Session Type: Abstract Submissions (ACR)
Background/Purpose: Lupus nephritis (LN) affects many patients with pediatric systemic lupus erythematosus (pSLE) and is a significant cause of disease morbidity. Inability to achieve remission of LN is associated with worse outcomes. Data from studies of adult patients with combined proliferative plus membranous LN (P/MLN) suggests that this combined subtype may be more refractory to current treatment strategies than isolated proliferative LN (PLN). The possibility that P/MLN may represent a more difficult to treat subtype in the pediatric population has not yet been examined. We aim to assess whether remission occurs less frequently in pediatric P/MLN, compared to pediatric PLN.
Methods: CARRA Registry data was obtained for 320 subjects with pSLE (age at onset <18 years) and LN; LN was diagnosed by renal biopsy and categorized according to ISN/RPS classification criteria. Remission of proteinuria was defined as protein/creatinine ratio < 0.5. Remission of hematuria was defined as < 6 RBC/hpf on urinalysis. These cutoffs were determined by the available clinical data from the CARRA registry. Remission was assessed at the most recent CARRA registry visit gathered ≥ 6 months after diagnostic kidney biopsy. Medication exposure data, non-renal disease characteristics, and demographic data were also assessed. Comparison of these data between subjects with P/MLN and subjects with PLN was conducted.
Results: A total 184 subjects had PLN (class III or class IV) and a total of 38 subjects had M/PLN (class III+V or class IV+V). No significant difference in proportion of subjects with remission in either proteinuria or hematuria was found between groups with and without membranous disease. (See Table). Estimated GFR less than 90 ml/min/1.73m2, indicating renal insufficiency, was found in 6.1 and 16.1% of subjects with PLN and P/MLN respectively, approaching statistical significance (p=0.07). Exposure rates to mycophenolate, cyclophosphamide, and rituximab were similar between groups. Patients in PLN and M/PLN groups were similar with respect to SLEDAI scores at last study visit, age of SLE onset, gender distribution, and ANA positivity. Subjects with class IV+V were significantly older at first renal biopsy compared to subjects with class IV (mean age 14.83 vs. 12.71, p=0.005), although this trend was not significant for comparison of subjects with class III vs. class III+V.
Conclusion: CARRA registry subjects with P/MLN and PLN have similar rates of remission for hematuria and proteinuria assessed at the last CARRA registry visit. There was a trend for the P/MLN group to have more renal insufficiency. This study was limited by its cross-sectional, retrospective design, and future longitudinal prospective studies will be useful in further assessing the relationship between renal histology findings and response of pediatric LN to treatment.
N. T. Ilowite,
T. CARRA Registry Investigators,
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ACR Meeting Abstracts - http://acrabstracts.org/abstract/comparison-of-remission-rates-for-pediatric-membranous-plus-proliferative-lupus-nephritis-versus-isolated-proliferative-lupus-nephritis-an-analysis-of-the-childhood-arthritis-and-rheumatism-research/