Status of vitamin D and parameters of calcium homeostasis in renal transplant recipients in Nepal: a cross sectional study (original) (raw)
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Effects of vitamin D supplementation on the calcium–phosphate balance in renal transplant patients
Kidney International, 2009
Low serum levels of 25-hydroxy vitamin D frequently occur after renal transplantation, but few studies have evaluated the effects of normalizing this on serum parathyroid hormone and calcium levels or urinary calcium excretion. To determine this we compared the outcomes of 94 renal transplant patients with low 25-hydroxy vitamin D and normal serum calcium levels who were either treated or not with cholecalciferol every 2 weeks for 2 months (intensive phase) followed by an every other month maintenance phase. The biological characteristics of the two equally divided patient groups did not differ before treatment. After the intensive phase, serum 25-hydroxy vitamin D levels were normalized in all but 3 patients and the serum parathyroid hormone decreased and calcium levels increased with no severe adverse effects. During the maintenance phase, the serum 25-hydroxy vitamin D level decreased but remained significantly higher than in controls. In the control group, the serum 25-hydroxy vitamin D concentration increased slightly but became normal in only three patients. Serum 25-hydroxy vitamin D levels were significantly higher and parathyroid hormone levels were lower in treated patients compared to controls one year following transplant. Hence, cholecalciferol treatment significantly increased serum 25-hydroxy vitamin D and decreased parathyroid hormone levels with no adverse effects in 25-hydroxy vitamin D-deficient renal transplant patients.
Prevalence of vitamin D deficiency in post renal transplant patients
Indian Journal of Endocrinology and Metabolism, 2012
Aim: Deficiency of Vitamin D is prevalent in the general population, especially in Chronic Kidney Disease (CKD) patients. The exact prevalence of Vitamin D deficiency is unknown in post renal transplant recipients. The classical and non-classical effects of vitamin D deficiency are complicated by the use of steroids and calcineurin inhibitors (CNIs) in the renal transplant population. The aim of this study is to document the prevalence of Vitamin D deficiency in the post renal transplant population. Materials and Methods: A total of 51 renal transplant recipients under follow-up at Indraprastha Apollo Hospital, between June 2009 and March 2011, were enrolled in this study. Parathormone (PTH), 25(OH)-vitaminD3, calcium, and phosphate levels were determined in all the patients. The patients were then classified into different groups based on the severity of the Vitamin D deficiency, time since transplantation, and level of graft function. Results: Overall, four patients (8%) were vitamin D sufficient, 17 patients (33%) insufficient, 26 patients (51%) mildly deficient, and four (8%) severely deficient. The degree of deficiency did not differ with reference to the time since transplant or level of graft function. Sixty-nine percent had high PTH level, 22% were normal, and 9% had a low parathyroid hormone level. There was an inverse correlation between Vitamin D deficiency and serum PTH level. Conclusion: In this study, there was a high prevalence of vitamin D deficiency in renal transplant recipients. This did not get corrected, despite nutritional improvement or normalization of the glomerular filtration rate (GFR) post transplantation. Therefore, the study emphasizes routine evaluation and proper supplementation of Vitamin D in all post renal transplant patients.
Determinants of vitamin D status in long-term renal transplant patients
Clinical Transplantation, 2012
In this study, we explored the determinants of vitamin D status in a large cohort of stable, long-term renal transplant (RTx) patients. Serum 25(OH)D concentrations, and bone biochemistry parameters, were retrospectively analyzed from 266 RTx patients (>10 yr postengraftment) presenting to clinic over the course of a year. Forty-five percent of the cohort were vitamin D deficient (<37.5 nM), 38% insufficient (37.5 75-nM), and 17% sufficient (>75 nM). Serum 25(OH)D concentrations were higher in patients presenting in summer (p < 0.001) and in more active patients (p < 0.05). RTx patients with non-melanoma skin cancer (NMSC) (n = 45) had higher 25(OH)D concentrations than patients without NMSC (n = 221; p < 0.05) despite these patients being older, having worse eGFR, transplanted for longer, and less active physically (p < 0.05). Lower 25(OH)D concentrations were associated with higher PTH concentrations (p < 0.05) which, in the setting of widespread hypovitaminosis, suggests that secondary hyperparathyroidism was common in this cohort. In conclusion, season and activity status are important determinants of vitamin D status. We report, for the first time, that NMSC is associated with higher 25(OH)D, probably through increased UV radiation exposure. Long-term RTx patients may benefit from oral vitamin D supplementation, but this requires a randomized controlled trial to confirm.
