Clinical manifestations, prognosis, and treat-to-target assessment of pediatric lupus nephritis

Background Pediatric lupus nephritis (pLN) is one of the most refractory secondary kidney diseases in childhood. The treat-to-target (T2T) strategy has become the standard treatment for systemic lupus erythematosus (SLE). This study reviewed clinical features, overall remission status, and factors affecting prognosis, to guide pLN management according to T2T strategy. Methods This single-center retrospective study studied 220 children diagnosed with LN from January 2012 to December 2018, with > 6-month follow-up data on 173 and complete data on 137 patients. Primary outcome was treatment failure (deterioration or no response) at the latest follow-up. Results The most common pLN manifestation was proteinuria (81.36%). Females presented more often with rash (P<0.001) and alopecia (P=0.026) than males. Class IV LN (33.33%) was the most common grade on kidney biopsy. Median follow-up was 27.20 months (IQR, 15.78-44.45 months). One-, 3-, and 5-year cumulative overall survival rates were 93.5%, 87.8%, and 86.5%, respectively. The 5-year cumulative kidney survival rate was 97.1%. Regarding initial therapy, efficacy of corticosteroids combined with immunosuppressive agents was significantly better than corticosteroids alone (P=0.010). Factors with P<0.05 in univariate analysis, including hypoalbuminemia, higher SCr at diagnosis, lower eGFR at diagnosis, anti-dsDNA positivity, heavy proteinuria, hypertension, nervous-system involvement, treatment non-compliance, and SLEDAI-2K score, were used for logistic regression analysis. Logistic regression analysis showed hypertension (OR=0.845, P=0.011), nervous-system involvement (OR=4.240, P=0.005), treatment non-compliance (OR=6.433, P=0.001), and lower estimated glomerular filtration rate at diagnosis (OR=1.020, P=0.021) affected prognosis. At end of follow-up, 34.31% achieved varying levels of remission, and 8.76% were in low disease activity state (LDAS). Conclusions pLN usually presented with proteinuria, and class IV LN was the dominant pathology. Hypertension, nervous-system involvement, treatment non-compliance, and lower eGFR at diagnosis were independent risk factors for poor prognosis of kidney outcomes. Compared with renal remission rate and cumulative overall survival rate, the proportion of targets achieved was not ideal, suggesting T2T strategy should be used to guide pLN management.