Patterns and predictors of kidney function decline in the last year prior to dialysis.

Background: Establishing a comprehensive characterization of kidney function decline before dialysis is necessary to predict dialysis onset and prepare patients for replacement therapy.

Aims: To investigate kidney function as measured by pattern and rate of decline in glomerular filtration rate (GFR) over the year preceding dialysis and to identify factors associated with a nonlinear GFR decline.

Methods: We enrolled patients beginning dialysis in Lorraine (France) in 2005 and 2006, who were referred to a nephrologist more than 4 months before dialysis and had received more than 3 predialysis serum creatinine tests. From medical records, we retrospectively collected demographic and clinical data, as well as biological data during nephrologist follow-up, limited to 1 year before dialysis. A curve of GFR evolution by time was drawn for each patient and his linearity was evaluated graphically and confirmed by R2 > 0.7. Factors associated with a nonlinear decline in GFR were identified by logistic regression.

Results: A total of 342 patients were included; the mean length of predialysis nephrologist care was 10.0 +/- 9.7 months and the median number of serum creatinine tests per patient was 9 . Among these patients, 185 (54.1%) showed a linear decline in GFR and 157 (45.9%) a nonlinear decline. Patients with cardiovascular disease were 2.6 times more likely to show a nonlinear than linear decline in GFR (p < 0.0001).

Conclusion: For patients with a linear decline in GFR, but not those with a nonlinear decline, date of dialysis onset can be estimated.