Supplementary Material for: Early-onset peritonitis and outcomes of peritoneal dialysis: A cohort study with data from the RDPLF

Introduction
Peritonitis occurring within the first months on peritoneal dialysis (PD) has been associated with poorer PD outcomes. Whether early peritonitis is a risk factor for transfer to haemodialysis in the long term is a matter of investigation.

Methods
This retrospective study was conducted using data from the French Language PD Registry of incident PD patients between 2002 and 2018. Early-onset peritonitis (EOP) was defined as peritonitis occurring during the first 3 months on PD. Our hypothesis was that EOP was associated with an increased risk of transfer to haemodialysis during the first months on PD but that it was no longer associated with an increased risk of transfer to haemodialysis several months after the start of PD. The associations between EOP and the different outcomes were explored via time-dependent coefficient Cox regression and Fine and Gray regression.

Results
EOP was associated with an increased risk of PD cessation by transfer to haemodialysis within the first 12 months of PD and beyond (<12 months cs-HR 1.50, 95% CI 1.36–1.66 and >12 months cs-HR 1.17, 95% CI 1.06–1.28, respectively).

Conclusion
EOP is associated with a greater risk of PD cessation due to transfer to haemodialysis, especially within the first year after peritonitis occurrence, and with a persistent effect in the long term. Reducing or delaying EOP, notably through its systematic reporting and monitoring as a KPI to help in the implementation of QIPs, could have a favourable impact on patient-level outcomes.