Crescentic Glomerulonephritis: A Single Center Observational Cohort Study

Background The spectrum and outcomes of crescentic glomerulonephritis in South Asia is vastly different from that reported worldwide and there is a paucity of information. Methods It was an observational cohort study of renal biopsies done in the largest tertiary center in South India over a period of 10 years with ≥50percentage crescents on histology. Results A total of 8645 kidney biopsies were done at our center from January 2006 to December 2015, and 200 were crescentic glomerulonephritis. Patients were categorized into three etiological groups- anti-GBM (type I), immune complex (type II) and pauci-immune (type III). The most common was type II (96, 46.5percentage), followed by type III (73, 38percentage) and then type I (31, 15.5percentage). Female preponderance was seen across all three types. About half of all the three types presented with recent onset hypertension. Type II had the highest median proteinuria (4.2 (2.1-6) g/day, p=0.06) and the median eGFR was lowest in type I (5 (4-8) ml/min/1.73m2, p<0.001). Among type III, ANCA associated vasculitis (AAV) was seen only in about half of the patients. Nearly one third patients with type I was also positive for ANCA making them double positive. Severe glomerular insults like tuft necrosis and chronicity as evidenced by moderate to severe interstitial fibrosis was a predominant feature of type I. Conclusions ANCA negative vasculitis as well as double positive types are reported for the first time from South-Asia. Prevalence of ANCA negative vasculitis (type III subgroup) was much higher in our population. Renal survival was significantly worse in type I and III compared to type II. Types I or III, moderate to severe IFTA, presence of oliguria or anuria and increasing percentage of crescents in renal biopsy were significant predictors of dialysis dependence at index visit or of end stage kidney disease at follow-up in our cohort.