Peritoneal Dialysis Associated Peritonitis Rate – Validation of a Simplified Formula

Abstract

Peritonitis is the most important therapy-related complication of peritoneal dialysis (PD). Unfortunately, many PD centers around the world do not accurately record peritonitis rate, mainly because they cannot ascertain PD patient time-at-risk from “patient flow” data - that is, calculating PD patient-days from dates when patients start and finish PD. We propose a simplified method of calculating PD peritonitis rate using PD patient time-at-risk from “patient stock” data - - that is, calculating PD patient-days from the number of prevalent PD patients at the center at the start of the year and the corresponding number at the end. We compared gold-standard measurements of annual PD peritonitis rates with simplified ones in the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) / New Zealand (NZ) PD Registry, and Le Registre de Dialyse Péritonéale de Langue Française et hémodialyse à domicile (the RDPLF). A total of 268 centers from 9 countries with 4311 center-years and 110,185 patient-years of follow-up were modelled. Overall agreement was excellent with a concordance correlation coefficient of 0.978 (95% confidence interval [CI] 0.975-0.980) in ANZDATA / NZ PD Registry, and 0.978 (0.977-0.980) in the RDPLF. There was statistically significant lower agreement for smaller centers in the registries at 0.972 (0.966-0.976) and 0.973 (0.970-0.976) respectively, although the performance of the simplified formula remains clinically sound in even these centers. The simplified method of calculating PD peritonitis rate is accurate, and will allow more centers around the world to measure, report, and work on reducing PD peritonitis rates.

ISPD peritonitis guideline recommendations: 2022 update on prevention and treatment

“…A recent study has proposed an alternative simplified formula for calculating peritonitis rates in which the denominator of patient years at risk is replaced by the average of the numbers of patients at the start and beginning of a year. 29 While this demonstrated reasonable overall agreement against the gold standard method when analysing Australian, New Zealand and French registry data, we suggest that peritonitis rates only be calculated using the gold standard method (i.e. number of episodes per patient year at risk) for the purpose of benchmarking using a standardised approach, and because the accuracy of the simplified method is sensitive to centre characteristics (i.e.…”

Simplified calculation of month-on-month annualized peritoneal dialysis associated peritonitis rate – Validation in ANZDATA, NZ PD and RDPLF registries

“…Nous avons évalué la concordance entre le gold-standard et les taux mensuels estimés de péritonite en DP à l'aide de statistiques de concordance. Comme nous l'avons décrit dans notre article précédent [2], le cadre de l'échelle des relations sous-tend la mise en oeuvre par Lin du coefficient de corrélation de concordance (CCC), qui combine des mesures de précision (coefficient de corrélation de Pearson) et d'exactitude (facteur de correction des biais). La combinaison de ces statistiques décrit dans quelle mesure les données observées s'écartent sur la ligne de concordance parfaite (c'est-à-dire la ligne à 45 degrés sur un nuage de points carré).…”

“…Cela permet de calculer les taux de péritonite en l'absence de données précises sur le «flux de patients» (c'est-à-dire la connaissance des dates auxquelles chaque patients est présent en DP dans la période), tant qu'il existe des données fiables sur le «stock de patients» ( le nombre de patients prévalents en DP à des moments donnés). [2].…”

Simplified calculation of peritoneal dialysis-associated peritonitis rate: Accuracy of a recently developed estimating equation

“…the numbers of patients on PD at given points in time) instead of 'patient flow' data (i.e. the dates when patients start and finish PD), 2 that is, Number of PD peritontis episodes during year for N patients at a given center…”

“…the numbers of patients on PD at given points in time) instead of ‘patient flow’ data (i.e. the dates when patients start and finish PD), 2 that is,…”