First, cause-specific death was not available in this study. Second, RKF measurement is not accurate given the use of CLurea and not the average of renal urea and creatinine clearances and the difficulties in complete collection of urine samples and its punctuality in patient daily life. The use of factor 0.9 for predialysis serum urea nitrogen for renal CLurea calculation might have also induced errors to some extent. Nevertheless, the population-level associations with clinical outcomes can be estimated from an adequate number of subjects if such errors are not associated with the outcome. Third, available RKF measures may not be representative of those in the entire hemodialysis population, because patients on dialysis with limited or no RKF are less likely to have undergone urine collections, especially at 1 year after hemodialysis initiation. Continue Reading We know several other limitations within analysis