To screen statistical methods that are suitable for studying risk factors of peritoneal dialysis-related peritonitis so as to provide new ideas for clinical research of peritonitis.

Nine statistical models were selected for comparative analysis, including six models without time-dependent covariates: logistic regression, Poisson regression, negative binomial regression, COX regression, AG model, and PWP-CP model; and three models with time-dependent covariates: COX regression, AG model, and PWP-CP model. The statistical data were obtained from patients with end-stage renal disease who started peritoneal dialysis treatment from January 2013 to December 2016 in the Peritoneal Dialysis Center of The First Medical Center, Chinese PLA General Hospital. The data were collected until December 2018. Through the analysis of the clinical characteristics of peritonitis, and the comparison between the statistical models and results, the suitable statistical model was selected.

From the clinical data of peritonitis, as a dependent variable, the peritonitis event consists of three elements: "time of occurrence" , "number of occurrences" , and "order of occurrence" . As independent variables, most of the covariates were time-dependent. The three-dimensional dependent variables and the varying independent variables together constituted complex clinical data. In terms of data integrity, only the PWP-CP model could include the "three elements of peritonitis" . In terms of statistical models fitting, the Poisson model was too discrete to enter the data of this study. The model based on the time-dependent covariates was better to fit than the model using the baseline data. In terms of statistical results, the model with time-dependent covariates avoided the bias caused by the simple use of baseline data, making the statistical results closer to the real situation.

In the study of risk factors of peritonitis, more realistic research results could be obtained only by ensuring the integrity and accuracy of the data as much as possible. In this study, by analyzing the data of peritonitis and comparing the statistical results of each model, it was found that the PWP-CP model with time-dependent covariates was more suitable for studying the risk factors of peritonitis.