#1513 Update on the peritonitis trend in central Spain

Abstract Background and Aims Peritonitis is one of the most common and severe complications associated with peritoneal dialysis (PD) traditionally cited as the primary cause of catheter loss and discontinuation of the dialysis technique. Nevertheless, the incidence and severity of peritonitis has been significantly reduced over time. Therefore, we aimed to update the current impact of peritonitis in PD patients. Method We performed an observational, multi-centre, prospective cohort including 3,037 patients who started PD between 2003-2020 followed for a median of 1.6 [0.8-2.9] years. Results We observed 2 941 episodes of peritonitis, with a peritonitis rate (PR) of 0.46 episodes per patient year and a mean of 2.6 years CI 95% [2.4-2.8] to first peritonitis episode. As expected, gram-positive organism was identified in the 69.3% of the cases, followed by gram-negative (19.6%) and sterile culture (15.6%). The usual course of the peritonitis is favourable, with complete recovery in the 76.4% of the cases, whereas just the 37.6% require admission during a median of 5 [3-9] days, with a peritonitis recurrence of 11.2%. A fatal peritonitis (resulted in PD cessation) was observed in 11.7% of the patients with an overall mortality of 0.7% (considering all the deaths within the 90 days after peritonitis). Factors associated with a 90-days mortality rate related to PD rate were age > 65 years (OR 2.99 [1.84-4.85]), Charlson index (OR 1.19 [1.07-1.33]), and the type of microorganism: fungus (OR 9.8 [4.16-23.43], multi-bacterial (OR 7.97 [0.91-69.88] and gram- negative OR (2.41 [1.45, 3.99]). Comparing patients who developed peritonitis (P) (N = 1230) vs patients who not developed peritonitis (NP) (N = 1807), P patients were older (P 59 ± 15.5 years vs NP 55 ± 15.5 years, p < 0.001) and associated higher comorbidity (such as Charlson index, cardiovascular and diabetes mellitus history) than NP patients. P patients more commonly had a prior history of renal replacement therapy (kidney transplant P 9.2% vs NP 6.9% and hemodialysis 18.8% vs 17.1%) compared with NP patients. PR has significantly decreased over three consecutive 5-year periods: from 0.51 [0.48-0.54] peritonitis cases per year during 2003-2008 to 0.45 [0.43-0.48] during 2009-2014 (p 0.03), and further dropping to 0.41 [0.38-0.44] for the period 2015-2020 (p < 0.001). Conclusion Over the past 17 years, the incidence and severity of peritonitis have significantly reduced, despite PD patients becoming older and associated high comorbidities.