Early initiation of dialysis fails to prolong survival in patients with end-stage renal failure.
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Humans↗
Biomedical subjects
Jamie P Traynor
Publications and source records attributed to Jamie P Traynor.
Predicting 30-minute postdialysis blood urea concentrations using the stop dialysate flow method.
The stop dialysate flow (SDF) method has been the recommended method of postdialysis urea sampling by the Scottish Renal Association since November 1998. However, this method does not lend itself to calculation of Kt/V using currently favored formulas, which require either a 30-minute postdialysis sample or a 20-second "slow flow" sample. We, therefore, derived a formula that uses a 5-minute postdialysis urea sample using the SDF method to estimate the urea concentration at 30 minutes. Blood samples were obtained from 70 hemodialysis patients immediately before dialysis and at 0, 5, and 30 minutes postdialysis. Half of the patients from each unit were randomly selected to form the linear regression equation: Estimated 30-minute urea concentration = 1.06 x (5-minute urea concentration) + 0.22. This equation was validated using the data from the remaining 35 patients. This showed a very close correlation between measured and estimated urea concentration at 30 minutes (R2 = 0.97), and a Bland-Altman plot confirmed this close relationship. The sensitivity, specificity, positive, and negative predictive values of this equation were high when used to estimate 30-minute urea reduction ratio (URR) greater than 65% (100%, 85.7%, 97%, and 100%, respectively) and 30-minute Kt/V greater than 1. 2 (96.7%, 100%, 100%, and 80%, respectively). The coupling of the SDF method with the above formula combines the advantages of simple and reproducible postdialysis blood sampling with an accurate estimation of the 30-minute postdialysis blood urea concentration, URR, and Kt/V. This method should be a useful tool for comparative audit of hemodialysis adequacy.
Adult↗
Derived equations are not precise enough to predict the adequacy of creatinine clearance in peritoneal dialysis patients.
BACKGROUND: Most renal units assess dialysis adequacy in peritoneal dialysis (PD) patients by formal 24-hour collections of urine and effluent dialysate. We sought a reliable method of predicting dialysis adequacy that allows a decrease in the frequency of these formal and cumbersome measurements. METHODS: We created a formula for estimating total creatinine clearances, then assessed the clinical utility of this formula and other published formulae in predicting adequate and inadequate dialysis in PD patients. We collected data over a 6-month period in 2001 from 288 PD patients from 9 centers in Scotland. Four out of every 5 patients were selected at random to create a formula for estimating total creatinine clearance per week, and the fifth patient was used to form a validation group. We plotted creatinine excretion against age, and the resultant linear regression equation was transformed to produce a formula for predicting total creatinine clearance per week, based on patient sex, weight, and serum creatinine. We used the data from the validation subgroup to calculate predictive values for our derived formula and data from all of the patients to calculate predictive values for the Cockcroft and Gault, Jones, and Modification of Diet in Renal Disease Study formulae. RESULTS: Neither our derived formula nor the three published formulae were sufficiently powerful to predict accurately either adequate or inadequate PD clearance. Receiver operator characteristic curves showed that no significant improvement in these predictive values could be achieved by altering either the sensitivity or the specificity. CONCLUSION: Prediction formulae are not accurate enough to detect underdialysis in PD patients.
Adolescent↗
Early initiation of dialysis fails to prolong survival in patients with end-stage renal failure.
There is a trend to start dialysis earlier in patients with chronic renal failure. Studies that suggest improved survival from earlier initiation of dialysis are flawed in that they have measured survival from start of dialysis rather than from a time point before dialysis, when patients have the same renal function. This flaw is termed lead-time bias. Using the electronic patient record at the renal unit of Glasgow Royal Infirmary, all patients were identified who had received dialysis for chronic renal failure and who had sufficient data to calculate the time point at which they reached an estimated creatinine clearance (eC(Cr)) of 20 ml/min (n = 275). This date was used to time survival. The patients were divided into early and late start groups by the median eC(Cr) for all patients at initiation of dialysis, which was 8.3 ml/min. There was no significant benefit in patient survival from earlier initiation of dialysis. A Cox proportional hazards model demonstrated a significant inverse relationship between eC(Cr) at start of dialysis and survival (hazard ratio, 1.1; P = 0.02), i.e., patients who started dialysis with a lower eC(Cr) tended to survive longer. This relationship retained significance when gender, age, weight, presence of diabetes, mode of first dialysis, initial dialysis access, hemoglobin, serum albumin, blood leukocyte count, Wright/Khan index, and eC(Cr) at the start of dialysis were taken into account. This study fails to support a policy of earlier initiation of dialysis for patients with end-stage renal failure.
Female↗