Treatment effectiveness and long-term prognosis of childhood-onset lupus nephritis

Abstract

Objectives: To analyze the clinical characteristics, treatment effectiveness and long-term prognosis of childhood-onset lupus nephritis (LN), and to explore the risk factors for progression to end-stage renal disease (ESRD). Methods: In this retrospective study, the clinical data including general conditions, clinical manifestations, laboratory examinations, treatment, following up (till December 31st, 2020) and prognosis of 343 children with LN who were treated and followed up in the First Affiliated Hospital of Sun Yat-sen University from January 1, 2003 to December 31, 2019 were analyzed. Complete remission rates were compared between different pathological types according to renal biopsies and flare rates were compared between complete remission group and partial remission group according to the treatment effectiveness after 6 months of induction treatment. To investigate the risk factors of ESRD, the prognosis of flare and non-flare cases, and of cases with normal and elevated serum creatinine levels at baseline, was compared. Chi-squared tests were used for comparison between groups, and cumulative survival rate and renal survival rates were calculated by Kaplan-Meier survival analysis. Risk factors for ESRD were analyzed by COX regression model. Results: Among the 343 children, 68 were males (19.8%) and 275 were females (80.2%) with a median age of 13.0 (11.0, 16.0) years. Regarding the renal symptoms, 305 (88.9%) children had proteinuria and 245 (71.4%) had hematuria; while for extra-renal manifestations, 273 (79.6%) had anemia, 183 (53.4%) had rashes and 165 (48.1%) had fever. A total of 212 (61.8%) children had severely active SLE at initial presentation. After 6 months of induction treatment, the complete remission rate was 63.8% (219/343) and the partial remission rate was 27.1% (93/343). The complete remission rate was significantly higher in type Ⅰ and type Ⅱ LN compared to type Ⅳ LN (10/12 vs. 82/135 (60.7%), χ²=3.936, P=0.047). One hundred and ten children who achieved remission, including complete remission and partial remission, experienced renal flare with a flare rate of 35.3% and a mean time to flare was (43.2±28.4) months. There was no significant difference in flare rates between complete and partial remission group (36.1% (79/219) vs. 33.3% (31/93), χ²=3.394, P=0.065). The follow-up time of all the children was 60.4 (32.3, 100.9) months. During the follow-up period, 15 children died and the cumulative survival rates at 3, 5 and 10 years were 97.2%, 96.4% and 93.3%, respectively; 14 children progressed to ESRD and the cumulative renal survival rates at 3, 5, and 10 years were 99.2%, 97.1%, and 93.4%, respectively. COX multivariate analysis demonstrated that elevated serum creatinine at baseline, nephritic flare and nephrotic flare were independent risk factors for progression of ESRD (hazard ratio (HR)=3.575, 21.550 and 8.590, 95%CI 1.127-11.341, 2.394-194.027 and 1.042-70.823, P=0.031, 0.006, and 0.046, respectively). Conclusions: Children with LN are characterized by high SLE disease activity and multi-system involvement at onset. After 6 months of induction treatment, most of LN children could achieve clinical remission but some would experience renal flare. Nephritic flare, nephrotic flare and elevated serum creatinine at onset are independent risk factors for the progression of ESRD in children with LN.