The Relationship Between Vitamin D Status and Graft Function in Renal Transplant Recipients
International Journal of Medical Biochemistry, 2017
INTERNATIONAL JOURNAL OF MEDICAL BIOCHEMISTRY C hronic kidney disease (CKD), which has a high morbidity and mortality rate, negatively affects the quality of life. The incidence of the disease has increased significantly in recent years [1]. Renal replacement therapies, such as dialysis and renal transplantation, are implemented for patients with CKD. In renal transplantation patients, survival and quality of life is improved markedly compared with dialysis patients, and less cardiovascular disease is observed [2]. However, there is still a high risk for acute rejection and chronic allograft nephropathy in renal transplantation [3, 4]. Due to the increasing importance of the renal transplantation, it is very important to reduce major risk factors involved in graft failure. Vitamin D, which plays an important role in the regulation of calcium, phosphorus, and bone metabolism, is a steroid hormone. It is obtained through nutrition and solar radiation. Two hydroxylation steps are required to convert it to the physiologically active form of vitamin D (1,25-dihydroxyvitamin D, calcitriol). The first step occurs in the liver, producing 25-hydroxyvitamin D3 Objectives: Bone and mineral metabolism disorders are important potential complications after renal transplantation. The purpose of this study was to demonstrate the relationship between vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3], calcium, and phosphorus metabolism with graft function in renal transplant recipients. Methods: This prospective longitudinal study included 30 renal transplant recipients (10 female, 20 male; mean age: 40.30±12.86 years). Blood and urine samples were collected before and 6 months after transplantation. Serum creatinine, blood urea nitrogen (BUN), calcium, phosphorus, alkaline phosphatase (ALP), glucose, albumin, parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], and plasma 1,25(OH)2D3 levels were measured. In addition, the urine protein/creatinine (P/C) ratio was calculated. The plasma 1,25(OH)2D3 level was determined using liquid chromatography-tandem mass spectrometry. Results: The posttransplant level of serum phosphorus, PTH, creatinine, BUN and ALP was found to be significantly decreased (p=0.0001; p=0.011 for ALP). Although the plasma 1,25(OH)2D3 level had significantly increased (p=0.0001) after transplantation, no significant difference in the serum 25(OH)D level was observed. The urine P/C ratio was found to be significantly decreased after transplantation (p=0.007). A deficiency of vitamin D was observed frequently both before (87%) and after (73%) transplantation. Conclusion: Persistent vitamin D deficiency was detected in the recipients even after transplantation, although the serum PTH level decreased. Some studies published to date draw a direct link between serum vitamin D level and graft function; however, evidence for this link was not observed in the present study. Long-term monitoring may be needed to evaluate the correlation between vitamin D level and graft function.
Transplantation Proceedings, 2009
Introduction. The Kidney Disease Outcome Quality Initiative (K/DOQI) clinical practice guidelines in chronic kidney disease (CKD) give some recommendations about diagnosis and treatment of vitamin D deficiency. These guidelines may also be applied to renal transplant recipients. The aim of the present study was to assess the vitamin D status and the effects of vitamin D3 supplements among a cohort of kidney graft recipients. Patients and Methods. Five hundred nine renal transplant recipients with a follow-up of more than 12 months were included in this retrospective cross-sectional study. A total of 189 patients were treated with vitamin D3 supplements, 171 with calcitriol (0.25 or 0.5 g ϫ 3 weekly) and 18 with cholecalciferol (400 IU/d). Results. 25OHD deficiency was present in 38.3% of patients, insufficiency in 46.9%, and normal levels in 14.7%. There were no differences in the prevalence of deficiency or insufficiency between patients who were not treated or those who were treated with vitamin D3 supplements. Upon multivariate analysis, 25OHD concentrations correlated with gender, length of follow-up, season of 25OHD determination, iPTH and 1.25OHD concentrations, and treatment with ACEI/ARB (R 2 ϭ 0.17; P ϭ .000). Conclusions. 25OHD deficiency or insufficiency is frequent after renal transplantation even in sunny regions. The clinical significance of such a high prevalence of apparent 25OHD deficiency/insufficiency is unclear and requires further study.
