Idiopathic Retroperitoneal Fibrosis-Related Hydronephrosis: Evaluation of Comprehensive Management and Prediction of Inflammatory Markers for Stent-Free Outcomes

Zixiong Huang,1– 3 Yanying Liu,4,5 Yunshu Xiao,5 Hao Hu,1,2 Tao Xu1,2 1Department of Urology, Peking University People’s Hospital, Beijing, 100044, People’s Republic of China; 2Applied Lithotripsy Institute, Peking University, Beijing, 100044, People’s Republic of China; 3Department of Urology, Michigan Medicine, Ann Arbor, MI, 48109, USA; 4Department of Rheumatology, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, People’s Republic of China; 5Department of Rheumatology and Immunology, Peking University People’s Hospital, Beijing, 100044, People’s Republic of ChinaCorrespondence: Hao Hu; Tao Xu, Department of Urology, Peking University People’s Hospital, 11 Xizhimen South Street, Beijing, 100044, People’s Republic of China, Email [email protected]; [email protected]: This study investigated the efficacy of comprehensive management and predictable inflammatory markers for idiopathic retroperitoneal fibrosis (iRPF)-related hydronephrosis outcomes.Methods: Patients with iRPF-related hydronephrosis underwent surgical (ureteral stent and/or nephrostomy tube placement) and medical (corticosteroid-based multiple immunosuppressants) management were classified according to stent-indwelling outcomes. Univariate analysis of clinical profiles was conducted to screen possible predictors of hydronephrosis remission.Results: In a series of 38 patients, 52.6% achieved hydronephrosis remission and stent/tube removal (stent-free group). The median indwelling time in the stent-free group (12 months) was significantly lower than that in the treatment-failure group (37 months, p< 0.05). Mean retroperitoneal mass diameters was significantly reduced (anteroposterior by 11.66 mm (95% CI 2.31– 21.01), transverse by 15.41 mm (95% CI 3.37– 27.46), suprainferior by 30.53 mm (95% CI 4.87– 56.19); p< 0.05) during the treatment course, in line with mean renal pelvis width (by 36.2%) and renal function parameters (serum creatinine by 16.9%, blood urea nitrogen by 12.9%). Renal function improved (36.9%) or remained stable (44.7%) in most patients, the mean estimated glomerular filtration rate increasing by 8.7% (from 55.4 mL/min/1.73 m2 to 60.2 mL/min/1.73 m2). At the initial diagnosis, median serum immunoglobulin IgG and CRP levels were significantly higher in the stent-free group than in the treatment-failure group (IgG 17.55 g/L vs. 13.50 g/L, CRP 19.60 mg/L vs. 3.15 mg/L; p< 0.05). Decline in serum IgG (− 5.80 g/L vs. − 2.30 g/L), CRP (− 18.93 mg/L vs. − 1.72 mg/L) and erythrocyte sedimentation rate (− 22.00 mm/h vs. − 1.50 mm/h) levels in the stent-free group surpassed those in the treatment-failure group (p< 0.05).Conclusion: Comprehensive management benefits iRPF patients with hydronephrosis by preserving renal function. The 24-month scale might guide stent/tube removal. Elevated inflammatory markers (IgG and CRP) at the initial iRPF diagnosis and IgG, CRP, and erythrocyte sedimentationrate (ESR) variations associated with hydronephrosis outcomes.Plain Language Summary: The 24-month scale might guide the decision of final removal.Elevated inflammatory markers (IgG and CRP) at initial iRPF diagnosis and IgG, CRP, and ESR decreasing during the treatment course could predict hydronephrosis remission and stent-free outcomes.Alternative treatments, such as immunosuppressants other than corticosteroids, rather than longer stent indwelling could be recommended for patients with minimal possibility of hydronephrosis remission.Keywords: idiopathic retroperitoneal fibrosis, hydronephrosis, ureteral stent, immunosuppressant medications, stent-free outcome