Comment on: Short and long-term outcomes of patients with pure membranous lupus nephritis compared to patients with proliferative disease: reply

Dear Editor, We thank Chen et al. for their thoughtful comments [1] and for engaging in constructive scientific dialogue regarding our recent study comparing outcomes in patients with pure membranous lupus nephritis (MLN) and proliferative lupus nephritis (PLN) [2]. Our work examined short-term renal responses as well as long-term renal and non-renal outcomes in a well-characterized cohort. Early treatment responses did not differ significantly between MLN and PLN, and although PLN had worse long-term outcomes, these differences were not statistically significant. Importantly, progression to end-stage kidney disease (ESKD) was associated with established clinical predictors rather than LN class. Thus, our study reinforces that MLN is not uniformly benign and warrants careful monitoring. Chen et al. expressed concern that our multivariable Cox models contained ‘up to 10’ variables, potentially risking overfitting [1]. We wish to clarify that this overstates the model complexity. The number of covariates varied by outcome, and each model included a parsimonious set of clinically justified predictors. We were attentive to aligning model complexity with the number of available events to support model stability and interpretability.