Mortality in Hemodialysis Patients with COVID-19, the Effect of Paricalcitol or Calcimimetics.

BACKGROUND: In COVID-19 patients, low serum vitamin D (VD) levels have been associated with severe acute respiratory failure and poor prognosis. In regular hemodialysis (HD) patients, there is VD deficiency and markedly reduced calcitriol levels, which may predispose them to worse outcomes of COVID-19 infection. Some hemodialysis patients receive treatment with drugs for secondary hyperparathyroidism, which have well known pleiotropic effects beyond mineral metabolism. The aim of this study was to evaluate the impact of VD status and the administration of active vitamin D medications, used to treat secondary hyperparathyroidism, on survival in a cohort of COVID-19 positive HD patients. METHODS: A cross-sectional retrospective observational study was conducted from 12 March to 21 May 2020 in 288 HD patients with positive PCR for SARS-CoV2. Patients were from 52 different centers in Spain. RESULTS: The percent of HD patients with COVID-19 was 6.1% (288 out of 4743). Mortality rate was 28.4% (81/285). Three patients were lost to follow-up. Serum 25(OH)D (calcidiol) level was 17.1 [10.6-27.5] ng/mL and was not significantly associated to mortality (OR 0.99 (0.97-1.01), p = 0.4). Patients receiving active vitamin D medications (16/94 (17%) vs. 65/191(34%), p = 0.003), including calcimimetics (4/49 (8.2%) vs. 77/236 (32.6%), p = 0.001), paricalcitol or calcimimetics (19/117 (16.2%) vs. 62/168 (36.9%); p < 0.001), and also those on both paricalcitol and calcimimetics, to treat secondary hyperparathyroidism (SHPTH) (1/26 (3.8%) vs. 80/259 (30.9%), p < 0.001) showed a lower mortality rate than patients receiving no treatment with either drug. Multivariate Cox regression analysis confirmed this increased survival. CONCLUSIONS: Our findings suggest that the use of paricalcitol, calcimimetics or the combination of both, seem to be associated with the improvement of survival in HD patients with COVID-19. No correlation was found between serum VD levels and prognosis or outcomes in HD patients with COVID-19. Prospective studies and clinical trials are needed to support these findings.

High Serum Retinol as a Relevant Contributor to Low Bone Mineral Density in Postmenopausal Osteoporotic Women.

There is controversial information about the impact of vitamin A on bone. Some epidemiological studies show that excessive intake of vitamin A, or an excess of serum vitamin A, has related with adverse impact on bone mass; however, other studies did not find these links, and some authors have proposed that this vitamin might promote a better bone health. The present work aims to contribute to clarify the real role of vitamin A in bone tissue. For this purpose, a cross-sectional study of 154 osteoporotic non-treated postmenopausal women (> 65 years old) was carried out. Bone mineral density (BMD) was measured by dual-energy X-ray absorptiometry. We assessed concentrations of serum retinol, osteocalcin, parathyroid hormone, alkaline phosphatase, calcium, and phosphorus. We also studied demographic and anthropometric parameters. Spearman's correlations between retinol levels and other variables found negative correlations with BMD in both lumbar spine (R = - 0.162, P < 0.01) and femoral neck (R = - 0.182, P < 0.01), as well as alkaline phosphatase (R = - 0.110; P < 0.05) and phosphorus (R = - 0.110; P < 0.05). A positive correlation between retinol and fertile window was observed (R = 0.158; P < 0.01). After multivariable adjustment, we still found a negative correlation between serum retinol and BMD, both at the lumbar spine (R = - 0.210; P < 0.01) and at the femoral neck (R = - 0.324, P < 0.001). It is concluded that elevated serum-retinol levels are associated with an increased risk of low bone mass and thus with osteoporotic fractures. Therefore, osteoporosis-risk assessment should include quantification of serum metabolite of vitamin A.

Low calcium intake and inadequate vitamin D status in postmenopausal osteoporotic women.

UNLABELLED: An observational cross-sectional study was conducted to assess calcium intake and vitamin D status by measurement of 25-hydroxyvitamin D (25(OH)D), in postmenopausal osteoporotic women (PMOW) treated and untreated for osteoporosis. To assess the influence of sunlight exposure on vitamin D status, the study group was categorized on the basis of sunlight exposure (above or below 2500 sunlight h/year). A group of 336 PMOW older than 65 years was identified (190 [56.5%] treated and 146 [43.5%] untreated for osteoporosis). The demographic and clinical data of the PMO women included history of prior fractures, pharmacological treatments and dietary calcium intake. BMD was measured by DEXA and 25(OH)D was determined by an HPLC method. RESULTS: vitamin D serum levels were lower in the untreated group as compared with the treated group (58±27 vs. 67±27nmol/l; p=0.006). Prevalence of vitamin D deficiency (cut-off point set at <50nmol/l) was higher in the non-treated group (43.8% vs. 29.5%; p=0.009). Nearly all PMOW, whether treated or not for osteoporosis had a total calcium intake of less than 1200mg. Sunlight exposure did not influence the vitamin D status. CONCLUSIONS: vitamin D deficiency and an insufficient calcium intake are highly prevalent in both treated and untreated Spanish PMOW older than 65 years. This can be related to low therapeutic adherence and/or insufficient prescription. Therefore physician's and patient's knowledge regarding the optimization of vitamin D status and calcium intake should be improved and implemented. This article is part of a Special Issue entitled 'Vitamin D workshop'.

The tissue diagnostic instrument.

Tissue mechanical properties reflect extracellular matrix composition and organization, and as such, their changes can be a signature of disease. Examples of such diseases include intervertebral disk degeneration, cancer, atherosclerosis, osteoarthritis, osteoporosis, and tooth decay. Here we introduce the tissue diagnostic instrument (TDI), a device designed to probe the mechanical properties of normal and diseased soft and hard tissues not only in the laboratory but also in patients. The TDI can distinguish between the nucleus and the annulus of spinal disks, between young and degenerated cartilage, and between normal and cancerous mammary glands. It can quantify the elastic modulus and hardness of the wet dentin left in a cavity after excavation. It can perform an indentation test of bone tissue, quantifying the indentation depth increase and other mechanical parameters. With local anesthesia and disposable, sterile, probe assemblies, there has been neither pain nor complications in tests on patients. We anticipate that this unique device will facilitate research on many tissue systems in living organisms, including plants, leading to new insights into disease mechanisms and methods for their early detection.