Shorter dialysis times are associated with higher mortality among incident hemodialysis patients.

There is an association between hemodialysis session length and mortality independent of the effects of session duration on urea clearance. However, previous studies did not consider changes in session length over time nor did they control for the influence of time-dependent confounding. Using data from a national cohort of 8552 incident patients on thrice-weekly, in-center hemodialysis, we applied marginal structural analysis to determine the association between session length and mortality.

Prescribing and monitoring hemodialysis dose.

Small patients require higher Kt/V, the ratio of dialysis dose (the product of small-molecule clearance (K) and dialysis session length (t) to body water volume (V), than large patients. The errors implicit in Kt/V for judging hemodialysis dose are reviewed; methods for prescribing hemodialysis based on new technology are discussed; and thoughts about future development are suggested.

The epidemiology of systolic blood pressure and death risk in hemodialysis patients.

Background: This study compares the associations of predialysis systolic blood pressure (SBP) with mortality risk in both incident and prevalent hemodialysis (HD) cohorts by using both conventional and time-varying Cox analyses, thus addressing limitations of prior studies.

Methods: A total of 56,338 incident patients starting HD therapy during 1997 to 2001 and 69,590 prevalent HD patients on January 1, 2002, were grouped into the following categories: (1) SBP less than 120 mm Hg, (2) 120 < or = SBP < 140 mm Hg, (3) 140 < or = SBP < 160 mm Hg, (4) 160 < or = SBP < 180 mm Hg, (5) 180 < or = SBP < 200 mm Hg, and (6) SBP of 200 mm Hg or greater. Conventional and time-varying models evaluated 1-year and 3-year (incident patients only) survival.

The online measurement of hemodialysis dose (Kt): clinical outcome as a function of body surface area.

Background: Recent advances enable the direct measurement of small molecule clearance, Kecn, during each dialysis. Average Kecn and treatment length, t, are multiplied giving total clearance, Kt. The body surface area (BSA) is a fixed transformation of height and weight and is a well recognized measure of body size.

Intradialytic blood volume monitoring in ambulatory hemodialysis patients: a randomized trial.

Complications related to inadequate volume management are common during hemodialysis. This trial tested the hypothesis that availability of an intradialytic blood volume monitoring (IBVM) device improves fluid removal, reducing morbidity. A six-center, randomized trial with 6 mo of intervention comparing IBVM using Crit-Line versus conventional clinical monitoring was conducted.

Measurement of dialyzer clearance, dialysis time, and body size: death risk relationships among patients.

Background: Urea pharmacokinetic equation systems have contributed to better understanding of treatment dose among hemodialysis patients. The methods are indirect, however, and require the measurement of blood urea nitrogen (BUN) concentration before and after a dialysis session to estimate the total treatment dose that clinicians prescribe [urea clearance x dialysis time (Kt)] indexed to an estimate of body size [the volume of urea distribution in the body (V)] yielding the ratio, Kt/V. New technology permits direct on-line measurement of average small molecule clearance (Kecn) during each dialysis treatment that can be multiplied by time (t) to give a direct measurement of total treatment dose (Kt).

Vector length as a proxy for the adequacy of ultrafiltration in hemodialysis.

Background: Evaluation of dialysis adequacy has focused on parameters of solute (principally urea) clearance. Relatively little attention has been paid to the adequacy of ultrafiltration. At a given phase angle, the bioimpedance vector length reflects the degree of tissue hydration, as the vector lengthens with ultrafiltration.

Reprocessing dialysers for multiple uses: recent analysis of death risks for patients.

Background: Reprocessing dialysers is a common cost-saving practice in the USA. It began when patients were treated with bio-incompatible cellulosic membranes that were associated with medical complications, but has continued for economic reasons despite the current use of more biocompatible non-cellulosic membranes. A dialysis services and product provider using primarily its own non-cellulosic membranes recently embarked on a staged programme to stop reprocessing dialysers.

Mineral metabolism, mortality, and morbidity in maintenance hemodialysis.

