusions: The results show superiority of Cys C-based GFR formulae over the MDRD-IDMS and CG equations. This significant underestimation obtained with conventional prediction equations was directly related to the influence of LM.