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Estimation of total creatinine clearance is unreliable in children on peritoneal dialysis
C Aufricht1, E Kitzmüller, M A Lothaller
1Kinderdialyse, Universtätskinderklinik Wien, Vienna, Austria.
Insights
Estimating creatinine clearance in children on peritoneal dialysis is unreliable. A simultaneous formula clearance can help identify inaccurate measurements in pediatric patients undergoing PD.
Area of Science:
- Pediatric Nephrology
- Renal Replacement Therapy
- Clinical Chemistry
Background:
- Peritoneal dialysis (PD) is a treatment for end-stage renal disease in children.
- Accurate assessment of renal function is crucial for managing PD patients.
- Creatinine clearance (CCr) is a common measure of kidney function.
Purpose of the Study:
- To evaluate the reliability of creatinine clearance measurements in pediatric patients receiving PD.
- To compare the reliability of direct CCr measurements with formula-based estimations.
Main Methods:
- A longitudinal, case-controlled study was conducted with 11 children (2-13 years) on PD.
- Creatinine clearance was measured by collecting 24-hour urine and dialysate.
- Schwartz formula clearance was calculated concurrently for comparison.
Main Results:
- Twenty-seven percent of direct CCr measurements were found to be unreliable.
- Reliability of CCr was significantly influenced by residual renal function.
- Formula clearance demonstrated lower variability and could detect unreliable CCr values with 93% sensitivity.
Conclusions:
- Direct estimation of total creatinine clearance is unreliable in pediatric PD patients.
- Formula-based creatinine clearance serves as a valuable tool for identifying unreliable CCr measurements in this population.
Objective:
To test the reliability of creatinine clearance in children on peritoneal dialysis (PD).
Design:
Longitudinal, case-controlled.
Setting:
Routine clinic visits at the pediatric dialysis unit of the Universitätskinderklinik of Vienna.
Patients:
Eleven children (2-13 years, 10-55 kg) with end-stage renal disease on PD.
Interventions:
Creatinine clearance (CCr) was determined by measuring creatinine excretion (ECr) over 24 hours in both dialysate and urine. Each child had three to five separate measurements of their CCr. At the same time we also calculated the Schwartz formula clearance from the patient's height and serum creatinine, using a modified correlate.
Main Outcome Measures:
Reliability of CCr was assessed by two approaches. First, we compared each serial measurement with the mean value for each patient and thereby assessed the "intramethodical" variability. Second, we compared each CCr with the simultaneous formula clearance and assessed the "intermethodical" disagreement.
Results:
Twenty-seven percent of the measurements of CCr were classified as unreliable based on a comparison with the mean value for each patient. Reliability was closely correlated with residual renal function (p < 0.01); only 12% of the measurements in the anuric patients were classified as unreliable (vs 31% in the patients with residual renal function). The simultaneous formula clearance was less variable than the CCr. The formula clearance had a sensitivity of 93% and a specificity of 60% for detecting unreliable values of CCr.
Conclusion:
Estimation of total CCr is unreliable in pediatric patients on PD. A simultaneous formula clearance can be used to detect which values are unreliable.