Determinants of vitamin <scp>D</scp> status in long‐term renal transplant patients

Penny, Hugo A; Frame, Sharon; Dickinson, F.; Garrett, Giorgia L.; Young, Antony R.; Sarkany, Robert; Chitalia, Nihil; Hampson, Geeta; Goldsmith, David

doi:10.1111/ctr.12039

Cited by 19 publications

(11 citation statements)

References 30 publications

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“…Time from transplantation seems to positively influence 25-OH-D level in which every year out of transplantation decreases the risk of deficiency by approximately 10% [27] . In addition to the reduced sunlight exposure, the use of sun protectors, and the impaired kidney function, the use of immunosuppressive drugs especially high doses of steroid, and the presence of metabolic syndrome and obesity are also associated with 25OHD deficiency [26,28] ; Lower 25OHD level in KT recipients can worsen the degree of hyperparathyroidism by depleting the substrate for 1,25dihydroxyvitamin D (1,25OH2D) production [25] . Severe 1,25OH2D deficiency can be observed in up to 80% in the immediate posttransplant period [29] .…”

Section: Vitamin Dmentioning

confidence: 99%

Mineral and bone disorder after kidney transplantation

Taweesedt

Disthabanchong

2015

WJT

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After successful kidney transplantation, accumulated waste products and electrolytes are excreted and regulatory hormones return to normal levels. Despite the improvement in mineral metabolites and mineral regulating hormones after kidney transplantation, abnormal bone and mineral metabolism continues to present in most patients. During the first 3 mo, fibroblast growth factor-23 (FGF-23) and parathyroid hormone levels decrease rapidly in association with an increase in 1,25-dihydroxyvitamin D production. Renal phosphate excretion resumes and serum calcium, if elevated before, returns toward normal levels. FGF-23 excess during the first 3-12 mo results in exaggerated renal phosphate loss and hypophosphatemia occurs in some patients. After 1 year, FGF-23 and serum phosphate return to normal levels but persistent hyperparathyroidism remains in some patients. The progression of vascular calcification also attenuates. High dose corticosteroid and persistent hyperparathyroidism are the most important factors influencing abnormal bone and mineral metabolism in long-term kidney transplant (KT) recipients. Bone loss occurs at a highest rate during the first 6-12 mo after transplantation. Measurement of bone mineral density is recommended in patients with estimated glomerular filtration rate > 30 mL/min. The use of active vitamin D with or without bisphosphonate is effective in preventing early post-transplant bone loss. Steroid withdrawal regimen is also beneficial in preservation of bone mass in long-term. Calcimimetic is an alternative therapy to parathyroidectomy in KT recipients with persistent hyperparathyroidism. If parathyroidectomy is required, subtotal to near total parathyroidectomy is recommended. Performing parathyroidectomy during the waiting period prior to transplantation is also preferred in patients with severe hyperparathyroidism associated with hypercalcemia.

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Section: Vitamin Dmentioning

confidence: 99%

Mineral and bone disorder after kidney transplantation

Taweesedt

Disthabanchong

2015

WJT

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“…Among patients undergoing KT, studies have been conducted during different periods of the year, making it difficult to know whether they follow the trend observed in the general population. The literature commonly describes parathyroid hormone stimulation due to 25(OH)D deficiency during the earliest periods after KT as a consequence of the high doses of corticosteroids and persistent elevation of phosphatonins 6,18,19. Some authors have also found this correlation during later periods of KT recovery 7,20.…”

Section: Discussionmentioning

confidence: 99%

“…This radiation is clearly the most important physical environmental carcinogen for the development of skin cancer, and non-melanoma skin cancer (NMSC) is the most common malignancy among patients undergoing KT 23,24. The risk of developing this complication is associated with the duration and intensity of immunosuppression and cumulative sun exposure 18. However, some guidelines suggest that sunlight exposure for short periods of time is beneficial and does not increase the risk of skin cancer 25,26.…”

Section: Discussionmentioning

confidence: 99%

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Hypovitaminosis D in patients undergoing kidney transplant: the importance of sunlight exposure

