We thank Drs Neagu et al1 and Niel et al2 for their interest and comments on our work.3 Our purpose was not to predict estimated glomerular filtration rate (eGFR) but to describe individual patterns of eGFR decline, examine the frequency of deviations from a linear pattern, and identify factors associated with GFR stability that could be therapeutic targets. Interestingly, the long-term observations by Drs Neagu et al1 over a minimum of 10 years, although in a small number of patients, are very similar to our findings of a significant proportion of patients having nonlinear patterns and periods of stable GFRs, apparently unrelated to acute events, thus deserving further investigations.