Ab1396 the Prognosis of Renal Function and Hydronephrosis in a Large Cohort of Idiopathic Retroperitoneal Fibrosis Patients: A Retrospective Study

Background: Hydronephrosis is common in idiopathic retroperitoneal fibrosis (iRPF) patients[1].Implantation of stent can quickly relieve ureteral obstruction but may cause complications[2]. For some patients, the hydronephrosis may relieve soon after steroid treatment and may not need stent. Objectives: To investigate the prognosis of hydronephrosis and renal function in a large cohort of iRPF patients with hydronephrosis but without catheterization. To explore if patients with certain characters may not need stent implantation. Methods: This is a retrospective cohort study. Patients diagnosed of iRPF with hydronephrosis were enrolled. Patients who followed up shorter than 3 months were excluded.The demography characteristics, baseline and follow-up clinical features and laboratory data were collected. The primary endpoint was the renal function at one year. The secondary outcome was the remission of hydronephrosis. We matched all patient into two groups by using Propensity Score Matching (PSM). Results: 266 patients were enrolled. All patients received steroids with or without immunosuppressive agents. 72 patients did not receive ureteral stenting, and 57/72(79.2%)patients attained hydronephrosis relief after 3.27(1.20,7.60)months. The baseline characteristics of patients with hydronephrosis who relieved and not relieved were demonstrated in Table 1. Patients who did not attain hydronephrosis relief kept renal function stable. In those who attained hydronephrosis relief, 6/52 (11.54%) patients' renal function got worse. The eGFR was the risk factor of not attaining hydronephrosis relief(HR=0.128,95%CI 0.021-0.769, P=0.025) according to Cox's proportional hazards regression model. We compare the prognosis between patients who indwelled ureteral stent or not. There were 58 patients in each group after PSM. No significant difference in renal function was found between the two groups. Conclusion: Most iRPF patients with mild hydronephrosis could get relief and preserve good renal function treatment of steroid. They may not need stent implantation. REFERENCES: [1] Vaglio A, Maritati F. Idiopathic Retroperitoneal Fibrosis. J Am Soc Nephrol. 2016;27(7):1880-1889. [2] Moroni G, Gallelli B, Banfi G, Sandri S, Messa P, Ponticelli C. Long-term outcome of idiopathic retroperitoneal fibrosis treated with surgical and/or medical approaches. Nephrol Dial Transplant. 2006;21(9):2485-2490. Table 1. Predictive factors for successful remission of hydronephrosis. ESR, erythrocyte sedimentation rate; CRP, C-reactive protein; IgG4, immunoglobulin G4;Scr, Serum creatinine concentration; eGFR, estimated glomerular filtration rate. Acknowledgements: This work was supported by the Peking University First Hospital. We also thank every doctor in our department for collecting paitents'demography characteristics, baseline and follow-up clinical features and laboratory data. Disclosure of Interests: None declared.