Background: Peritonitis is more common in peritoneal dialysis (PD) patients nonadherent to the PD exchange protocol procedures than in compliant patients. We therefore investigated whether regular testing of PD knowledge with focus on infection prophylaxis could increase the time to first peritonitis (primary outcome) and reduce the peritonitis rate in new PD patients. Methods: This physician-initiated, open-label, parallel group trial took place at 57 centers in Sweden, Denmark, Norway, Finland, Estonia, Latvia, the Netherlands, and the United Kingdom from 2010 to 2015. New peritonitis-free PD patients were randomized using computer-generated numbers 1 month after the start of PD either to a control group ( n = 331) treated according to center routines or to a retraining group ( n = 340), which underwent testing of PD knowledge and skills at 1, 3, 6, 12, 18, 24, 30, and 36 months after PD start, followed by retraining if the goals were not achieved. Results: In all, 74% of the controls and 80% of the retraining patients discontinued the study. The groups did not differ significantly regarding cumulative incidence of first peritonitis adjusted for competing risks (kidney transplantation, transfer to hemodialysis and death; hazard ratio 0.84; 95% confidence interval (CI) 0.65–1.09) nor regarding peritonitis rate per patient year (relative risk 0.93; 95% CI 0.75–1.16). Conclusions: In this randomized controlled trial, we were unable to demonstrate that regular, targeted testing and retraining of new PD patients increased the time to first peritonitis or reduced the rate of peritonitis, as the study comprised patients with a low risk of peritonitis, was underpowered, open to type 1 statistical error, and contamination between groups.
