RESUMEN
Abstract Background: Nephritis occurs frequently in systemic lupus erythematosus (SLE) and may worsen disease morbidity and mortality. Knowing all characteristics of this manifestation helps to a prompt recognition and treatment. Aim: To compare the differences in clinical data, serological profile and treatment response of nephritis of early and late onset. Methods: Retrospective study of 71 SLE patients with biopsy proven nephritis divided in early nephritis group (diagnosis of nephritis in the first 5 years of the disease) and late nephritis (diagnosis of nephritis after 5 years). Epidemiological, serological, clinical and treatment data were collected from charts and compared. Results: In this sample, 70. 4% had early onset nephritis and 29.6% had late onset. No differences were noted in epidemiological, clinical, serological profile, SLICC and SLEDAI, except that late onset nephritis patients were older at nephritis diagnosis (p = 0.01). Regarding renal biopsy classification, C3 and C4 levels, serum creatinine, 24 h proteinuria and response rate to treatment the two groups were similar (p = NS). Patients with early onset had lower levels of hemoglobin at nephritis onset than those of late onset (p = 0.02). Conclusions: Most of SLE patients had nephritis in the first 5 years of disease. No major differences were noted when disease profile or treatment outcome of early and late onset nephritis were compared.(AU)