Endocrine, 2015
Vitamin D deficiency is common among kidney transplant (KT) recipients because of reduced sunlight exposure, low intake of vitamin D, the immunosuppressive drug regimen administered, and steroid therapy. Glucocorticoids regulate expression of genes coding for enzymes that catabolize vitamin D, further reducing its level in serum. Although vitamin D primarily regulates calcium homeostasis, vitamin D deficiency is associated with the risk of several diseases, such as diabetes mellitus and tuberculosis. Aim of this review is to highlight endocrine and metabolic alterations due to the vitamin D deficiency by evaluating the mechanisms involved in the development of KT-related disease (cardiovascular, bone mineral density, and new-onset diabetes after transplantation). Next, we review evidence to support a link between low vitamin D status and KT-related diseases. Finally, we briefly highlight strategies for restoring vitamin D status in KT patients.
International Urology and Nephrology, 2018
Purpose CKD patients after kidney transplantation continue to suffer from elevated CV events which may be related to low vitamin D and its adverse impact on vascular function. The prevalence of vitamin D deficiency in North Indian kidney transplantation patients and its impact on vascular and bone biomarkers is unknown which this study investigated. Methods Non-diabetic, stable, > 6 months post-kidney transplantation patients, not on vitamin D supplementation, were recruited after informed consent. Data on demographics, anthropometrics and treatment were collected. Blood samples were stored at − 80 °C until analysis for bone and endothelial cell biomarkers using standard ELISA techniques. Results The clinical characteristics were: age 37.4 ± 9.9 years, 80% men, 27% ex-smokers, BP 125.5 ± 15.7/78.6 ± 9.7 mmHg, cholesterol 172.0 ± 47.8 mg/dL, hemoglobin 12.6 ± 2.3 g/dL, calcium 9.5 ± 0.6 mg/d and iPTH 58.4 ± 32.9 ng/mL and vitamin D 36.5 ± 39.8 nmol/L. Patients with vitamin D < 37.5 nmol/L (66%) had similar age, serum creatinine, serum phosphate, iPTH, blood pressure but lower calcium (9.3 ± 0.7 vs. 9.6 ± 0.5 mg/dL; p = 0.024), lower FGF23 (median 18.8 vs. 80.0 pg/mL; p = 0.013) and higher E-selectin (15.8 ± 7.9 vs. 13.0 ± 5.5 ng/mL; p = 0.047). On Univariate analysis, E-selectin (r = − 0.292; p = 0.005), FGF23 (r = 0.217; p = 0.036) and calcium (r = 0.238; p = 0.022) were significantly correlated with vitamin D levels. On stepwise multiple regression analysis, only E-selectin was associated with vitamin D levels (β = − 0.324; p = 0.002). Conclusion Vitamin D deficiency was common in kidney transplant recipients in North India, associated with low FGF23 and high E-selectin. These findings suggest further investigations to assess the role of vitamin D deficiency-associated endothelial dysfunction, its implications and reversibility in kidney transplantation recipients.
High Prevalence of Vitamin D Insufficiency in Southern Chinese Renal Transplant Recipients
Renal Failure, 2012
Vitamin D deficiency is common globally. There is evidence that vitamin D status may be related to immune function and cardiovascular disease. The vitamin D status of Chinese kidney transplant recipients has never been investigated. We performed a cross-sectional study and measured the level of 25-hydroxyvitamin D [25(OH)D] in 94 Chinese renal transplant recipients with stable allograft function. Vitamin D deficiency and insufficiency were detected in 43.6% and 54.2% of patients, respectively. About 53.2% of the patients also had elevated parathyroid hormone (PTH) levels. The level of 25(OH)D was lower in kidney transplant recipients compared with healthy controls matched for age and sex (52.5 AE 15.6 nmol/L vs. 57.5 AE 19.0 nmol/L, p ¼ 0.05), but the level of serum creatinine was higher in kidney transplant recipients (120.3 AE 48.5 μmol/L and 78.3 AE 15.3 μmol/L, p < 0.01). The level of 25(OH)D was negatively correlated with that of PTH (p ¼ 0.001). The latter was associated with serum creatinine (p ¼ 0.001) and duration of dialysis (p ¼ 0.001). Patients with a history of acute rejection showed lower levels of 25(OH)D (45.3 AE 11.9 nmol/L vs. 54.2 AE 16.0 nmol/L, p ¼ 0.003). We conclude that vitamin D deficiency is prevalent among Chinese renal transplant recipients. In view of the potential immunomodulatory effect of vitamin D, the relationship between vitamin D level and rejection and the effect of vitamin D supplementation in renal transplant recipients warrant further investigations.
