[Evaluation of long-term monitoring of glomerular filtration in individuals with kidney transplantation].

BACKGROUND

Long-term follow-up of the glomerular filtration rate (GFR) in subjects with a transplanted kidney revealed that changes of this function in the course of time are frequently irregular and cannot be expressed by a simple mathematical function. This fact causes problems when evaluating the rate of progression of chronic transplant nephropathy. Characterization of changes of the GFR of the graft by values of this function at the beginning and at the end of the follow-up period does not take into account transient changes and the predominating level of GFR during the entire follow-up period. The authors tried to elaborate a method which would render it possible to evaluate in a simple manner the level of the GFR during the entire investigation period. The method is based on assessment of the area under the curve (AUC) of GFR.

METHODS AND RESULTS

This method was used to investigate the time course of GFR in 22 subjects after transplantation of the kidney from a cadaverous donor. The investigated group included nine women and 13 men aged 30-65 years (mean 50 years). The time interval after transplantation was 1-84 months (mean 22 months). The GFR was assessed after 3-months intervals for a period of 9-21 months (mean 13.5 months). GFR was assessed on the basis of renal clearance of polyfructosan. The time course and level of GFR was evaluated in the common way based on GFR values at the beginning and end of the investigation period and according to the new method based on calculation of AUC. It was found that the two methods of evaluation of graft function do not provide the same results. In one third of the examined subjects the differences were higher than 20%.

CONCLUSIONS

The results of this study provide evidence that evaluation of changes and the level of the GFR of the graft throughout the follow-up period based on AUC provides more detailed information then evaluation of the GFR only at the beginning and end of the follow-up period. The authors assume that this method of evaluation of the GFR of the graft could be helpful in a more accurate assessment of the effect of different therapeutic procedures.