Estimated Glomerular Filtration Rate —A More Stable Indicator than Creatinine Clearance in Peritoneal Dialysis Practice

OBJECTIVE The usefulness of estimated glomerular filtration rate may not be restricted to pre-dialysis patients, since we reported that estimated glomerular filtration rate was well correlated with measured total creatinine clearance in peritoneal dialysis patients. To clarify the clinical usefulness of estimated glomerular filtration rate as a parameter for peritoneal dialysis adequacy, we retrospectively surveyed estimated glomerular filtration rate and total creatinine clearance in peritoneal dialysis patients treated at JA Toride Medical Center. PATIENTS AND METHODS A total of 114 data sets of estimated glomerular filtration rate and total creatinine clearance from 21 PD patients treated at JA Toride Medical Center were collected from November 2010 to October 2011. The patients consisted of 15 men and six women with an average age of 66.6 ± 12.6 years (46-95 years old). The average number of samples was 5.4 ± 1.5 (2 to 7) per patient. RESULTS The collected data showed less correlation of estimated glomerular filtration rate and total creatinine clearance (r. = 0.435) than that of a previous cross-sectional study (r. = 0.836). As reported in pre-dialysis patients, the differences between estimated glomerular filtration rate and total creatinine clearance were correlated with total creatinine excretion in urine and PD effluent (r. = 0.821). The differences were also correlated with normalized protein catabolic rate, which was one of the main determinant factors for total creatinine excretion (r. = 0.636). A similar tendency was apparently observed in one patient with poor compliance to diet therapy and fluctuating dietary intake. From the analysis of these data, serum creatinine seemed to fluctuate less possibly due to compensatory capacity of the residual renal function in small solute clearance. CONCLUSIONS Consequently, estimated glomerular filtration rate was turned out to be a more stable parameter than total creatinine clearance, which might be a desirable feature in long-term follow-up of peritoneal dialysis patients.