Thirty years of experience with anti-neutrophil cytoplasmic antibody glomerulonephritis in Charles Nicolle Hospital-Tunisia: a retrospective cohort study

INTRODUCTION: antineutrophil cytoplasmic antibodies (ANCA) associated Glomerulonephritis (GN) is rare but a life-threatening disease especially, particularly in patients with advanced renal failure at presentation. This study aims to evaluate the epidemiological, clinical and histopathological features of renal involvement and investigate factors associated with ESRD. METHODS: patients with renal biopsy-proven ANCA associated glomerulonephritis were included retrospectively over a thirty years period. The renal survival, defined as time to reach ESRD, was evaluated based on clinical parameters, histopathological classification as well as the renal risk score. RESULTS: a total of 65 patients with crescentic GN were included in the study. The mean age was 47.9 years ± 22.4 years (range: 18-78) with an M/F sex ratio at 1.13. Hematuria, proteinuria and oliguria were found in respectively 100%, 81.5% and 56.2% of cases. Sixty patients (92.3%) had renal failure at presentation, and 30 patients (46%) required initial hemodialysis (HD) therapy. The pattern of glomerular injury was categorized as mixed in 43.7% of cases, sclerotic in 34.3%, crescentic in 16.6%, and focal class in 6%. Regarding renal risk score, patients were classified in the category low risk, intermediate risk and high risk with respectively 16.9%, 44.6% and 38.4%. All patients received corticosteroids and immunosuppressive treatment. Complete, partial remission and relapses were noted in respectively 15.3%, 18% and 72% of cases. Factors associated with ESRD were serum creatinine level >500 μmol/l (P=0,0016), CRP level >60 mg/l (P = 0,0013), interstitial fibrosis (P=0,0009) and glomerulosclerosis> 10% of total glomeruli (P=0,001). The survival rate was 89%, 60.9% and 32.8% at respectively 1, 5 and 10 years. Death occurred in 10 cases (15%) caused mostly by infections (40%). Initial serum creatinine level>140 μmol/l (P=0,02), alveolar hemorrhage (P=0.001) and infections (P=0,0001) were associated with mortality. CONCLUSION: in our cohort of ANCA GN, confirms the data showing improved patient survival but constantly high relapse risk. In addition, we observed that ANCA GN classification was predictive, as the risk of progressing to ESRD increased with the ascending category of focal, crescentic, mixed and sclerotic GN.