Acute Treatment Effects on GFR in Randomized Clinical Trials of Kidney Disease Progression.

Background: Acute changes in GFR can occur after initiation of interventions targeting progression of CKD. These acute changes complicate the interpretation of long-term treatment effects.

Methods: To assess the magnitude and consistency of acute effects in randomized clinical trials and explore factors that might affect them, we performed a meta-analysis of 53 randomized clinical trials for CKD progression, enrolling 56,413 participants with at least one estimated GFR measurement by 6 months after randomization.

Biased estimation with shared parameter models in the presence of competing dropout mechanisms.

Recently, Thomadakis et al. quantified potential sources of bias that can occur when shared parameter (SP) models are used to jointly model longitudinal trends of a biomarker over time (e.g.

Performance of GFR Slope as a Surrogate End Point for Kidney Disease Progression in Clinical Trials: A Statistical Simulation.

Background: Randomized trials of CKD treatments traditionally use clinical events late in CKD progression as end points. This requires costly studies with large sample sizes and long follow-up. Surrogate end points like GFR slope may speed up the evaluation of new therapies by enabling smaller studies with shorter follow-up.

GFR Slope as a Surrogate End Point for Kidney Disease Progression in Clinical Trials: A Meta-Analysis of Treatment Effects of Randomized Controlled Trials.

Background: Surrogate end points are needed to assess whether treatments are effective in the early stages of CKD. GFR decline leads to kidney failure, but regulators have not approved using differences in the change in GFR from the beginning to the end of a randomized, controlled trial as an end point in CKD because it is not clear whether small changes in the GFR slope will translate to clinical benefits.

Methods: To assess the use of GFR slope as a surrogate end point for CKD progression, we performed a meta-analysis of 47 RCTs that tested 12 interventions in 60,620 subjects.

Calculating Standard Kt/V during Hemodialysis Based on Urea Mass Removed.

Background/aims: We derived a novel equation for calculating weekly urea standard Kt/V (stdKt/V) during hemodialysis (HD) based on urea mass removed, comparable to the approach during peritoneal dialysis.

Methods: Theoretical consideration of urea mass balance during HD led to the following equation for stdKt/V, namely, stdKt/V = N × (URR + UFV/V), where N is the number of treatments per week, URR is urea reduction ratio per treatment, UFV is ultrafiltration volume per treatment, and V is postdialysis urea distribution volume. URR required corrections for postdialysis rebound and intradialytic urea generation.

Survival of propensity matched incident peritoneal and hemodialysis patients in a United States health care system.

We sought to compare survival among incident peritoneal dialysis (PD) patients to matched hemodialysis (HD) patients who received pre-dialysis care, including permanent dialysis access placement. Patients starting PD were propensity matched to those starting HD. HD patients who used a central venous catheter during the first 90 days of dialysis were excluded.

PSA enzymatic activity: a new biomarker for assessing prostate cancer aggressiveness.

Background: With the advent of widespread prostate-specific antigen (PSA) testing in recent decades, prostate cancer (PCa) has emerged as the most frequently diagnosed non-skin cancer among men in the U.S. and Europe.

What is the true number needed to screen and treat to save a life with prostate-specific antigen testing?

Purpose: The European Randomized Study of Screening for Prostate Cancer (ERSPC) reported a 20% mortality reduction with prostate-specific antigen (PSA) screening. However, they estimated a number needed to screen (NNS) of 1,410 and a number needed to treat (NNT) of 48 to prevent one prostate cancer death at 9 years. Although NNS and NNT are useful statistics to assess the benefits and harms of an intervention, in a survival study setting such as the ERSPC, NNS and NNT are time specific, and reporting values at one time point may lead to misinterpretation of results.

Assessing creatinine clearance from modification of diet in renal disease study equations in the ADEMEX cohort: limitations and potential applications.

Background And Objectives: Twenty-four-hour urine and dialysate collections provide accepted means to assess adequacy in peritoneal dialysis (PD). Recent publications suggest that creatinine clearance (CrCl) estimated from the Modification of Diet in Renal Disease (MDRD) equations (eCrCl) accurately approximates measured CrCl (mCrCl) derived from 24-hour collections of urine and dialysate and might serve as an alternative means to assess small-solute clearance and adequacy in PD.

