Renata Caudarella

Ultrasound in the evaluation of osteoporosis: a comparison with bone mineral density at distal radius

It is proven that, from a technical point of view, ultrasound transmission velocity (UTV) measurement can easily be taken at the distal end of the radius. The reproducibility of UTV is good (coefficient of variation 0.3% intraoperator and 0.5% interoperator). 248 normal and 65 osteoporotic women were then studied to establish the range of UTV values and to compare the ability of UTV and bone mineral density (BMD) measurement, taken at the same skeletal sites, to detect osteoporotic fragility. Osteoporosis was defined by the presence of atraumatic vertebral fractures on an X-ray of the spine. Ultrasound velocity averaged 1570.5 +/- 43.3 m s-1 in normal and 1519.2 +/- 15.2 m s-1 in osteoporotic women; the difference is also statistically significant (p < 0.01) for BMD. Both BMD and UTV decline after menopause and are significantly correlated with age. A weak correlation (r = 0.68) was found between UTV and BMD; this supports the thesis that ultrasound velocity measures bone mass as well as other fragility components of bone distinct from the decrease of mass. Receiver operating characteristic (ROC) curve analysis showed that UTV discriminates between normal and osteoporotic patients at least as well as radial BMD, indicating that UTV is a new available diagnostic modality which can be used to screen osteoporotic subjects.

Bone Mass Loss in Patients With Human Immunodeficiency Virus Type 1 Infection: Association With Male Sex and Protease Inhibitor Therapy

The aim of our study was to evaluate the prevalence of osteopenia/osteoporosis in patients with human immunodeficiency virus (HIV) type 1 infection and to assess their possible correlation with antiretroviral therapy. Patients were enrolled among adult subjects with HIV type 1 infection referring to our tertiary care outpatient center. Bone mineral density was measured in the lumbar spine and femoral proximal head by dual-energy x-ray absorptiometry. A total of 95 HIV-infected patients (45 men) were enrolled: 12 subjects were naive to antiretroviral therapy, 18 received 3 nucleoside reverse-transcriptase inhibitors (NRTIs), 28 were treated with 2 NRTIs plus 1 non-NRTI, and 37 received 2 NRTIs plus 1 protease inhibitor (PI). Prevalence of osteopenia and osteoporosis according to lumbar T score was 37.9% and 9.5%, respectively, and osteoporosis was significantly more frequent in men than in women (20% vs. 0%; P < 0.001). The mean value of lumbar T score was significantly lower in PI-treated patients (−1.32 ± 0.48) than in naive subjects (−0.62 ± 0.24) or in those receiving 3 NRTIs (−0.68 ± 0.34) or 1 non-NRTI (−0.86 ± 0.44) (P < 0.05). Bone metabolism alterations associated with HIV infection probably have a multifactorial pathogenesis, but in our study, bone mass loss seems prompted by the male sex and a PI-based therapy.

Potassium Citrate Supplementation Decreases the Biochemical Markers of Bone Loss in a Group of Osteopenic Women: The Results of a Randomized, Double-Blind, Placebo-Controlled Pilot Study

The relationship involving acid-base imbalance, mineral metabolism and bone health status has previously been reported but the efficacy of the alkalizing supplementation in targeting acid overload and preventing bone loss has not yet been fully elucidated. In this randomized, double-blind, placebo-controlled study, the hypothesis that potassium citrate (K citrate) modifies bone turnover in women with postmenopausal osteopenia was tested. Three hundred and ten women were screened; 40 women met the inclusion criteria and were randomly assigned to the treatment or the placebo group. They were treated with K citrate (30 mEq day−1) or a placebo in addition to calcium carbonate (500 mg day−1) and vitamin D (400 IU day−1). At baseline and time points of 3 and 6 months, serum indicators of renal function, electrolytes, calciotropic hormones, serum bone turnover markers (BTMs) (tartrate-resistant acid phosphatase 5b (TRACP5b), carboxy-terminal telopeptide of type I collagen (CTX), bone alkaline phosphatase (BAP), procollagen type 1 N terminal propeptide (PINP)), and urine pH, electrolytes, and citrate were measured. The follow-up was completed by 17/20 patients in the “K citrate” group and 18/20 patients in the “placebo” group. At baseline, 90% of the patients exhibited low potassium excretion in 24 h urine samples, and 85% of cases had at least one urine parameter associated with low-grade acidosis (low pH, low citrate excretion). After treatment, CTX and BAP decreased significantly in both groups, but subjects with evidence of low-grade acidosis gained significant benefits from the treatment compared to the placebo. In patients with low 24h-citrate excretion at baseline, a 30% mean decrease in BAP and CTX was observed at 6 months. A significant reduction was also evident when low citrate (BAP: −25%; CTX: −35%) and a low pH (BAP: −25%; CTX: −30%) were found in fasting-morning urine. In conclusion, our results suggested that K citrate supplementation improved the beneficial effects of calcium and vitamin D in osteopenic women with a documented potassium and citrate deficit, and a metabolic profile consistent with low-grade acidosis.

