Vitamin D as a risk factor for patient survival after kidney transplantation: A prospective observational cohort study.

BACKGROUND: Short-term survival after kidney transplantation is excellent, but long-term survival remains low and is equivalent to non-end-stage renal disease patients with many invasive malignancies. The aim of the study was to explore vitamin D status in the early phase after transplantation as a prognostic marker for long-term graft and patient survival. METHODS: All first-time kidney transplant recipients between October 2007 and October 2012 in Norway were included. Vitamin D was measured 10 weeks post-transplant. Information on graft failure and death was obtained from the Norwegian Renal Registry. RESULTS: Seven hundred and sixty-two first-time kidney transplant recipients were included, with a median age of 57 years and a median follow-up of 82 months. In the follow-up period, there were 172 graft failures (23%) and 118 deaths (15%). Eighty-six percent of the transplant recipients with sufficient vitamin D levels were alive with a well-functioning graft after 5 years using Kaplan-Meier survival estimates, compared with 79% and 76% of the patients with vitamin D deficiency and insufficiency, respectively (P = 0.006). CONCLUSION: In a nation-wide cohort of 762 first-time kidney transplant recipients, long-term graft and patient survival were better in recipients with vitamin D sufficiency 10 weeks post-transplant compared with those with vitamin D deficiency and insufficiency.

Parathyroid hormone and clinical outcome in kidney transplant patients with optimal transplant function.

BACKGROUND: The aim of the study was to investigate whether serum levels of intact parathyroid hormone (iPTH) are associated with an increased risk of cardiovascular events, graft loss, or mortality in kidney transplant patients with optimal transplant function. METHODS: From the Norwegian Renal Registry, we identified 522 patients who received a first kidney transplant from 2001 to 2008 with optimal transplant function defined as an estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m2, more than one yr after transplantation. Cox's proportional hazard models were used to assess the association between iPTH measured 10 wk after transplantation and the composite endpoint. The estimates were adjusted for age, gender, serum calcium, serum phosphate, diabetes mellitus, cardiovascular disease, and time on dialysis prior to transplantation. RESULTS: Median follow-up time was 3.9 yr (interquartile range, IQR: 2.0-6.0 yr). Patients in the third iPTH quartile (9.3-14.4 pM) had the lowest risk for reaching the composite endpoint. Patients in the fourth iPTH quartile (>14.4 pM) had an increased risk compared to those in the third quartile (HR: 2.60, 95% CI: 1.10-6.16, p=0.03). CONCLUSION: In patients with optimal transplant function, iPTH levels are associated with a clinical outcome consisting of cardiovascular events, graft loss, and all-cause mortality.

Glycated albumin and post-transplant diabetes mellitus in kidney transplant recipients.

BACKGROUND: Post-transplant diabetes mellitus is one of the most important cardiovascular risk factors after solid organ transplantation. Factors other than hyperglycaemia found in patients post-transplant, affect the level of haemoglobin A1c (HbA1c), and new markers of hyperglycaemia are needed. Our aim was to establish a 95% reference interval for glycated albumin in kidney transplant recipients, and to compare glycated albumin concentrations to the diagnostic criteria for diabetes mellitus post-transplant using oral glucose tolerance test and HbA1c. METHODS: A total of 341 non-diabetic kidney transplant recipients aged ≥18 years who underwent an oral glucose tolerance test at 8 weeks and 1 year after transplantation were included. Glycated albumin was determined by liquid chromatography coupled with tandem mass spectrometry. RESULTS: The 95% reference interval for glycated albumin was 8.2 (90% CI: 7.2-8.5) to 12.8% (90% CI: 12.2-13.5) which is not significantly different from our laboratory's 95% reference interval for persons without diabetes. At both 8 weeks and 1 year after transplantation, 35 patients (10.3%) fulfilled one, two or all three diagnostic criteria for diabetes mellitus. One year after transplantation, eight additional patients had glycated albumin concentration >12.8%. CONCLUSION: Our findings are in accordance with the notion that kidney transplant recipients form glycation end products like normal controls as estimated by glycated albumin and HbA1c. Further studies should address glycated albumin as a supplemental tool for the diagnosis of post-transplant diabetes mellitus in kidney transplant recipients.

Fibroblast growth factor 23 and parathyroid hormone after treatment with active vitamin D and sevelamer carbonate in patients with chronic kidney disease stage 3b, a randomized crossover trial.

BACKGROUND: Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that is secreted from bone and serum level increases as renal function declines. Higher levels of FGF23 are associated with increased mortality in hemodialysis-patients and in patients with chronic kidney disease (CKD) stage 2-4. The use of active vitamin D and phosphate binders as recommended in international guidelines, may affect the level of FGF23 and thereby clinical outcome. We investigated the effects of a phosphate binder and active vitamin D on the serum levels of intact FGF23 (iFGF23) and intact parathyroid hormone (iPTH) in patients with CKD stage 3b (glomerular filtration rate (GFR) 30-44 ml/min/1.73 m(2)). METHODS: Seven women and 14 men were included, mean age 65.6 ± 12.2 years. They were randomized in a 1:1 ratio to receive one of two treatment sequences. Group-1 (the alphacalcidol-sevelamer carbonate group): alphacalcidol 0.25 µg once daily for two weeks followed by sevelamer carbonate 800 mg TID with meals for two weeks after a two-week washout period. Group-2 (the sevelamer carbonate-alphacalcidol group): vice versa. Nineteen patients completed the study. The 25-hydroxyvitamin D level at baseline was 97.6 ± 25.0 nmol/l. RESULTS: There were no treatment effects on the iFGF23 and iPTH levels overall. In group-1 the iFGF23 level was higher after treatment with alphacalcidol compared with sevelamer carbonate (mean 105.8 ± 41.6 vs. 79.1 ± 36.5 pg/ml, p = 0.047 (CI: 0.4-52.9), and the iPTH level was lower (median: 26.5, range: 14.6-55.2 vs. median 36.1, range 13.4-106.9 pg/ml, p = 0.011). In group-2 the iFGF23 level increased non-significantly after treatment with sevelamer carbonate and throughout the washout period. CONCLUSIONS: In this crossover trial with alphacalcidol and sevelamer carbonate in patients with CKD stage 3b, the levels of iFGF23 were not significantly different after the two treatments. However, in the group of patients initiating therapy with sevelamer carbonate the iFGF23 levels seemed to increase while this response was mitigated in the group of patients given alphacalcidol followed by sevelamer carbonate. This may have therapeutic implications on choice of first line therapy. The number of patients is small and this conclusion is in part based on subgroup analysis. It is therefore important that these results are confirmed in larger studies. TRIAL REGISTRATION NUMBER: European Clinical Trial Database (EudraCT) 2010-020415-36 and Clinical Trials.gov NCT01231438.

