Epidemiological, immunological, and treatment response profile of patients with lupus nephritis in Brazil.

Background and hypothesis: Brazil has the largest number of individuals of African descent outside Africa and a very admixed population. Among cases of lupus nephritis (LN) in the country, there are differences in incidence, and even in severity, depending on the location and characteristics of the population studied. The aim of this study was to describe the clinical and epidemiological characteristics of LN in Brazil, as well as to determine which of those characteristics would be risk factors for a poor renal prognosis.

Methods: This was a retrospective, descriptive observational study of patients diagnosed with LN who underwent kidney biopsy between 1999 and 2015 in the Nephrology Department of the Hospital das Clínicas, in São Paulo, Brazil. Data were collected from electronic medical records.

Results: We evaluated 398 patients, among who 94.1% and 77.7% tested positive for antinuclear antibodies and anti-DNA antibodies, respectively, whereas 33.7% showed the full-house pattern. The time from LN symptom onset to biopsy was <6 months in 47.5% (early biopsy group) and ≥6 months in 52.5% (late biopsy group). In the early biopsy group, the chronicity index was lower and the activity index was higher. Multivariate analysis showed that a higher chronicity index was the only independent risk factor for progression to requiring kidney replacement therapy.

Conclusion: Late biopsy seems to be associated with negative renal outcomes in LN. However, it seems that a higher chronicity index is the main predictor of a poor renal outcome among patients with LN in Brazil.