P0426HISTOLOGICAL PREDICTORS OF RENAL PROGNOSIS IN LUPUS NEPHRITIS: WHICH COMPARTMENT MAKES THE DIFFERENCE?

Abstract

Abstract Background and Aims Lupus nephritis (LN) encompasses a spectrum of glomerular, tubulointerstitial, and vascular lesions; we aimed to evaluate which compartment injury has renal prognostic value. Method We retrospectively examined the renal outcome at 31 December 2015 of 66 patients (age 36 [28-52] years; 76% female; eGFR at baseline 60.8 [24.4-78.1] mL/min) who were diagnosed with lupus nephritis by kidney biopsy during 2010-2015. Data regarding the clinical presentation, renal function, histology (presence/absence of lesions - Table 1; ISN/RPS classification) and treatment were retrieved from the electronic patients’ files. We used a composite endpoint in the survival analysis (Cox proportional hazard models, CPH): renal replacement therapy initiation, doubling of serum creatinine and death, whichever came first. Results Nephrotic syndrome was the most frequent form of presentation (42%), followed by nephritic (24%) and nephrotic-nephritic (15%). Most of the patients received immunosuppression treatment (97%, 70% cyclophosphamide regimen). Twenty-five patients (38%) reached the composite endpoint. They were older, male more often, had higher mean arterial pressure (MAP), lower serum albumin, decreased eGFR and higher proteinuria. Moreover, they were in class IV LN and had glomerulosclerosis more frequently. Median renal survival for the entire cohort was 4.4 (95%CI, 2.3-6.5) years. In the multivariatle CPH for the histological predictors, only ISN/RPS classification and tubular atrophy were associated with renal survival (Table 1). In a CPH that included clinical, histological and treatment variables, only lower eGFR (0.97 (95%CI, 0.95-0.99)), MAP (1.03 (95%CI, 1.00-1.06)) and tubular atrophy (4.52 (95%CI, 1.50-13.55)) remained as independent predictors of renal survival. Conclusion Tubular atrophy seems to be an important prognostic sign in LN; therefore, greater importance should be given to the tubulointerstitial compartment evaluation.