Renal outcomes in the long-term follow-up of lupus nephritis

Lupus nephritis (LN) is one of the most common and serious manifestations of systemic lupus erythe-matosus (SLE) and is recognized as the strongest predictor of poor prognosis. This study aims to analyze demographic characteristics, clinicopathological corre-lations, and risk factors associated with renal outcomes in a long-term follow-up of patients with LN.

This is a retrospective observational cohort study from 112 biopsy-proven LN patients, followed from July 1985 to August 2015. We have evaluated risk factors associated with renal impairment (doubling of serum creatinine), end-stage renal disease (ESRD, eGFR <15 mL/min) and cumulative renal damage using the Systemic Lupus International Collaborating Clinics/ACR Damage Index (SDI).

The median time of follow-up was 8.3 years. Class IV LN predominated (64.3%), alone or in combination. There was a statistically significant increase in the renal score of SDI between 5 and 10 years of follow-up. In the multivariate analysis, final SDI correlated with initial eGFR <75 mL/min (p < 0.001) and proteinuria >3.5 g/24 h during the course of the disease (p < 0.001), overcoming parameters identified in uni-variate analysis as using cyclophosphamide (p = 0.010) and not using antimalarials (p = 0.003); 13.4% of the patients progressed to renal function impairment, and 11.6% to ESRD.

Accumulated renal damage by SDI was a frequent finding. The main determinants of renal outcome were baseline eGFR <75 mL/min and proteinuria >3.5 g/24 h during follow-up. Thus, early diagnosis and better management of LN, especially in case of high levels of proteinuria, may help improve prognosis.