Dataset Information

A two-pool kinetic model predicts phosphate concentrations during and shortly following a conventional (three times weekly) hemodialysis session.

ABSTRACT:

Background

Previous studies have suggested that a conventional two-pool model cannot be used to predict intradialysis and early postdialysis phosphorus concentrations.

Methods

A conventional two-pool urea model was modified by increasing the distal compartment volume from two-thirds to three times the total body water and by the use of a dynamically variable intercompartmental phosphorus clearance during dialysis. The phosphate solver model parameters were derived from an examination of the results in the literature, and fine-tuned using a training set (F4) of 415 Hemodialysis (HEMO) Study patients studied during a dialysis session where phosphorus was measured at 4 months of follow-up. Validation was done in a group of 380 different HEMO Study patients plus 9 from the original F4 group, who were evaluated at 36 months of follow-up.

Results

The model predicted measured median early (1 h) intradialysis, end-dialysis and 30-min postdialysis serum phosphorus levels in the test and validation datasets with little apparent bias, including the highest and lowest deciles of predialysis serum phosphorus. The model tended to underestimate slightly intradialysis serum phosphorus when predialysis serum phosphorus was <3.0 mg/dL (0.97 mmol/L). There was a large scatter and standard deviation among patients, and whether aberrant values represent a patient-specific phenomenon is unclear.

Conclusions

A modified two-pool model using a slightly expanded distal compartment and a dynamically varying intercompartmental clearance, depending on the intradialysis phosphorus concentration, can be used to predict serum phosphorus level during and shortly after dialysis, in patients following a conventional three times per week dialysis prescription.

SUBMITTER: Daugirdas JT

PROVIDER: S-EPMC5837537 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature

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Publications

A two-pool kinetic model predicts phosphate concentrations during and shortly following a conventional (three times weekly) hemodialysis session.

Daugirdas John T JT

Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association 20180101 1

<h4>Background</h4>Previous studies have suggested that a conventional two-pool model cannot be used to predict intradialysis and early postdialysis phosphorus concentrations.<h4>Methods</h4>A conventional two-pool urea model was modified by increasing the distal compartment volume from two-thirds to three times the total body water and by the use of a dynamically variable intercompartmental phosphorus clearance during dialysis. The phosphate solver model parameters were derived from an examinat ...[more]

PMID: 27738228

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Project description:BackgroundPhysical and emotional symptoms are prevalent in patients with kidney-dysfunction requiring dialysis (KDRD) and the rigors of thrice-weekly hemodialysis (HD) may contribute to deteriorated health-related quality of life. Less intensive HD schedules might be associated with lower symptom and/or emotional burden.MethodsThe TWOPLUS Pilot study was an individually-randomized trial conducted at 14 dialysis units, with the primary goal to assess feasibility and safety. Patients with incident KDRD and residual kidney function were assigned to incremental HD start (twice-weekly HD for 6 weeks followed by thrice-weekly HD) vs conventional HD (thrice-weekly HD). In exploratory analyses, we compared the two treatment groups with respect to three patient-reported outcomes measures. We analyzed the change from baseline in the score on Dialysis Symptom Index (DSI, range 0-150), Generalized Anxiety Disorder-7 (GAD-7, range 0-21), and Patient Health Questionnaire-9 (PHQ-9, range 0-27) at 6 (n = 20 in each treatment group) and 12 weeks (n = 21); with lower scores denoting lower symptom burden. Analyses were adjusted for age, race, gender, baseline urine volume, diabetes mellitus, and malignancy. Participants' views on the intervention were sought using a Patient Feedback Questionnaire (n = 14 in incremental and n = 15 in conventional group).ResultsThe change from baseline to week 6 in estimated mean score (standard error; P value) in the incremental and conventional group was - 9.7 (4.8; P = 0.05) and - 13.8 (5.0; P = 0.009) for DSI; - 1.9 (1.0; P = 0.07) and - 1.5 (1.4; P = 0.31) for GAD-7; and - 2.5 (1.1; P = 0.03) and - 3.5 (1.5; P = 0.02) for PHQ-9, respectively. Corresponding changes from week 6 to week 12 were - 3.1 (3.2; P = 0.34) and - 2.4 (5.5; P = 0.67) in DSI score; 0.5 (0.6; P = 0.46) and 0.1 (0.6; P = 0.87) in GAD-7 score; and - 0.3 (0.6; P = 0.70) and - 0.5 (0.6; P = 0.47) in PHQ-9 score, respectively. Majority of respondents felt their healthcare was not jeopardized and expressed their motivation for study participation was to help advance the care of patients with KDRD.ConclusionsThis study suggests a possible mitigating effect of twice-weekly HD start on symptoms of anxiety and depression at transition from pre-dialysis to KDRD. Larger clinical trials are required to rigorously test clinically-matched incrementally-prescribed HD across diverse organizations and patient populations.Trial registrationRegistered at ClinicalTrials.gov with study identifier NCT03740048, registration date 14/11/2018.

Project description:In this randomized clinical trial, we aimed to determine whether increasing the frequency of in-center hemodialysis would result in beneficial changes in left ventricular mass, self-reported physical health, and other intermediate outcomes among patients undergoing maintenance hemodialysis.Patients were randomly assigned to undergo hemodialysis six times per week (frequent hemodialysis, 125 patients) or three times per week (conventional hemodialysis, 120 patients) for 12 months. The two coprimary composite outcomes were death or change (from baseline to 12 months) in left ventricular mass, as assessed by cardiac magnetic resonance imaging, and death or change in the physical-health composite score of the RAND 36-item health survey. Secondary outcomes included cognitive performance; self-reported depression; laboratory markers of nutrition, mineral metabolism, and anemia; blood pressure; and rates of hospitalization and of interventions related to vascular access.Patients in the frequent-hemodialysis group averaged 5.2 sessions per week; the weekly standard Kt/V(urea) (the product of the urea clearance and the duration of the dialysis session normalized to the volume of distribution of urea) was significantly higher in the frequent-hemodialysis group than in the conventional-hemodialysis group (3.54±0.56 vs. 2.49±0.27). Frequent hemodialysis was associated with significant benefits with respect to both coprimary composite outcomes (hazard ratio for death or increase in left ventricular mass, 0.61; 95% confidence interval [CI], 0.46 to 0.82; hazard ratio for death or a decrease in the physical-health composite score, 0.70; 95% CI, 0.53 to 0.92). Patients randomly assigned to frequent hemodialysis were more likely to undergo interventions related to vascular access than were patients assigned to conventional hemodialysis (hazard ratio, 1.71; 95% CI, 1.08 to 2.73). Frequent hemodialysis was associated with improved control of hypertension and hyperphosphatemia. There were no significant effects of frequent hemodialysis on cognitive performance, self-reported depression, serum albumin concentration, or use of erythropoiesis-stimulating agents.Frequent hemodialysis, as compared with conventional hemodialysis, was associated with favorable results with respect to the composite outcomes of death or change in left ventricular mass and death or change in a physical-health composite score but prompted more frequent interventions related to vascular access. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; ClinicalTrials.gov number, NCT00264758.).

Dataset Information

A two-pool kinetic model predicts phosphate concentrations during and shortly following a conventional (three times weekly) hemodialysis session.

Background

Methods

Results

Conclusions

Publications

A two-pool kinetic model predicts phosphate concentrations during and shortly following a conventional (three times weekly) hemodialysis session.

Similar Datasets

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