Vilarta¹,

Unger²,

Reis³

et al. 2017

Clinics

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OBJECTIVES:Recent studies have shown a high prevalence of hypovitaminosis D, defined as a serum 25-hydroxyvitamin D level less than 30 ng/ml, in both healthy populations and patients with chronic kidney disease. Patients undergoing kidney transplant are at an increased risk of skin cancer and are advised to avoid sunlight exposure. Therefore, these patients might share two major risk factors for hypovitaminosis D: chronic kidney disease and low sunlight exposure. This paper describes the prevalence and clinical characteristics of hypovitaminosis D among patients undergoing kidney transplant.METHODS:We evaluated 25-hydroxyvitamin D serum levels in a representative sample of patients undergoing kidney transplant. We sought to determine the prevalence of hypovitaminosis D, compare these patients with a control group, and identify factors associated with hypovitaminosis D (e.g., sunlight exposure and dietary habits).RESULTS:Hypovitaminosis D was found in 79% of patients undergoing kidney transplant, and the major associated factor was low sunlight exposure. These patients had higher creatinine and intact parathyroid hormone serum levels, with 25-hydroxyvitamin D being inversely correlated with intact parathyroid hormone serum levels. Compared with the control group, patients undergoing kidney transplant presented a higher prevalence of 25-hydroxyvitamin D deficiency and lower serum calcium, phosphate and albumin but higher creatinine and intact parathyroid hormone levels.CONCLUSIONS:Our results confirmed the high prevalence of hypovitaminosis D in patients undergoing kidney transplant. Therapeutic strategies such as moderate sunlight exposure and vitamin D supplementation should be seriously considered for this population.

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“…These seasonal cyclical VitD results suggest there may be poor compliance with sun avoidance behaviours despite repeated reminders to avoid sunlight, sunbathing and to use sun protection (hats, gloves, creams) [20]. This asymmetrical seasonality response to VitD repletion, with winter repletion associated with inadequate restoration of 25(OH)D, indicates that structured dose-adjustments are probably required to optimize the repletion regimen.…”

Section: Discussionmentioning

confidence: 99%

Impact of seasonality on the dynamics of native Vitamin D repletion in long-term renal transplant patients

et al. 2017

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Background: Renal transplant recipients (RTRs) are often Vitamin D (VitD) depleted as a result of both chronic kidney disease and mandated sun avoidance behaviours. Repleting VitD may be warranted, but how, and for how long, is unknown, as is the impact of seasonality on the success of repletion. We investigated the impact of seasonality on VitD status following VitD repletion in a large cohort of stable, long-term RTRs. Methods: Serum 25-hydroxyvitamin D [25(OH)D] concentrations and bone biochemistry parameters were analysed from 102 VitD repletion courses in 98 RTRs that had undergone VitD repletion. Repletion was delivered over 6 months with either 240 000 IU colecalciferol if pre-repletion serum VitD was between 20 and 50 nmol/L, or with 360 000 IU if VitD was <20 nmol/L. Twelve months post-repletion 25(OH)D and parathyroid hormone (PTH) were available for 75 patients. Results: At baseline, 25(OH)D was 20.1 ± 1.0 nmol/L, increasing to 65.4 ± 1.8 nmol/L following repletion (+7.55 nmol/L/month, P < 0.0001). Twelve months post-repletion and after no further VitD administration, 25(OH)D fell to 35.4 ± 1.8 nmol/L (14.2 ± 0.7 ng/mL; −2.50 nmol/L/month, P < 0.0001). PTH followed the opposite trend with baseline, repletion-end and post-repletion values being 144.2 ± 12.0, 109.6 ± 7.5 and 129.2 ± 11.4 ng/L, respectively. VitD repletion during the summer was associated with significantly higher at repletion-end 25(OH)D compared with any other time of year [summer 80.9 ± 4.0, autumn 64.1 ± 3.0 (P = 0.002), winter 48.9 ± 3.0 (P <0.001), spring 63.8 ± 2.5 nmol/L (P <0.001)]. There was no hypercalcaemia during repletion and renal transplant function remained stable without any evidence of allograft rejection. Conclusions: VitD repletion can safely and effectively be achieved in the majority of chronic stable RTRs using a 6-month bolus intermediate-dose schedule. Winter repletion is associated with an inadequate response in 25(OH)D; however, all patients experience a post-repletion fall towards deficiency in the absence of maintenance supplementation, irrespective of the season of repletion.

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Determinants of vitamin D status in long‐term renal transplant patients

Cited by 19 publications

References 30 publications

Mineral and bone disorder after kidney transplantation

Mineral and bone disorder after kidney transplantation

Hypovitaminosis D in patients undergoing kidney transplant: the importance of sunlight exposure

Impact of seasonality on the dynamics of native Vitamin D repletion in long-term renal transplant patients

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