Clinical characteristics, disease flares, infections and their impact on kidney outcomes in pediatric lupus nephritis: A cohort study

Background Limited data exists on clinical predictors of kidney outcomes in children with lupus nephritis (LN). Methods Children aged below 18 years with biopsy-proven LN followed from January 2010 to February 2024 in a tertiary-care center were enrolled in order to characterize their clinical presentations, flares, infections, histology and determine Major Adverse Kidney Events (MAKE) (defined as eGFR < 60 mL/min/1.73 m2 and/or death). Data was analysed to identify predictive factors of adverse outcomes. Results Seventy-five children (20% boys) with median (IQR) age at diagnosis 11.2 (9,13) years, were studied. Clinical presentations were nephritic syndrome, mixed nephritic-nephrotic features, rapidly progressive glomerulonephritis (RPGN), and nephrotic syndrome in 24 (32%), 15 (20%), 11 (14.7%) and 5 (6.7%) patients, respectively. Proliferative LN was the major (70.6%) histological subtype. In total, 75 kidney flares (21.3% nephritic) with incidence rate (IR) of 0.48 flares per person-year were noted in 31 (41.3%) children. Infections occurred in 32 (42.6%), with IR of 0.58 episodes per person-year. Bacterial pneumonia 14 (22.9%), sepsis 10 (16.3%) and tropical infections 6 (9.8%) were most common. At median last follow-up of 2.3 (1.3, 5.6) years with 85.4% kidney-survival rate, 41 (54.6%), and 21 (28%) were in complete-response (CR), and partial-response (PR), respectively. Proliferative LN and those in PR or NR were at significantly higher risk of kidney flares and infections, regardless of initial induction therapy. RPGN at presentation, non-responders at 6 months and severe kidney flare ever predicted MAKE in 11 (14.6%) children. Conclusions Multiple kidney flares and infections constitute a significant morbidity in LN. RPGN, non-responders and severe kidney flare predict adverse kidney outcomes.