Patients with childhood-onset systemic lupus erythematosus (cSLE) may have higher rates of lupus nephritis (LN), which is most likely to occur within the first 2 years of SLE diagnosis, according to study findings published in Lupus. Results also suggested that Black patients with cSLE may have worse short-term renal outcomes.
The prevalence of lupus nephritis is more often noted in children than adults and the epidemiology and management of cSLE has necessitated the reassessment of expected treatment outcomes.
Researchers used data from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) registry to identify traditional principles with regard to the diagnosis, treatment, and surveillance of LN in childhood. The researchers also aimed to confirm the validity of these principles in a contemporary multicenter cohort.
A total of 677 patients with cSLE (median age, 15 years; 83.2% adolescent girls) with an average disease duration of 1 year were included in the analysis. Of this cohort, 30.3% were White, 26.3% were Black, 11.8% were Asian, and the remaining patients identified as mixed race (4.4%), other race (3.8%), or had missing information (23.3%). The majority of patients identified as non-Hispanic (74.6%). Median follow-up was 9.3 months. A total of 50% of patients were followed-up with for at least 1 year; 12% of patients were followed-up with for at least 2 years.
Of the cohort, 216 (32%) patients were documented to have LN. No data were available for 2 patients. Of the 216 patients with LN, 93% were diagnosed with LN within 2 calendar years of cSLE diagnosis; 73.1% were diagnosed with LN in the same calendar year as that of the cSLE diagnosis. Including the 13.4% of patients who were diagnosed with LN in the calendar year following their cSLE diagnosis, 88.4% were diagnosed with LN within 1 calendar year of cSLE diagnosis.
Pure class 3 or I4 LN was reported among 64.8% of patients with LN; 10.2% had mixed class 3/4 or 4/5, and 13.9% has pure class 5 LN. Compared with patients who had proliferative LN, patients with membranous LN had proteinuria more commonly; however, it was not statistically significant (P =.71).
Compared with non-Black patients, Black patients with LN had worse renal outcomes and had a 4-fold increased rate for stage 3, 4, or 5 chronic kidney disease (CKD). There was no significant difference in remission achievement among patient groups (P =.11).
Of the 38 patients who had an estimated glomerular filtration (eGFR) rate of more than 60 mL/min/1.73 m3, 34.2% achieved remission. Among the 114 patients with an eGFR of more than 60 mL/min/1.73 m3, 4.4% progressed to stage 3 to 5 CKD.
Although rituximab was administered in 25.5% of patients with LN and 12% of patients with cSLE who did not have LN (P <.0001), there were no statistical differences in rituximab use based on patient LN status or other demographics including age, sex, race, or ethnicity.
“The current CARRA registry is a relatively new multicenter, diverse cohort,” the authors noted. “As it continues to enroll patients, further studies can be done to assess the short- and long-term outcomes of LN in cSLE.”
“Longitudinal data will allow for better understanding of therapeutic approaches and prognostic information,” they concluded.
Vazzana KM, Daga A, Goilav B, et al; for the CARRA Registry investigators. Principles of pediatric lupus nephritis in a prospective contemporary multi-center cohort. Lupus. Published online July 4, 2021. doi:10.1177/09612033211028658