Vitamin D deficiency and associated factors in hemodialysis patients.
ABSTRACT Vitamin D deficiency is prevalent in the general elderly population, and is related to an increased risk of osteoporosis, fractures, and cardiovascular calcification. Only limited data and no guidelines are available on vitamin D deficiency in hemodialysis patients.
We aimed to assess the frequency of, and factors associated with, 25(OH) vitamin D deficiency in hemodialysis patients in a French dialysis center.
In March 2006, we studied all prevalent hemodialysis patients who had not received native vitamin D supplements in the recent past. According to the Kidney Disease Outcomes and Quality Initiative guidelines, patients were assigned to the following 3 groups: group 1, with a sufficient vitamin D serum level (>75 nmol/L); group 2, with an insufficient level (25 to 75 nmol/L); and group 3, with severe deficiency (<25 nmol/L). Patients' characteristics and biochemical findings were compared between patients of groups 1 and 3.
Of 253 patients, 11% patients were in group 1; 47% were in group 2; and 42% were in group 3. The proportions of female and diabetes patients were 42% and 34%, respectively. The mean (+/- SD) age of all patients was 66.7 +/- 14 years, and the mean duration of dialysis was 62 +/- 74 months, with a mean schedule of 3 x 6.5 hours and administration of a 1.5 mmol/L calcium dialysate. Concomitant treatment included alfacalcidol (66% of patients) and sevelamer (34% of patients) as a standard phosphate binder. Group 3 patients had a lower dialysis vintage (53 +/- 66 vs. 73 +/- 85 months, P < .05), a higher number of diabetes patients (45% vs. 21%, P < .05), a higher number of female patients (53% vs. 28%, P < .05), and a higher level of intact parathyroid hormone (260 +/- 227 vs. 213 +/- 153 pg/mL, P < .05) than group 1 patients. No relationship was found between vitamin D storage levels and bone markers, serum calcium, phosphorus, albumin, body mass index, normalized protein catabolic rate, radiologic vascular calcification score, and hip bone mineral density. In multivariate logistic regression analyses, no factors were significantly associated with vitamin D deficiency.
Calcidiol deficiency was highly prevalent in a French dialysis population. The associated factors mainly included female sex, diabetes, shorter dialysis duration, and higher intact parathyroid hormone level. Although there are no guidelines for the therapy of patients with chronic kidney disease at stage 5, the usefulness of vitamin D supplementation may be assessed by considering its potential direct action, the need for providing fuel for renal and extrarenal calcitriol production in particular, and the numerous potential favorable effects on health.
Article: Vitamin D status in dark-skinned patients undergoing hemodialysis in a continually sunny country.[show abstract] [hide abstract]
ABSTRACT: Background: Vitamin D (vitD) insufficiency is common in end-stage renal disease. Seasonal and ethnic differences in vitD status have been reported previously. We hypothesized that vitD status in Afro-Caribbean patients on hemodialysis (HD) living in a country with a constant sunny climate would be better than that in African-American HD patients living in countries with a winter season. Method: A cross-sectional study was conducted in152 Afro-Caribbean HD patients in a dialysis center located in Guadeloupe. We evaluated the prevalence of vitD insufficiency, defined as serum 25-hydroxyvitamin D (25(OH)D) levels below 30 ng/mL, compared with those results previously reported in African-American HD patients (88%). Results: Prevalence of vitD insufficiency was 60% and thus lower than that in the African-American patients considered as the reference population (p<0.001). In our diabetic patients, this prevalence was 72.4%. Globally, 9.2% of patients had 25(OH)D below 15 ng/mL. Alfacalcidol therapy was prescribed in 29%. Mean 25(OH)D levels were higher in treated than in untreated patients (32 vs. 27 ng/mL; p=0.009). Patients with vitD insufficiency had dyslipidemia and diabetes more frequently. No significant differences were found between patients with and without vitD insufficiency for serum calcium, phosphorus and parathyroid hormone (PTH). In untreated patients, no significant correlation was found between 25(OH)D and PTH levels. Conclusion: Prevalence of vitD insufficiency in Afro-Caribbean HD patients was lower than that previously reported in African Americans undergoing HD in the United States. This finding may be due to the constantly sunny weather with a high intensity of UVB radiation in Guadeloupe.Journal of nephrology 01/2012; · 1.65 Impact Factor
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ABSTRACT: The discovery of fibroblast growth factor 23 (FGF23) as the causal factor in the pathogenesis of rare forms of hypophosphatemic rickets is rapidly reshaping our understanding of disordered mineral metabolism in chronic kidney disease (CKD). Excessive production of FGF23 by osteocytes is an appropriate compensation to help maintain normal phosphorus metabolism in these patients. Beginning in early CKD, progressive increases in levels of FGF23 enhance phosphaturia on a per-nephron basis and inhibit calcitriol production, thereby contributing centrally to the predominant phosphorus phenotype of predialysis kidney disease: normal serum phosphate, increased fractional excretion of phosphate, and calcitriol deficiency. A proliferation of studies linking phosphorus and now FGF23 excess to adverse renal and cardiovascular outcomes in patients with CKD is setting the stage for novel clinical trials that could ultimately bring FGF23 testing into the clinic. Ten burning questions must be addressed to galvanize FGF23 research further in CKD.Journal of the American Society of Nephrology 09/2010; 21(9):1427-35. · 9.66 Impact Factor
Article: Diagnostic Workup for Disorders of Bone and Mineral Metabolism in Patients with Chronic Kidney Disease in the Era of KDIGO Guidelines.[show abstract] [hide abstract]
ABSTRACT: KDIGO (KIDNEY DISEASE: Improving Global Outcomes) is an international nonprofit organization devoted to "improve the care and outcomes of kidney disease patients worldwide through promoting coordination, collaboration, and integration of initiatives to develop and implement clinical practice guidelines." The mineral and bone disorder (MBD) in patients with chronic kidney disease (CKD) has been the first area of interest of KDIGO international initiative. KDIGO guidelines on CKD-MBD were published in 2009 with the intent to modify the previous KDOQI guidelines that had failed to consistently change the global outcome of CKD patients. After the publication of KDOQI guidelines for bone metabolism and disease in 2003, a large number of observational data emerged in literature linking disordered mineral metabolism with adverse clinical outcomes. Notwithstanding this large body of observational data, a paucity of evidence from high-quality clinical trials was available for the development of KDIGO guidelines. Herein, a summary will be provided of the most important findings of KDIGO guidelines regarding the diagnostic workup and clinical monitoring of CKD-MBD patients.International journal of nephrology. 01/2011; 2011:958798.