Vitamin D Status, Bone Mineral Density, and Inflammation in Kidney Transplantation Patients
Transplantation Proceedings, 2009
Vitamin D has immunomodulatory and anti-inflammatory activities in the healthy population and in various disease states. There are few data on the quantification of vitamin D status and inflammation with respect to changes in bone mineral density among renal transplantation patients. We analyzed the influence of vitamin D levels on allograft function and inflammatory status at the time of enrollment and at 1-year follow-up. Sixty-four renal transplant patients, including 38 males, showed an overall age of 38.61 Ϯ 1.05 years, had a mean graft age of 6.15 Ϯ 3.17 years. We excluded patients who had diabetes mellitus, chronic inflammatory disease, or chronic allograft nephropathy. We obtained pre-and posttransplantation serum samples and daily proteinuria on each patient. Measurements of bone mineral density were performed by dual-energy X-ray absortiometry. After enrollment, we followed the patients for 1 year. Thereafter we assessed serum creatinine, C-reactive protein, albumin, and spot urinary protein levels. The patients were divided into two groups based upon vitamin D levels: group I (n ϭ 29), Ͻ20 g/L versus group II (n ϭ 35), Ն20 g/L. There was no significant difference in intact parathyroid hormone levels between the two groups. Vitamin D level positively correlated with serum creatinine (r ϭ .32, P ϭ .01) and serum albumin levels (r ϭ .28, P ϭ .023) at the time of enrollment. At 1 year, patients in group I showed significantly higher creatinine (P Ͻ .001) and proteinuria levels (P Ͻ .05) than those in group II. Low vitamin D levels are not uncommon among renal transplant recipients. There was a significant association of vitamin D levels with renal allograft function. Low vitamin D levels may be a predictor of worsening of graft function and increasing proteinuria.
Journal of Renal Injury Prevention
Introduction: Vitamin D deficiency can impact post-transplant outcomes due to its effect on graft function and rejection. The effect of pre-and post-transplant serum vitamin D levels was evaluated on graft function. Objectives: This study aims to determine the incidence of vitamin D deficiency and its effect on post kidney transplant allograft function in a North Indian cohort. Patients and Methods: We evaluated 57 patients on dialysis, going for transplantation. Estimated glomerular filtration rate (eGFR) was measured using modification of diet in renal disease (MDRD) formula at 2 weeks and 3, 6, 12 months interval after kidney transplantation. Results: Pre-and post-transplant (3 months) vitamin D levels were evaluated for vitamin D deficiency and graft function. Before transplant vitamin D levels were 25.77 ± 13.68 ng/mL, 40.4% of these recipients had vitamin D deficiency (levels <20 ng/mL). After transplant, vitamin D levels at 3 months were 22.08 ± 11.15 ng/mL and 54.4% of recipients had vitamin D deficiency. No patient was on vitamin D supplementation after transplantation. At 3 months post-transplant, recipients with vitamin D levels <20 ng/mL, had significantly lower eGFR and higher serum creatinine value as compared to the group with vitamin D levels >20ng/mL. Recipients were divided into 3 groups based on pre-and post-transplant vitamin D levels (<20, 20-30 and >30ng/mL). Pre-transplant vitamin D levels correlated with graft function at 14 days. On multiple regression analysis, 3-month post-transplant vitamin D levels correlated with 12 months eGFR. There was increased incidence of acute rejection episodes in vitamin D deficiency group. Conclusion: There is a high incidence of vitamin D deficiency and insufficiency in kidney transplant recipients. Low levels of post-transplant vitamin D levels at 3 months were associated with inferior allograft function (eGFR) at 1 year.