Patients with chronic kidney disease (CKD) may have non-linear serum creatinine concentration (SC) trajectories, especially as CKD progresses. Variability in SC is associated with renal failure and death. However, current methods for measuring SC variability are unsatisfactory because they blend information about SC slope and variance. We propose an improved method for defining and calculating a patient's SC slope and variance so that they are mathematically distinct, and we test these methods in a large sample of US veterans, examining the correlation of SC slope and SC non-linearity (SCNL), and the association of SCNL with time to stage-4 CKD (CKD4) and death. We found a strong correlation between SCNL and rate of CKD progression, time to CKD4 and time to death, even in patients with normal renal function. We therefore argue that SCNL may be a measure of renal auto-regulatory dysfunction that provides an early warning sign for CKD progression.
- serum creatinine variability
- acute kidney injury
- chronic kidney disease progression
- Copyright © 2016, American Journal of Physiology - Renal Physiology