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

David W Johnson,Simon J Davies,Ivonne Solis-Trapala,Hilary L Bekker,Martin Wilkie,Louise Phillips-Darby,Mark Lambie,Lucy Teece,Robert Mactier,Michaela Petrie,Ken Tupling,John Belcher

doi:10.1093/ndt/gfz034

Abstract

BackgroundRisk 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 the 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.MethodsThis study included new adult PD patients in Australia and New Zealand (ANZ; 1990–2010) or Scotland (2000–08) followed until 2012. Age, time on PD, primary renal disease, gender, data set and diabetic status were evaluated as predictors at the start of PD, then at 3 and 5 years after starting PD using flexible parametric competing risks models.ResultsIn 17 396 patients (16 162 ANZ, 1234 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 Kaplan–Meier = 0.0126, cumulative incidence function = 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 = 0.74–0.79) and this improved at 3 and 5 years after starting PD (C-statistic = 0.81–0.92).ConclusionsEPS 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.

Highlights

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 the risk of EPS
Encapsulating peritoneal sclerosis (EPS) is a serious, uncommon condition predominantly affecting patients exposed to peritoneal dialysis (PD)
We have demonstrated that estimation of EPS risk is strongly affected by death as a competing event and that statistical techniques need to take this into account

Summary

Introduction

Encapsulating peritoneal sclerosis (EPS) is a serious, uncommon condition predominantly affecting patients exposed to peritoneal dialysis (PD). Due to the strong association between EPS and longer periods of exposure to PD treatment [1,2,3], an important management question for patients is when the risk of future EPS becomes sufficiently high to justify switching to haemodialysis (HD) to mitigate this risk. Appropriate decisions require accurate assessment of the risk of EPS, including an accurate estimation of the impact of exposure time of PD on EPS risk. Appropriate clinical judgements and shared decisions with patients require an accurate risk assessment of EPS informed by a patient’s clinical indicators rather than population-based associations between incidence and exposure to PD treatment. A patient’s estimated risk of EPS is country-specific and can be predicted using age, primary renal disease and duration of PD

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Results

Conclusion