Design, Setting, Participants, & Measurements: Post hoc analysis of data from patients enrolled in ADEMEX was used to assess agreement between mCrCl and eCrCl derived by four- and six-variable MDRD equations (4V-MDRDE and 6V-MDRDE, respectively).

Effects of radiotherapy with or without chemotherapy on tongue strength and swallowing in patients with oral cancer.

Background: Oral tongue strength and swallowing ability are reduced in patients treated with chemoradiotherapy for oral and oropharyngeal cancer.

Methods: Patients with oral or oropharyngeal cancer treated with high-dose chemoradiotherapy underwent tongue strength, swallowing, and dietary assessments at pretreatment and 1, 3, 6, and 12 months posttreatment. Tongue strength was assessed using the Iowa Oral Performance Instrument (IOPI).

The reverse epidemiology of plasma total homocysteine as a mortality risk factor is related to the impact of wasting and inflammation.

Background: The reason(s) for the apparently paradoxical 'reverse' association in end-stage renal disease (ESRD) patients in whom a low, rather than a high, total plasma total homocysteine (tHcy) level is an indicator of poor outcome remains unclear. The aim of this study was to examine whether the inverse association maintains, mitigates or reverses after comprehensive multivariate adjustment for the presence of wasting and inflammation as well as other potential confounders.

Methods: We studied 317 ESRD patients starting dialysis therapy.

Modeling of icodextrin in PD Adequest 2.0.

Objective: To validate the use of a modified three-pore model for predicting fluid transport during long dwell exchanges that use a 7.5% icodextrin solution.

Design: A nonrandomized, single group, repeated measures study.

Estrogen and progesterone levels in nipple aspirate fluid of healthy premenopausal women: relationship to steroid precursors and response proteins.

Background: Concentrations of estrogen and progesterone within the breast could provide a better reflection of breast cancer risk than levels in the circulation. We developed highly sensitive immunoassays for multiple steroid hormones and proteins in the nipple aspirate fluid (NAF), which can be obtained noninvasively with a simple suction device. Previous studies showed that NAF hormone levels are strongly correlated between breasts and within a single breast over time and are predictably related to hormone replacement therapy or use of oral contraceptives.

Shared parameter models for the joint analysis of longitudinal data and event times.

Longitudinal studies often gather joint information on time to some event (survival analysis, time to dropout) and serial outcome measures (repeated measures, growth curves). Depending on the purpose of the study, one may wish to estimate and compare serial trends over time while accounting for possibly non-ignorable dropout or one may wish to investigate any associations that may exist between the event time of interest and various longitudinal trends. In this paper, we consider a class of random-effects models known as shared parameter models that are particularly useful for jointly analysing such data; namely repeated measurements and event time data.

The differential impact of risk factors on mortality in hemodialysis and peritoneal dialysis.

Background: While the survival ramifications of dialysis modality selection are still debated, it seems reasonable to postulate that outcome comparisons are not the same for all patients at all times. Trends in available data indicate the relative risk of death with hemodialysis (HD) compared to peritoneal dialysis (PD) varies by time on dialysis and the presence of various risk factors. This study was undertaken to identify key patient characteristics for which the risk of death differs by dialysis modality.

Hemoglobin levels and erythropoietin doses in hemodialysis and peritoneal dialysis patients in the United States.

Erythropoietic agents, a cornerstone of management, are a major component of the cost of renal replacement therapy. The objectives of this study were to compare (on a month-by-month basis) U.S.

Eating ability in head and neck cancer patients after treatment with chemoradiation: a 12-month follow-up study accounting for dropout.

Background: Head and neck cancer patients treated with chemoradiation have difficulty eating a normal diet. This study was designed to characterize eating ability over 12 months after chemoradiation treatment. Analyses take patient dropout into account.

Body size and outcomes on peritoneal dialysis in the United States.

Background: Being overweight is often cited as a relative contraindication to peritoneal dialysis. Our primary objective was to determine whether actual mortality rates support this opinion.

Methods: Retrospective cohort study of United States Medicare patients initiating dialysis between 1995 and 2000 (N = 418,021; 11% peritoneal dialysis).

The effect of technique failure on outcome in black patients on continuous ambulatory peritoneal dialysis.

Background: We previously reported that, while black patients have a better patient survival than white patients on peritoneal dialysis (PD), they also have a significantly higher technique failure rate (39% vs 8%, p < 0.0001). The purpose of this study was to determine the effect of technique failure/transfer to hemodialysis (HD) on patient survival in black PD patients.