Rapid Change in Residual Renal Function Decline is Associated with Lower Survival and Worse Residual Renal Function Preservation in Peritoneal Dialysis Patients

The survival advantage observed among peritoneal dialysis patients early on after dialysis initiation has been largely attributed to residual renal function (RRF) preservation due to higher baseline residual function and fewer comorbidities. We hypothesize that a rapid decline in RRF is associated with higher risk of anuria and mortality. In a retrospective cohort study of 581 subjects on peritoneal dialysis with longitudinal prevalent data, we assessed whether RRF change over time, in addition to baseline RRF, increased risk of mortality and anuria using Kaplan-Meier analysis and Cox proportional hazard analysis to control for known risk factors. Rapid RRF decline (≥ 0.09 decline) over a 12-month period was associated with a 2.6-fold increase in the risk of death (hazard ratio [HR] 2.60, 95% confidence interval [CI] 1.66 – 4.07, compared with < 0.09 decline) and a 2-fold increase in anuria (HR 2.06, 95% CI 1.24 – 3.42). Each quartile of increasing severity of RRF decline over a 12-month period increased risk incrementally for death (2 nd quartile: HR 3.04, CI 1.26 – 7.34; 3 rd quartile: HR 4.01, CI 1.71 – 9.83; 4 th quartile HR 5.78, CI 2.10 – 15.9) and generally for anuria (quartiles with HR 5.72 – 7.21). The escalating risk of mortality and anuria was greater for those with diabetes mellitus. In conclusion, rapid decline in RRF over a 12-month period increased the risk of mortality and likewise anuria, beyond previously established risk factors for mortality and anuria. The impact on mortality and RRF preservation was particularly severe for those with diabetes mellitus.