Comparative Effectiveness of Mycophenolate Mofetil for the Treatment of Juvenile‐Onset Proliferative Lupus Nephritis

OBJECTIVE: Although juvenile-onset proliferative lupus nephritis (PLN) leads to significant morbidity and mortality, there is no clinical trials-based evidence to support the treatment effectiveness of any therapy for juvenile-onset PLN. Marginal structural models enable us to estimate treatment effectiveness using observational data while accounting for confounding by indication. METHODS: We used prospectively collected data to examine the effect of mycophenolate mofetil (MMF), compared to the use of other therapies, on the long-term outcome of a juvenile-onset PLN cohort (age at PLN onset <18 years). The major outcome variable was the estimated glomerular filtration rate (GFR) using the revised Schwartz formula. Confounding by indication was corrected for marginal structural model. RESULTS: A total of 172 subjects with juvenile-onset PLN, with a mean followup duration of approximately 4 years, were included. Overall, MMF was superior to other therapies, with a relative effect estimate for MMF of 1.06, i.e., 6% better estimated GFR on average (95% confidence interval 0.7, 11.3), corrected for potential confounding by indication. We found that beginning in year 4 there was a significant improvement in estimated GFR in the patients who were treated with MMF versus other therapies. This improvement was maintained until the end of the study. CONCLUSION: MMF was more beneficial than other therapies in improving/maintaining long-term renal function in patients with juvenile-onset PLN up to a maximum followup of 7 years. This finding is consistent with evidence from adult PLN clinical trials.