Prediction of Steroid Responsiveness in Adult Minimal Change Nephrotic Syndrome Using Urinary beta2-Microglobulin

Chang, Kwang Yul; Woo, Young Seok; Han, Kyung Geun; Bae, Sung Jin; Kim, Seong Eun; Kim, Ki Hyun

Abstract

Urinary protein per se causes renal tubular injury and stimulates immunologic reaction. The extent of proximal tubular injury can be estimated by measuring the amount of 24 hours urinary beta2-microglobulin (U beta2-MG). The aim of this study was whether U beta2-MG level could predict the response to the initial steroid treatment for the patients with minimal change nephrotic syndrome (MCNS). We analyzed 58 adult patients (33 M, 25 F), aged 33+/-15 years (range 16-76), with biopsy-proven MCNS treated with 40 to 60mg of oral prednisolone daily up to 16 weeks. The responsiveness (44 cases) inculded complete and partial remission or steroid resistance (14 cases). No difference was found between the steroid responsive and resistant group with regard to age, BUN, serum creatinine, albumin, cholesterol, and urinary protein. The levels of U beta2- MG (microgram/g creatinine) were 250808+/-478917 and 1648+/-2386 in resistan ia Kwang-Yul Chang, et al.:Prediction of Steroid Responsiveness in Adult Minimal Change Nephrotic. Syndrome Using Urinary beta2-Microglobulint group and responsive group, respectively (P<0.05). The cut off value was 400microgram/ g creatinine with 78% of sensitivity and 48% of specificity. The likelihood ratio for the resistance was 2.5 to 2.8 with the U beta2-MG levels over 400 ug/g creatinine and was 0.2 to 0.3 below that value. Multivariate analysis confirmed that higher U beta2- MG level was associated with a lower likelihood of steroid responsiveness, independent of age, sex, creatinine, serum protein, and urinary protein. This study showed that the pretreatment U beta2- MG level may be used to identify subgroup of patients with MCNS who are more likely to be responsive to initial steroid treatment.