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

Abstract

Introduction: Lupus nephritis (LN) is one of the most common and serious manifestations of systemic lupus erythematosus (SLE) and is recognized as the strongest predictor of poor prognosis. This study aims to analyze demographic characteristics, clinicopathological correlations, and risk factors associated with renal outcomes in a long-term follow-up of patients with LN. Method: 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). Results: 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 followup. 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 univariate 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. Discussion: 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.