Implementing the European Renal Best Practice Guidelines suggests that prediction equations work well to differentiate risk of end-stage renal disease vs. death in older patients with low estimated glomerular filtration rate.
Department of Clinical and Molecular Medicine, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Nephrology, St. Olav Hospital, Trondheim, Norway. Electronic address: firstname.lastname@example.org.
Recent European guidelines suggest using the kidney failure risk equation (KFRE) and mortality risk equation for kidney disease (MREK) to guide decisions on whether elderly patients with chronic kidney disease should be referred early for dialysis preparation. However, the concurrent use of the two risk equations has not been validated. To do so we evaluated 1,188 individuals over five years with estimated glomerular filtration rate (eGFR) under 45ml/min/1.73m2 and age over 65 years from the Norwegian population based HUNT study. Forty-two patients started renal replacement therapy and 462 died as their first clinical event. The KFRE was well calibrated (mean risk estimate 4.9% vs observed 3.5%) with high diagnostic accuracy (C-statistics 0.93). The MREK underestimated death risk in those with lower risk (mean risk estimate 30.1% vs observed 38.9%) and had moderate diagnostic accuracy (C-statistics 0.71). Only 31 individuals had estimated end stage kidney disease (ESRD) risk greater than death risk, and most experienced ESRD before death. Only two of 598 patients over 80 years old, and ten of 1,063 with eGFR 25-45ml/min/1.73m2 at baseline experienced ESRD. Decision curve analysis demonstrated that for risk adverse patients, deferring ESRD preparation may be appropriate until predicted ESRD risk exceeds predicted death risk. For those preferring a more aggressive approach, referral when eGFR is under 25 ml/min/1.73m2 may be beneficial if age remains under 80 years. Thus, the risk of ESRD is low compared to the risk of death in many older patients with chronic kidney disease stage 3b or worse, and combination of predicted ESRD and death risks, eGFR levels, age, and the patient`s valuations of harm and benefit can be helpful for deciding when to start dialysis preparations.