High Versus Low Visit-to-visit Variability in Estimated Glomerular Filtration Rate Predicts Progression to End-stage Renal Disease

Background: It is known that subtle increases in serum creatinine (sCr) levels affect prognosis in patients with acute kidney injury. However, the impact of visit-to-visit variability in estimated glomerular fi ltration rate (eGFR) on renal prognosis is not understood. Methods: We studied 215 pre-dialysis patients attending our clinic who had more than 4 serial sCr measurements before 24-hour ABPM between 2005 and 2011. To evaluate eGFR variability, we assessed the difference between observed eGFR value and slope predicted eGFR value and converted it into coeffi cient of variation value. The primary endpoint was progression to end-stage renal disease (ESRD), the initiation of maintenance dialysis, or uremic death with conservative management. Results: Among 215 patients with a median follow-up of 4.3 years, there were 39 ESRD events in the high eGFR variability group and 28 ESRD events in the low eGFR variability group (log-rank test, p = 0.047). Furthermore, high eGFR variability was shown to be a good predictor of progression to ESRD in a sub-analysis of patients with low proteinuria, a less steep eGFR slope, or without hypertension (log-rank test, p = 0.039, p = 0.048, p = 0.048, respectively). In multivariate Cox regression analysis, high proteinuria, low baseline eGFR, and steep eGFR trend but not high eGFR variability were signifi cantly associated with ESRD (p = 0.047, p = 0.001, p = 0.016, p = 0.31, respectively). Conclusion: High eGFR variability was a good marker of adverse renal prognosis in CKD patients, especially in patients with low proteinuria, slowly progressive CKD, or without hypertension. Further attention is warranted for ambulatory patients with large eGFR fl uctuations.