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Reliability of endogenous markers for estimation of residual renal function in haemodialysis patients
Author(s) -
Kjaergaard Krista D.,
Rehling Michael,
Jensen Jens D.,
Jespersen Bente
Publication year - 2013
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/cpf.12018
Subject(s) - renal function , cystatin c , medicine , urea , creatinine , urology , urine , reproducibility , endocrinology , chemistry , chromatography , biochemistry
Summary Background Residual renal function in haemodialysis patients is of increasing interest. However, reproducibility and agreement between methods to measure and estimate glomerular filtration rate ( GFR ) require further elucidation. The aim of this study was to evaluate the accuracy and reproducibility of GFR estimates based on endogenous markers in haemodialysis patients. Methods Twelve patients were examined twice. GFR was estimated by (i) urine clearances of creatinine, urea and the average of creatinine and urea clearance [ U ‐Cl(crea‐urea)]; (ii) an equation based on serum concentration of cystatin C [e GFR ( C ys C )]. These were compared to 51 C r‐ EDTA clearance in plasma [ P ‐ C l( EDTA )] and urine [ U ‐ C l( EDTA )]. Results U ‐ C l(crea‐urea) produced results similar to U ‐ C l( EDTA ). e GFR ( C ys C ) had a low week‐to‐week variability. Visually, e GFR ( C ys C ) differed from y = x when compared to the other methods indicating bias, probably due to extrarenal elimination of cystatin C . Coefficients of variation were significantly different, P <0·001: P ‐ C l( EDTA ), 10%; U ‐Cl(EDTA), 13%; and U ‐ C l(crea‐urea), 13%. P‐ C l( EDTA ) was 2·1 ml min −1 1·73 m −2 higher than U ‐ C l( EDTA ) (mean). Conclusions Glomerular filtration rate in haemodialysis patients can be estimated from U ‐ C l(crea‐urea) when complete urine collection is performed. The available e GFR ( C ys C ) in haemodialysis patients seemed to be biased, and further development and validation is desirable. P ‐ C l( EDTA ) was the most reproducible method and might be useful in special situations.