Background/Aims: Vitamin D insufficiency and secondary hyperparathyroidism (SHPT) are associated with increased morbidity and mortality in chronic kidney disease (CKD) and are poorly addressed by current treatments. The present clinical studies evaluated extended-release (ER) calcifediol, a novel vitamin D prohormone repletion therapy designed to gradually correct low serum total 25-hydroxyvitamin D, improve SHPT control and minimize the induction of CYP24A1 and FGF23. Methods: Two identical multicenter, randomized, double-blind, placebo-controlled studies enrolled subjects from 89 US sites. A total of 429 subjects, balanced between studies, with stage 3 or 4 CKD, SHPT and vitamin D insufficiency were randomized 2:1 to receive oral ER calcifediol (30 or 60 µg) or placebo once daily at bedtime for 26 weeks. Most subjects (354 or 83%) completed dosing, and 298 (69%) entered a subsequent open-label extension study wherein ER calcifediol was administered without interruption for another 26 weeks. Results: ER calcifediol normalized serum total 25-hydroxyvitamin D concentrations (>30 ng/ml) in >95% of per-protocol subjects and reduced plasma intact parathyroid hormone (iPTH) by at least 10% in 72%. The proportion of subjects receiving ER calcifediol who achieved iPTH reductions of ≥30% increased progressively with treatment duration, reaching 22, 40 and 50% at 12, 26 and 52 weeks, respectively. iPTH lowering with ER calcifediol was independent of CKD stage and significantly greater than with placebo. ER calcifediol had inconsequential impact on serum calcium, phosphorus, FGF23 and adverse events. Conclusion: Oral ER calcifediol is safe and effective in treating SHPT and vitamin D insufficiency in CKD.

Background: Pruritus is a distressing hallmark of the uremic condition, affecting approximately 60% of hemodialysis patients. Abnormal endogenous opioid ligand activity at μ and κ-opioid receptors has been postulated as a mechanism in uremic pruritus. Nalbuphine is a μ-opioid antagonist and κ-opioid agonist. Methods: In this multicenter, randomized, double-blind, placebo-controlled trial, 373 hemodialysis patients with moderate or severe uremic pruritus were randomized in a 1: 1:1 ratio to nalbuphine extended-release tablets 120 mg (NAL 120), 60 mg (NAL 60), or placebo and treated for 8 weeks. Three hundred seventy-one were analyzed for efficacy. The primary endpoint was the change from baseline to treatment weeks 7 and 8 in itching intensity on a Numerical Rating Scale (NRS, 0 [no itching]; 10 [worst possible itching]) using an intent-to-treat approach. The aim was to evaluate the safety and antipruritic efficacy of NAL. Results: The mean duration of itching was 3.2 years. From a baseline NRS of 6.9 (1.5), the mean NRS declined by 3.5 (2.4) and by 2.8 (2.2) in NAL 120 mg and the placebo groups, respectively (p = 0.017). There was no evidence of tolerance. A trend for less sleep disruption due to itching (p = 0.062, NAL 120 vs. placebo) was also observed. There were no significant differences between NAL 60 vs. placebo. Serious adverse events occurred in 6.7, 12.7, and 15.4% in the NAL 120, NAL 60, and placebo groups respectively. Conclusions: In this largest-to-date randomized controlled trial in uremic pruritus, NAL 120 durably and significantly reduced the itching intensity among hemodialysis patients.

The purpose of this study was to examine proximal and distal tubular function in rats with nonoliguric, myohemoglobinuric acute renal failure (ARF). ARF was induced with glycerol (50%, 10 ml/kg of body wt, i.m.), and renal function was studied 24 hours after glycerol or saline (controls) injection. Glycerol injection caused a 50 to 90% depression in GFR and a significant rise in blood urea nitrogen concentration. Animals with ARF exhibited glycosuria with normal blood sugar levels and a striking depression in tubular glucose reabsorption per milliliter of GFR. The capacity to reabsorb (mEq/liter GFR) was intact at normal blood bicarbonate levels, but was markedly depressed when blood bicarbonate was raised. The tubular maximum for para-aminohippurate (PAH) secretion and the renal extraction fraction of PAH were strikingly depressed in rats with ARF. Distal acidification as assessed by the urine-to-blood gradient of PCO2 (UB PCO2) was normal both during maximal alkalinization of the urine with bicarbonate (urine pH, approximately 7.8) or during neural phosphate infusion (urine pH, approximately 7.0). Net acid excretion per milliliter GFR and minimal urine pH (less than 5.5) following 3 days of ammonium chloride ingestion was similar in control and ARF animals. Potassium excretion was intact in maximal urinary osmolality were significantly altered in animals with ARF. Cortical and outer medullary Na-K-ATPase specific activities were significantly depressed in ARF rats. This occurred as a consequence of enzyme loss and not secondary to alterations in enzyme kinetics of absolute tubular sodium reabsorption. Light and electron microscopy showed diffuse proximal tubular damage, whereas glomeruli and distal tubules were intact. These data demonstrate that glycerol injection produces a diffuse proximal tubular transport defect associated with histologic and enzymatic alterations.

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BACKGROUND: There is an epidemic of chronic kidney disease (CKD) and a high prevalence of anemia (47%) observed in CKD patients. Little is known about the cost in physician office resources of routine erythropoiesis-stimulating protein (ESP) administration to treat patients with nondialysis CKD.OBJECTIVES: The objectives of this research were (1) to explore the patterns of care in physician offices where nondialysis CKD patients receive routine ESP injections, (2) to examine differences in the monthly resources and related costs incurred by physician offices in treating patients receiving either weekly (QW) or monthly (QM) ESP regimens, and (3) to identify opportunities to minimize the burden of CKD treatment on physician offices.METHODS: An observational, cross-sectional time and motion assessment was performed in 10 community-based outpatient nephrology practices (5 QW and 5 QM practices); each practice had ≥40 patients on routine ESP therapy for nondialysis CKD. Three observers trained in health care research documented injection-related tasks and time associated with 91 ESP injection procedures (47 QW and 44 QM) from patients' arrival to and departure from the physician office, office personnel follow-up on billing and documentation, and injection-related staff time. Monthly injection times for QM were calculated by summing the time required to perform the tasks associated with administering a single injection of ESP to subjects, as documented by observers. Total monthly per-patient medical practice costs for providing QM ESP injections were calculated, including labor costs (calculated by applying average wage rates of practice staff to time observed for the specific activities performed) and supply costs (based on average list prices found in medical supply catalogs). Monthly injection times and costs for the QW regimen were calculated by summing the same list of activities as for the QM regimen and multiplying by 4.3 (4.3 weeks per month). Nephrology practice personnel completed a questionnaire summarizing practice characteristics and estimated the time required for some of the injection-related activities. The time and cost associated with each task were analyzed using descriptive and comparative statistics (i.e., Fisher's exact test and t test). RESULTS: On average, patients spent 21 minutes in the clinic for a routine injection visit (QW: 17 minutes, QM: 25 minutes; P = 0.053), during which 11 minutes (52%) were spent interacting with clinic staff (QW: 8.9 minutes, QM: 13.4 minutes; P = 0.005). In the time spent interacting with staff, 3 minutes (QW: 2.9 minutes, QM: 3.6 minutes; P = 0.065) were for dose administration and 8 minutes (QW: 5.3 minutes, QM: 9.8 minutes; P = 0.011) were for staff providing various services to the patients, including registering patients on arrival, examining patients (vital signs, weight, blood work), consulting with patients, and scheduling patients' next visits. Each month, clinic staff spent a total visit average of 38 minutes providing anemia-related treatment for each...