Worse long-term renal outcome of lupus nephritis patients of African descent living in Europe

INTRODUCTION: Prognosis of lupus nephritis (LN) among patients of African descent living in Europe has been understudied. METHODS: In a retrospective study performed in two European university hospitals, we compared the prognosis of LN in patients of African descent or Caucasians. Remission was defined as a urine protein to creatinine (uP/C) ratio<0.5 g/g and a serum creatinine value<120% of baseline. Renal relapse was defined as the reappearance of a uP/C>1 g/g, leading to a repeat kidney biopsy and/or immunosuppressive treatment change. Chronic kidney disease (CKD) was defined as estimated glomerular filtration rate≤60 mL/min/1.73 m(2). Adherence was retrospectively assessed through medical files and/or hydroxychloroquine level measurements. RESULTS: 52 patients of African descent and 85 Caucasian patients were included in this analysis. Class III and isolated class V LN were more common among patients of African descent. Time to first renal remission did not differ between ethnic subgroups. By contrast, patients of African descent suffered from earlier renal flares, CKD was more common and time to CKD was shorter after a flare. In a multivariate analysis, African ancestry was an independent risk factor for progression to CKD. We observed no significant difference in non-adherence to treatment between the two groups. CONCLUSION: LN patients of African descent have worse renal outcomes, mainly explained by a higher rate of renal flare.