Interstitial fibrosis increases the risk of end-stage kidney disease in patients with lupus nephritis

Objective. To evaluate the risk of end-stage kidney disease (ESKD) in LN patients using tubulointerstitial lesion scores. Methods. Clinical profiles and histopathological presentations of 151 biopsy-proven LN patients were retrospectively examined. Risk factors of ESKD based on characteristics and scoring of their tubulointerstitial lesions [e.g. interstitial inflammation (II), tubular atrophy (TA) and interstitial fibrosis (IF)] were analysed. Results. The mean age of 151 LN patients was 36 years old, and 136 (90.1%) were female. The LN cases examined included: class I/II (n = 3, 2%), class III/IV (n = 119, 78.8%), class V (n = 23, 15.2%) and class VI (n = 6, 4.0%). The mean serum creatinine level was 1.4 mg/dl. Tubulointerstitial lesions were recorded in 120 (79.5%) patients. Prior to receiving renal biopsy, nine (6.0%) patients developed ESKD. During the follow-up period (mean, 58 months), an additional 47 patients (31.1%) progressed to ESKD. Multivariate analyses identified serum creatinine [hazard ratio (HR): 1.7, 95% CI: 1.42-2.03, P < 0.001] and IF (HR: 3.2, 95% CI: 1.58-6.49, P = 0.001) as independent risk factors of ESKD. Kaplan-Meier analysis further confirmed a heightened risk of ESKD associated with IF. Conclusion. Tubulointerstitial involvement is commonly observed in the histopathological presentation of LN. However, IF, rather than II or TA, was found to increase the risk of ESKD in our cohort. Therefore, to predict renal outcome in LN patients prior to adjusting immunosuppressive treatment, the degree of IF should be reviewed.