Abstract: Objectives   To investigate the clinical characteristics and prognosis of peritoneal dialysis-associated peritonitis (PDAP) in patients with different dialysis duration.  Method  A total of 166 peritoneal dialysis (PD) patients who experienced the first episode of PDAP in Peking University People's Hospital from January 2007 to October 2021 were retrospectively reviewed. According to PD duration, patients were divided into long PD duration group (≥60 months), medium PD duration group (36-59 months) and short PD duration group (＜36 months). Clinical characteristics and PDAP prognosis were collected and analyzed. Results  Among 166 patients，83(50%) were male and the mean age was (63.33±12.14) years. The major primary renal diseases were diabetic nephropathy(35.5%).There were 36 patients (21.7%) in long PD duration group. With the extension of PD duration, the proportion of patients with diabetes gradually decreased (62.1%, 45.7%, 30.6%, χ2=11.068, P=0.004), and the treatment failure rate and PDAP-related mortality gradually increased(χ2=10.095、11.171，P=0.005, 0.003). Logistic multivariate regression analysis showed that PD duration was not only independent risk factor for the treatment failure of the first-episode PDAP (OR1.291，95%CI : 1.048～1.591,P=0.016) , but also independent risk factor for first-episode PDAP death (OR: 1.675, 95%CI:1.262～2.222, P＜0.001).   Conclusion   Patients with PD duration of ≥60 months had the highest rate of treatment failure and PDAP-related mortality when they first experienced PDAP. PD duration is an independent risk factor for the first episode of PDAP treatment failure and death. The prevention of peritonitis in PD patients with long PD duration should be actively strengthened.

Key words: Peritoneal dialysis, Peritoneal dialysis-associated peritonitis, Long dialysis duration