The Mildly Elevated Serum Bilirubin Level is Negatively Associated with the Incidence of End Stage Renal Disease in Patients with IgA Nephropathy

• DOI: 10.3346/jkms.2009.24.s1.s22
• Publication Date: 2009-01-30T05:08:47Z
• Authors: Ho Jun Chin; Hyun Jin Cho; Tae Woo Lee; Ki Young Na; Kook Hwan Oh; Kwon Wook Joo; Hyung Jin Yoon; Yon-Su Kim; Curie Ahn; Jin Suk Han; Suhnggwon Kim; En Sil Jeon; Dong Chan Jin; Yong-Lim Kim; Sun-Hee Park; Chan-Duck Kim; Young Rim Song; Seong Gyun Kim; Yoon Goo Kim; Jung Eun Lee; Yoon Kyu Oh; Chun Soo Lim; Sang Koo Lee; Dong-Wan Chae; Won Yong Cho; Hyoung Kyu Kim; Sang-Kyung Jo
• Keywords: Adult; Male; Risk; 0301 basic medicine; Incidence; Bilirubin; Glomerulonephritis, IGA; Middle Aged; 3. Good health; 03 medical and health sciences; Treatment Outcome; Risk Factors; Hypertension; Disease Progression; Humans; Kidney Failure, Chronic; Original Article; Female; Glomerular Filtration Rate

Oxidative stress plays various roles in the development and progression of IgA nephropathy, while bilirubin is known as a potent antioxidant. We therefore hypothesized that serum bilirubin would be associated with renal prognosis in IgA nephropathy. The study subjects comprised 1,458 adult patients with primary IgA nephropathy in Korea. We grouped patients according to the following quartile levels of bilirubin: <0.4 mg/dL (Q1), 0.4-0.5 mg/dL (Q2), 0.6-0.7 mg/dL (Q3), and >0.8 mg/dL (Q4). The outcome data were obtained from the Korean Registry of end-stage renal disease (ESRD). Eighty patients (5.5%) contracted ESRD during a mean follow-up period of 44.9 months. The ESRD incidences were 10.7% in Q1, 8.2% in Q2, 2.8% in Q3, and 2.8% in Q4 (p<0.001). The relative risk of ESRD compared to that in Q1 was 0.307 (95% confidence interval [CI], 0.126-0.751) in Q3 and 0.315 (95% CI, 0.130-0.765) in Q4. The differences of ESRD incidence were greater in subgroups of males and of patients aged 35 yr or more, with serum albumin 4.0 g/dL or more, with normotension, with eGFR 60 mL/min/1.73 m(2) or more, and with proteinuria less then 3+ by dipstick test. In conclusion, higher bilirubin level was negatively associated with ESRD incidence in IgA nephropathy.