Crescentic Glomerulonephritis: What’s different in South Asia? - A Single Center Observational Cohort Study

ABSTRACT 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 ≥50% crescents on histology. Results A total of 8645 kidney biopsies were done at our center from January 2006 to December 2015, and 200 (2.31%) 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, 46.5%), followed by type III (73, 38%) and then type I (31, 15.5%). 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/1.73m 2 , 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 & III compared to type II. Types I/III, moderate to severe IFTA, presence of oliguria/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.