Intact parathyroid hormone levels in renal transplant patients with normal transplant function.

INTRODUCTION: Chronic kidney disease mineral and bone disorder (CKD-MBD) is common in patients who have undergone kidney transplantation. There is limited information on the extent to which patients with normal renal function after transplantation have persistent disturbances in their mineral metabolism. AIM: The aim of the study is to investigate the prevalence of elevated intact parathyroid hormone (iPTH) levels at least one yr after transplantation in patients living with a first renal transplant with normal transplant function. METHODS: A retrospective, observational study of 607 patients was collected from the Norwegian Renal Registry. Of these, iPTH was recorded for 360 patients. RESULTS: One hundred and eighty-eight patients (52%) had elevated iPTH levels. Twenty-six patients (7%) had iPTH levels >2.5 times the upper limit of normal (ULN). Patients with a pre-emptive transplant were significantly younger than the patients who had received treatment with dialysis (p < 0.0001). The prevalence of iPTH > ULN was significantly higher in patients with a pre-emptive transplant (p = 0.037). CONCLUSIONS: In post-transplant patients with normal transplant function, our data indicate that more than 50% have elevated levels of iPTH more than one yr after transplantation. If elevated iPTH level is associated with mortality in this patient population, it may have major impact on clinical treatment guidelines.

Soluble Klotho and intact fibroblast growth factor 23 in long-term kidney transplant patients.

BACKGROUND: Controversies exist whether disturbances in mineral and bone disorder (MBD) normalise or persist after kidney transplantation. We assessed markers of MBD in patients with well-functioning kidney transplants to minimise confounding by reduced transplant function. METHODS: In this cross-sectional study, 40 patients aged ≥18 years who received a first kidney transplant more than 10 years ago were included. A well-functioning transplant was defined as an estimated glomerular filtration rate (eGFR) ≥45 ml/min per 1.73 m(2). RESULTS: Median time since transplantation was 18.3 years (inter quartile range (IQR) 12.2-26.2). Albumin-corrected serum calcium levels were above upper limit of normal in 15% of the transplanted patients, and serum phosphate levels below lower limit of normal in 31%. The median levels of intact parathyroid hormone (iPTH) and intact fibroblast growth factor 23 (iFGF23) were significantly higher than that in a group of healthy volunteers (11.3 pmol/l (IQR: 8.7-16.2) vs 4.4 pmol/l (IQR: 3.8-5.9), P<0.001 and 75.0 pg/ml (IQR: 53.3-108.0) vs 51.3 pg/ml (IQR: 36.3-67.6), P=0.004 respectively). There was a non-significant reduction in soluble Klotho (sKlotho) levels (605 pg/ml (IQR: 506-784) vs 692 pg/ml (IQR: 618-866)). When compared with a control group matched for eGFR, levels of iPTH were significantly higher (P<0.001), iFGF23 had a non-significant trend towards higher levels and sKlotho towards lower levels. CONCLUSIONS: In long-term kidney transplant patients with well-functioning kidney transplants, we found inappropriately high levels of iPTH and iFGF23 consistent with a state of persistent hyperparathyroidism. We speculate that the primary defect, FGF23 resistance, has evolved in the parathyroid gland before transplantation, and persists due to long half-life of the parathyroid cells.

[Thyrotoxic periodic paralysis--an unusual complication of hyperthyroidism]. / Tyreotoksisk periodisk paralyse--en uvanlig komplikasjon ved hypertyreose.

BACKGROUND: Thyrotoxic periodic paralysis (TPP) is a complication of hyperthyroidism. MATERIALS AND METHODS: We describe two patients with TPP. RESULTS: A 26-year-old man from Vietnam had weight loss, tachycardia, palpitations and heat intolerance for five months. Episodic leg and arm weakness developed three months after debut of symptoms. The second patient, a 23-year old woman from the Philippines, had had episodic leg weakness in the evenings after dinner for three weeks. Her attacks resolved spontaneously overnight. Physical examination of both patients revealed tachycardia and symmetrical proximal weakness involving both arms and legs. ECG and electrolyte analysis indicated a severe hypokalaemia; thyroid function tests showed hyperthyroidism. Both patients were diagnosed as having Graves' thyrotoxicosis and TPP. They were initially treated with propranolol and subsequently with carbimazole. The first patient had recurrence of thyrotoxicosis and paralysis after 16 months, whereas the second patient has remained symptom-free. INTERPRETATION: TPP is most common in Asian males, very few cases are reported in females. In Western countries TPP is rare, but with increasing immigration, TPP is likely to occur more frequently.