Patterns and Predictors of Kidney Function Decline in the Last Year prior to Dialysis

Abstract

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.

Is a decline in estimated GFR an appropriate surrogate end point for renoprotection drug trials?

“…Patients with polycystic kidney disease may have less RFT variability, while patients with cardiovascular disease may be more likely to have nonlinear RFT. 18 Although diabetics are assumed to have faster RFT declines, similar RFTs are seen in diabetics and nondiabetics at comparable levels of albuminuria. 19 Patients with eGFR >60 ml/min/1.73 m 2 may have greater RFT variability and may need mGFR to assess renal function changes over time.…”

Renal Function Trajectory Is More Important than Chronic Kidney Disease Stage for Managing Patients with Chronic Kidney Disease

“…Patients with a slower trajectory (BT <3 ml/min/1.73 m 2 /year) may require less intensive follow-up [81]. On the other hand, in one study, almost half of the patients had a nonlinear decline in renal function in the year prior to dialysis initiation [82]. A difference in rate of eGFR decline per year of 1 ml/min/1.73 m 2 can have a very powerful effect on the timeframe to start RRT.…”

Nonlinear Trajectory of GFR in Children before RRT

“…Given the convenience of assuming a linear GFR trajectory, which results from the ease of modeling and interpreting linear slopes, few studies have sought to validate the linearity assumption and explore the possibility of nonlinear GFR decline. However, nonlinearity in GFR decline has been observed in some epidemiologic studies, [5][6][7] and the implications on the risk for adverse outcomes have generated interest. 8 A CKD cohort study in France found that about one half of its patients experienced nonlinear GFR decline during the last year before dialysis.…”

“…8 A CKD cohort study in France found that about one half of its patients experienced nonlinear GFR decline during the last year before dialysis. 5 A study by Li et al 9 used a flexible approach to model nonlinearity in GFR trajectories. Li et al 9 found evidence of nonlinear GFR trajectory behavior in adult patients with CKD, and furthermore, the probability of having nonlinear features in an individual trajectory was associated with known risk factors for CKD progression.…”

“…O'Hare et al 10 found that rates of recommended pre-ESRD care were lower for those patients experiencing the most rapid progression before dialysis initiation. Ambrogi et al 5 suggested that nonlinear patterns in GFR decline might create difficulty in estimating the timing of dialysis. These results may also highlight the coarseness of current methods for assessing the impact of risk factors on CKD progression, which mainly rely on the assumption of linear decline in kidney function.…”