Estimating risk of encapsulating peritoneal sclerosis accounting for the competing risk of death

Background: Risk of Encapsulating Peritoneal Sclerosis (EPS) is strongly associated with the duration of peritoneal dialysis (PD), such that patients who have been on PD for some time may consider elective transfer to haemodialysis to mitigate risk of EPS. There is a need to determine this risk to better inform clinical decision-making, but previous studies have not allowed for the competing risk of death.

Methods: This study included new adult PD patients in either Australia and New Zealand (ANZ 1990-2010) or Scotland (2000-2008) followed until 2012. Age, time on PD, primary renal disease, gender, dataset and diabetic status were evaluated as predictors at start of PD, then at three and five years after starting PD using flexible parametric competing risks models.

Results: In 17,396 patients (16,162 ANZ, 1,234 Scotland), EPS was observed in 99 (0.57%) patients less frequently in ANZ patients (n=65, 0.4%) than in Scottish patients (n=34, 2.8%). The estimated risk of EPS was much lower when the competing risk of death was taken into account (1-KM=0.0126, CIF=0.0054). Strong predictors of EPS included age, primary renal disease and time on PD. The risk of EPS was reasonably discriminated at the start of PD (C-statistic = 0.74 to 0.79) and this improved at 3 and 5 years after starting PD (C-statistic = 0.81 to 0.92).

Conclusions: EPS risk estimates are lower when calculated using competing risk of death analyses. A patient’s estimated risk of EPS is country-specific, and can be predicted using age, primary renal disease and duration of PD.