Chronic kidney disease trajectories in lupus nephritis: Is progression unavoidable?

To characterize trajectories of chronic kidney disease (CKD) in lupus nephritis (LN) and identify predictors of CKD progression.

At diagnosis, patients were classified as having impaired kidney function (IKF; eGFR <60 mL/min/1.73 m²,at diagnosis). At last follow-up, outcomes were defined as CKD (KDIGO stages 3-5), sustained complete renal response (CRR; eGFR >90 mL/min/1.73 m², proteinuria <150 mg/day, inactive urinary sediment for ≥3 years). Predictors of CKD were assessed using Cox regression analysis.

Among 260 patients, 77 (29.6%) had IKF. Over a median follow-up of 189 months (IQR 91.6-300.4), 13 (5%) died and 54 (20.7%) developed CKD. Of the remaining 206 patients, 74 (35.9%) achieved sustained CRR for a median of 110.5 months (IQR 66.7-190.7). CKD-free survival at 10 and 20 years was 76.2% and 63.7% in IKF patients versus 96.2% and 91.3% in those without IKF; corresponding rates were 93.5% and 82.4% in IKF patients who recovered eGFR ≥60 mL/min/1.73 m² at 1 year. Baseline IKF (HR:4.14; p = 0.001) and chronicity index (HR:1.20; p = 0.001) independently predicted CKD. When stratified by renal trajectory, patients with IKF who recovered kidney function at 1 year remained at higher risk than those with preserved baseline function (HR 3.23; p = 0.001), while chronicity index was no longer significant.

Over long-term follow-up, one in five LN patients developed CKD, and one-third were in sustained CRR. Baseline IKF identifies a high-risk but heterogeneous group. Early recovery improves prognosis but does not fully offset the long-term risk associated with initial renal impairment.