LESÕES VASCULARES RENAIS COMO FATORES PROGNÓSTICOS NA NEFRITE LÚPICA

Abstract

Introduction: Lupus nephritis (LN) is one of the leading causes of morbidity and mortality in systemic lupus erythematosus. Its diagnosis and prognosis, according to the ISN/RPS classification, are primarily based on glomerular and tubulointerstitial findings, which do not fully capture the disease's pathophysiology. In this context, renal vascular lesions (RVLs) have increasingly been studied as important determinants of poor renal outcomes in LN, yet remain underreported in the Brazilian population. Methods: This was a multicenter retrospective cohort study including 440 patients with biopsyproven LN (2014–2024), stratified into groups with and without RVLs. The RVLs were categorized into arterial sclerosis (AS), thrombotic microangiopathy (TMA), non-inflammatory lupus vasculopathy (NILV), and true renal vasculitis (TRV). A generalized linear model was used to assess the association between RVLs and estimated glomerular filtration rate (eGFR) at the time of biopsy. In a second phase, 212 patients were followed for two years, and differences in eGFR between groups were analyzed using a linear mixed model. In both analyses, models were adjusted for confounding variables based on a theoretical causal framework defined by a Directed Acyclic Graph (DAG). Results: At the time of renal biopsy, patients with AS and TMA were more frequently hypertensive and exhibited lower eGFR, higher chronicity index, and greater interstitial fibrosis/tubular atrophy. The presence of TMA was also associated with a higher need for acute dialysis. In adjusted models, AS, TMA, and NILV remained independently associated with lower eGFR (mean reductions of 15.4, 24.2, and 18.5 mL/min/1.73 m², respectively; p < 0.05). During follow-up, patients without vascular lesions had consistently higher and progressively improving eGFR over 24 months. TMA was associated with lower baseline eGFR followed by partial recovery, while AS was associated with persistently reduced eGFR. Both TMA and AS emerged as independent risk factors for impaired eGFR recovery after treatment. Conclusion: In the Brazilian population, AS, TMA, and NILV are markers of renal dysfunction in LN. These findings underscore the prognostic relevance of renal vascular lesions in patients with LN.