Mortality rates in ESRD are unacceptably high. Disorders of mineral metabolism (hyperphosphatemia, hypercalcemia, and secondary hyperparathyroidism) are potentially modifiable. For determining associations among disorders of mineral metabolism, mortality, and morbidity in hemodialysis patients, data on 40,538 hemodialysis patients with at least one determination of serum phosphorus and calcium during the last 3 mo of 1997 were analyzed.

Interactions between dialysis-related volume exposures, nutritional surrogates and mortality among ESRD patients.

Background: Interdialytic weight gain is used as a surrogate for volume expansion in haemodialysis patients and as an indicator of non-compliance. Increased weight gain is associated with both a greater mortality risk and better nutrition indices. This analysis characterizes the association between dialysis-related volume expansion and mortality in the context of its interaction with nutritional surrogates.

Medical outcomes study short form-36: a consistent and powerful predictor of morbidity and mortality in dialysis patients.

Background: One of the guidelines released by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) recommends that patients with glomerular filtration rate (GFR) less than 60 mL/min/1.73 m2 undergo regular assessment of functioning and well-being (FWB) to establish baselines, monitor changes in FWB over time, and assess the effect of interventions on FWB. Although this recommendation stresses the importance of assessing and monitoring physical and mental health functioning, the Medical Outcomes Study Short Form-36 (MOS SF-36) might also be useful for predicting crucial longer-term patient outcomes.

White blood cells as a novel mortality predictor in haemodialysis patients.

Background: Many conventional cardiovascular risk factors in the general population are not as predictive in end-stage renal disease (ESRD). As absolute neutrophil count and total white blood cell (WBC) count are associated with adverse cardiovascular outcomes and all-cause mortality, this analysis was undertaken to explore the associations of WBC variables with mortality risk in ESRD.

Methods: Of a total study population of 44 114 ESRD patients receiving haemodialysis during 1998 at facilities operated by Fresenius Medical Care, North America, 25 661 patients who underwent differential white cell count and had complete follow-up were included.

Toward a continuous quality improvement paradigm for hemodialysis providers with preliminary suggestions for clinical practice monitoring and measurement.

Background: Consensus processes using the clinical literature as the primary source for information generally drive projects to draft clinical practice guidelines (CPGs). Most such literature citations describe special projects that are not part of an organized quality management initiative, and the publication/review/consensus process tends to be long. This project describes an initiative to develop and explore a flexible and dedicated data-driven paradigm for deciding new CPGs that could be rapidly responsive to changing medical knowledge and practice.

Body size, dialysis dose and death risk relationships among hemodialysis patients.

Background: The normalized treatment ratio, Kt/V derived from urea kinetic models (UKM), is a commonly used measure of dialysis dose. This measure assumes that smaller patients with low volume of urea distribution (V) require proportionately less total treatment (Kt) than larger patients. The conclusion has been questioned because the UKM use assumptions that could make them invalid for accurately predicting a clinical outcome like survival.

National profile of practice patterns for hemodialysis vascular access in the United States.

The Centers for Medicare & Medicaid Service's (CMS), national End-Stage Renal Disease (ESRD) Clinical Performance Measures (CPM) Project is a data collection initiative to identify opportunities for improvement of care to adult, Medicare maintenance dialysis beneficiaries. This analysis of 1999 CPM data characterizes the profile of hemodialysis vascular access in the United States and identifies determinants of vascular access type 2 yr after the translation of vascular access clinical practice guideline statements into national CPMs. CPM data were collected during October to December 1999 and stratified by the 18 regional ESRD networks.

Association between pulse pressure and mortality in patients undergoing maintenance hemodialysis.

Context: Although increased blood pressure is associated with adverse outcomes in the general population, elevated blood pressure is associated with decreased mortality in patients with end-stage renal disease undergoing maintenance hemodialysis. Recent investigations in the general population have demonstrated the predictive utility of pulse pressure (systolic minus diastolic blood pressure), a measure reflecting the pulsatile nature of the cardiac cycle.

Objectives: To estimate the relationship between pulse pressure and mortality in patients undergoing maintenance hemodialysis and to test our hypothesis that an increasing pulse pressure would be associated with increased risk of death up to 1 year despite the inverse relationship between conventional blood pressure measures and mortality in patients with end-stage renal disease.