Idiopathic retroperitoneal fibrosis: a cross-sectional study of 142 Chinese patients.

Objective: To investigate the epidemiological, clinicolaboratory, imaging, and therapeutic characteristics of idiopathic retroperitoneal fibrosis (iRPF) in China.Method: All patients presenting to the Chinese People's Liberation Army General Hospital from October 1996 to July 2016 diagnosed with iRPF were included. Data were collected from medical records and the smoking index was calculated. Scheel radiological classification was used to assess the extent of soft-tissue density.Results: The study included 142 patients (120 men, 22 women). The mean age was 54.3years. Disease duration ranged from 0.23 to 109.5months (median 2.7). Current smoking rate was 53.5%. Flank pain was more common in males (p=0.041) and in the high smoking index group (p=0.03). C-reactive protein level ranged from 0.08 to 8.9mg/dL (median 1.9). Serum immunoglobulin G(4) (IgG(4)) was elevated in 31/63 patients (49.2%), and males had higher IgG(4) concentrations (p=0.017) at presentation. Respectively, 44.4%, 5.6%, and 22.5% of cases were classified into Scheel classes I, II, and III. Eight patients (5.6%) had atypical RPF localization and 103 (72.5%) presented with hydronephrosis, which was more common in class III patients (p=0.04). Nine patients (6.3%) received no treatment; the others received medical (34.5%) or surgical treatment (14.8%), or both (44.4%).Conclusions: There was a higher rate in males and younger age at disease onset in these Chinese iRPF patients than in other populations. Acute-phase reactants and serum IgG(4) were elevated in some patients. Tobacco use may be a risk factor for iRPF in Chinese populations.