The Trabecular Bone Score Predicts Spine Fragility Fractures in Postmenopausal Caucasian Women Without Osteoporosis Independently of Bone Mineral Density

Introduction The trabecular bone score (TBS) is a gray-level textural metric that can be extracted from the two-dimensional lumbar spine dual-energy X-ray absorptiometry (DXA) image. TBS is related to bone microarchitecture. Several literature data suggest that TBS predicts fracture risk as well as lumbar spine bone mineral density (LS-BMD) measurements in postmenopausal women. Objective A retrospective case-control study assessing the ability of the TBS to predict spine fragility fractures (SFF) in postmenopausal women with or without osteoporosis (diagnosed by T-score≤-2.5). Methods LS-BMD and the TBS were determined in the L1-L4 vertebrae. Statistical analyses were carried out in the entire group of women (entire-group) (n.699), in women both with osteoporosis (osteoporosis-subgroup) (n.253) and those without osteoporosis (non-osteoporosis-subgroup) (n. 446). Results At the unpaired t-test, both the TBS and the LS-BMD (p≤0.001) were lower in women with SFF (n.62) in the entire-group. In the non-osteoporosis subgroup, the TBS (p≤0.009) was lower in women with SFF (n.29). In the osteoporosis subgroup, the LS-BMD (p≤0.003) was lower in women with SFF (n.33). Considering the TBS and LS-BMD separately in a block logistic regression, the TBS was associated with SFF in the entire-group (odds ratio (OR): 1.599, 95% confidence interval (CI): 1.021-2.128) and in the non-osteoporosis-subgroup (OR: 1.725, 95% CI:1.118-2.660) whereas LS-BMD was associated with SFF in the entire-group (OR: 1.611, 95% CI: 1.187-2.187) and in the osteoporosis-subgroup (OR: 2.383, 95% CI: 1.135-5.003). According to forward logistic regression, entering the TBS, LS-BMD and confounders as predictors, the LS-BMD in the entire-group (OR: 1.620, 95% CI: 1.229-2.135) and in the osteoporosis subgroup (OR: 2.344, 95% CI: 1.194-4.600), and the TBS in the non-osteoporosis subgroup (OR: 1.685, 95% CI: 1.131-2.511) were the only predictors of SFFs. Conclusions In the entire-group, the TBS predicted SFFs almost as well as LS-BMD, but not independently of it. The TBS, but not LS-BMD, predicted SFFs in the non-osteoporosis subgroup.

The Effect of Thiazides on Bone Markers, Bone Mineral Density and Fractures

Abstract The literature data suggest a positive effect of thiazide diuretic treatment on bone health both by increasing bone mineral density and by decreasing the risk of fracture. The protective effect of thiazides seems to be linked both to the dosage and to the duration of treatment; moreover, the protective effects of thiazides in preserving bone mass and in decreasing the risk of fractures does not last long after discontinuation of treatment. Thiazides influence bone health by means of different mechanisms. In fact, they increase renal calcium reabsorption by inhibiting the sodium chloride cotransporter in the distal tubule, thus increasing sodium urinary excretion and decreasing urinary calcium excretion. Still, thiazides contribute to maintaining calcium homeostasis by increasing calcium intestinal absorption. Moreover, thiazides have a direct effect on bone cells, especially on osteoblast differentiation and bone mineral formation. Finally, it was suggested that thiazides prevent bone loss as they decrease the acid production by means of inhibition of carbonic anhydrase activity in the osteoclasts. The dual action shown by thiazides on both osteoblasts and osteoclasts could explain the reduced bone remodeling observed in patients taking these drugs, in the absence of changes in plasma parathyroid hormone levels. In conclusion, thiazides might play an interesting role in osteoporosis management, particularly in those patients affected by both hypertension and osteoporosis, but efficacy in reducing fractures and the safety of this treatment must still be evaluated by means of further randomized controlled clinical trials which have the reduction in fractures as primary outcomes.

Osteopatie metaboliche nelle malattie renali

Le alterazioni del metabolismo minerale e del tessuto osseo rappresentano una complicazione comune nella storia naturale di numerose nefropatie, e trovano la loro espressione piu tipica nei pazienti con insufficienza renale cronica in fase uremica (IRC). La comparsa di osteopatie metaboliche nei pazienti nefropatici e la conseguenza del ruolo chiave svolto dal rene nella regolazione dell’omeostasi minerale; infatti esso modula l’equilibrio esterno di calcio, fosforo e magnesio, controlla la sintesi di 1,25(OH)2D3, degrada e rimuove dal circolo l’ormone paratiroideo (PTH), contribuisce alla regolazione dell’equilibrio acido—base ed e il principale responsabile dell’escrezione di alluminio.