P0438PREDICTORS OF TREATMENT RESPONSE AND LONG-TERM OUTCOME IN PATIENTS WITH PAUCI-IMMUNE GLOMERULONEPHRITIS AND SEVERE RENAL DYSFUNCTION AT DIAGNOSIS

Abstract

Abstract Background and Aims Severe kidney involvement represents a frequent clinical scenario for patients with pauci-immune (PI) vasculitis. We aimed to explore the factors, which are associated with prognosis, in short and long term, following administration of appropriate immunosuppressive therapy. Method Patients were included if they had biopsy proven PI glomerulonephritis (GN) with estimated GFR<20 ml/min/1.73 m2 or dialysis requirement at presentation, received standard immunosuppression and were followed for a minimum period of one year. We recorded clinical, laboratory and histopathological parameters at diagnosis, at 3 months, at 1 year and at the end of follow up. Outcomes of interest included response to treatment, end stage kidney disease (ESKD), and death. Treatment response was defined by the ability to come off dialysis with an eGFR>20 ml/min/1.73 m2 with no signs of vasculitis. Histopathological evaluation included arteriosclerosis, % of normal glomeruli, activity index, chronicity index. Results A total of 83 patients, with a mean age of 59.6 (15.05) years were included. There were, 45 males (54.2%). After 3 months, 59 patients (71.1%) had responded to immunosuppressive therapy, 16 (19.3%) were dialysis depended, 5(6.02%) died and 2 were lost in follow up. By the end of the 1st year, 59 patients (71.1%) achieved remission, 16(19.3%) ended up in ESKD and 6(7.4%) died. Factors which were associated with treatment response included MPO-ANCA positivity [odds ratio OR:3.9, 95%CI (1.13-13.37) p=0.03], eGFR>10ml/min/1.73m2 at presentation [OR:2.5, 95% CI(0.86-7.30), p=0.009], normal glomeruli >10% [OR:3.8, 95%CI (1.24-12.1), p=0.02], and chronicity index more than 6 [OR:6.2, 95% CI(1.77-22.4), p=0.004]. Risk factors associated with ESKD included non-response to immunosuppressive therapy [Relative Risk RR:0.05, 95%CI (0.01-0.2) p<0.0001)], normal glomeruli<10% in the diagnostic biopsy [RR: 2.9, 95% CI (1.38-6.32), p=0.005] and age>75 years [RR:3.2, 95% CI (0.9-10.6) p=0.055]. Two of the 6 deaths were disease related. Conclusion A significant proportion of patients with PI-GN, who presented with severe renal dysfunction, responded to immunosuppressive therapy and recovered renal function approximately 3 months after initiation of therapy. The most important risk factors for ESKD were age>75 years, <10% normal glomeruli in the diagnostic kidney biopsy and non-response to immunosuppressive therapy.