L SKEAT1, R MASTERSON1, A TJIPTO2, C KARSCHIMKUS1, N TOUSSAINT1
1Royal Melbourne Hospital, Parkville, Australia, 2Barwon Health, Geelong, Australia
Background: Residual renal function (RRF) provides substantial volume and solute clearance even after dialysis initiation. Preservation of RRF is associated with improved outcomes including mortality in both peritoneal and haemodialysis (HD) patients. Factors predicting RRF loss are unclear, including HD modality. Nocturnal haemodialysis (NHD) may cause less aggressive fluid/solute shifts however retrospective data suggests frequent NHD may accelerate RRF decline.
Aim: To determine if decline in RRF differs between patients undergoing conventional HD (CHD) versus NHD.
Methods: A prospective observational study of incident HD patients was undertaken at 2 institutions to assess changes in RRF comparing patients undertaking CHD (4-5hrs, 3days/week) and NHD (8hrs, 3-5nights/week). Change in RRF was measured by 48-hr urine collections and glomerular filtration rate (GFR) measured by nuclear scans (Cr51-EDTA) at initiation of dialysis (baseline) and at 12 months.
Results: A total of 18 patients were recruited (8 CHD, 10 NHD), mean age 60.7+/-9.2yrs, 67% male, mean BMI 29.2+/-4.9kg/m2, 39% diabetic. 3 patients withdrew after baseline therefore 15 patients completed the study. Mean nuclear GFR at baseline and 12mths was 13.4+/-4.4 and 9.8+/-3.4 ml/min respectively (p=0.02), with no significant difference in rate of change between patients on NHD vs CHD. Over 12mths, creatinine clearance (16.5+/-8.3 to 6.0+/-4.2ml/min) and urea clearance (2.7+/-2.1 to 1.4+/-1.6ml/min) also decreased (p<0.001 and p=0.05 respectively), although with no difference between HD groups. There was also no difference in serum beta2microglobulin between HD groups at 12mths, but a trend towards less urine volume in those on CHD (p=0.06).
Conclusion: Our small prospective cohort study found no difference in RRF decline between HD modalities. Further studies are required to elucidate dialysis strategies for preservation of RRF.
Lee Skeat is a current renal advanced trainee at Royal Melbourne Hospital