assessment of electrolyte free water clearance in renal transplant recipients

Background: few studies have been done on free water excretion capacity in renal transplant recipients. objectives: this study was designed to compare electrolyte free water clearance (e-ch2o) in renal transplant recipients with healthy control group. methods: a cross-sectional study was conducted to determine three-hour creatinine clearance (ccl), e-ch2 o, and percent urine output in 3 hours after administering 20 ml/kg oral water loading following 12-hour fasting, in 22 renal transplant recipients with good graft function (creatinine < 1.5 mg/dl) and 26 healthy controls. patients with diabetes mellitus, hypertension, ischemic heart disease, or liver disease, hypovolemia and hypoalbuminemia were excluded. statistical analysis was done using t-test, k-square, and pearson’s correlation test. results: we recruited 25 recipients (73% patients in living and 27% in cadaveric donor transplantation) and 26 healthy control groups.3 patients refused to collect urine and finally 22 patients finished the protocol. the mean age of subjects was 37.68 ± 13.88 and 31.40 ± 8.20 years old in renal transplant recipients and control groups, respectively. in patient group male to female ratio was 9/13 and in control group was14/12. although the 3h-ccl was similar (126.49 ± 53.52 vs. 109.99 ± 47.06 ml/min) in two groups (p > 0.05), the e-ch2o (1.83 ± 1.22 vs. 2.94 ± 2.02) and 3-hour urine output percent (55.93 ± 22.86 vs74.11 ± 30.38) in kidney recipients was significantly lower than healthy controls (p < 0.05). there wasn’t any significant correlation between e-ch2o and 3h-ccl in renal transplant recipients. donor source and gender did not affect 3h-ccl and e-ch2o in renal transplant patients. conclusions: this study demonstrated that e-ch2 o has been decreased in renal transplant patients in comparison with control group when there was not any difference between3h- ccl in two groups. this indicates that e-ch2 o may be decreased earlier than 3h-ccl in transplant patients.