Early EULAR Target Achievement and Kidney Outcomes in Lupus Nephritis

The prognostic value of achieving the European Alliance of Associations for Rheumatology (EULAR) 3- and 6-month treatment targets in lupus nephritis (LN) remains uncertain.

We conducted a multicenter retrospective cohort study of adults with biopsy-proven proliferative LN. Patients were classified by EULAR target achievement: a ≥ 25% reduction in urine protein-to-creatinine ratio (UPCR) with preserved kidney function at 3 months and a ≥ 50% reduction in UPCR at 6 months. The primary outcome was a ≥ 30% decline in estimated glomerular filtration rate (eGFR) at 24 months from the higher of baseline or 3-month eGFR. Multivariable logistic regression and linear mixed-effects models were used.

Among 449 screened patients, 293 and 288 constituted the 3- and 6-month analytic cohorts, respectively. For the 3-month EULAR target analysis, the primary outcome occurred in 24/213 (11.3%) achievers and 18/80 (22.5%) nonachievers (adjusted odds ratio [OR], 0.40; 95% confidence interval [CI], 0.20-0.82). For the 6-month EULAR target analysis, the corresponding proportions were 31/246 (12.6%) and 11/42 (26.2%) (adjusted OR, 0.40; 95% CI, 0.17-0.91). Adjusted eGFR trajectories were higher in achievers, although separation preceded 6-month classification. In a 3-month landmark analysis, the composite target showed no clear incremental association beyond kidney function at 3 months, whereas the UPCR-reduction criterion remained associated with subsequent eGFR decline (OR, 0.34; 95% CI, 0.14-0.86).

Achievement of the EULAR early treatment targets at 3 and 6 months was associated with better kidney outcomes in proliferative LN. Achievement by 3 months may identify patients with a particularly favorable renal prognosis.