How to assess the rate of progression of chronic renal failure in children?

Methodology for assessing progression of chronic renal failure and performing and analysing trials has never been a favourite topic in nephrology. The aim of this paper is to discuss from a statistician's point of view the advantages and disadvantages of different direct (glomerular filtration rate, creatinine clearance, reciprocal and serum creatinine) and indirect (need of renal replacement therapy, halving of glomerular filtration rate, doubling of serum creatinine) markers of renal function, and their statistical evaluation. The use of cross-tabulation, regression analyses/slope techniques and survival analyses for this purpose is discussed. Furthermore, a new approach for the evaluation of progression, the so-called progression charts, is described in detail. This paper reveals that analysing progression of renal failure is not an easy task. However, there are a number of pragmatic approaches which seem to be suitable.