Faculty Bibliography

Each year approximately 13,000 Veterans transition to maintenance dialysis, mostly in the traditional form of thrice-weekly hemodialysis from the start. Among >6000 dialysis units nationwide, there are currently approximately 70 Veterans Affairs (VA) dialysis centers. Given this number of VA dialysis centers and their limited capacity, only 10% of all incident dialysis Veterans initiate treatment in a VA center. Evidence suggests that, among Veterans, the receipt of care within the VA system is associated with favorable outcomes, potentially because of the enhanced access to healthcare resources. Data from the United States Renal Data System Special Study Center "Transition-of-Care-in-CKD" suggest that Veterans who receive dialysis in a VA unit exhibit greater survival compared with the non-VA centers. Substantial financial expenditures arise from the high volume of outsourced care and higher dialysis reimbursement paid by the VA than by Medicare to outsourced providers. Given the exceedingly high mortality and abrupt decline in residual kidney function (RKF) in the first dialysis year, it is possible that incremental transition to dialysis through an initial twice-weekly hemodialysis regimen might preserve RKF, prolong vascular access longevity, improve patients' quality of life, and be a more patient-centered approach, more consistent with "personalized" dialysis. Broad implementation of incremental dialysis might also result in more Veterans receiving care within a VA dialysis unit. Controlled trials are needed to examine the safety and efficacy of incremental hemodialysis in Veterans and other populations; the administrative and health care as well as provider structure within the VA system would facilitate the performance of such trials.

IN BRIEF Dietary guidelines for patients with diabetes extend beyond glycemic management to include recommendations for mitigating chronic disease risk. This review summarizes the literature suggesting that excess dietary phosphorus intake may increase the risk of skeletal and cardiovascular disease in patients who are in the early stages of chronic kidney disease (CKD) despite having normal serum phosphorus concentrations. It explores strategies for limiting dietary phosphorus, emphasizing that food additives, as a major source of highly bioavailable dietary phosphorus, may be a suitable target. Although the evidence for restricting phosphorus-based food additives in early CKD is limited, diabetes clinicians should monitor ongoing research aimed at assessing its efficacy.

PURPOSE: Kidney stone prevention relies on the 24-hour urine collection to diagnose metabolic abnormalities and direct dietary and pharmacologic therapy. While its use is guideline-supported for high risk and interested patients, evidence that the test can accurately predict recurrence or treatment response is limited. We sought to critically reassess the role of the 24-hour urine collection in stone prevention. MATERIALS AND METHODS: In addition to a MEDLINE(R) search to identify controlled studies of dietary and pharmacologic interventions, evidence supporting the AUA and EAU guidelines for metabolic stone prevention were evaluated. Additionally, placebo-arms of these studies were examined to assess the stone clinic effect: the impact of regular office visits without specific treatment on stone recurrence. RESULTS: The 24-hour urine test has several limitations including the complexity of interpretation, need for repeat collections, inability to predict stone recurrence with individual parameters and supersaturation values, unclear rationale of laboratory cutoff values, and difficulty with determining collection adequacy. Only one prospective trial has compared selective dietary recommendations based on 24-hour urine collection results versus general dietary instructions. While the trial supported the intervention arm, significant limitations to the study were found. Placebo arms of intervention trials have noted a 0-61% decrease in stone recurrence rate and a remission rate during the study of 20-86%. CONCLUSIONS: Whether all recurrent stone formers benefit from 24-hour urine collection has not been established. Additional comparative effectiveness trials are needed to determine which stone former benefits from selective therapy, as guided by the 24-hour urine collection.

BACKGROUND: Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. DESIGN: A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. RESULTS: Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. CONCLUSIONS: This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified.