Spectrum of biopsy-proven kidney diseases at a tertiary care centre in Northern India

The spectrum of biopsy-proven kidney diseases varies across geographic regions and is influenced by biopsy practices and referral patterns. In India, the absence of a national kidney biopsy registry limits the availability of epidemiological data. We analysed kidney biopsies performed over a 12-year period at a large tertiary care referral centre in Northern India to describe the demographic, clinical, and histopathological spectrum of kidney diseases. This retrospective, observational study included all native kidney biopsies performed between January 2013 and October 2024. Demographic characteristics, clinical indications, comorbidities, and histopathological diagnoses were retrieved from hospital records. Biopsies were evaluated using light microscopy (LM) and immunofluorescence (IF) in all cases, with electron microscopy (EM) performed selectively. Diagnoses were categorised into primary glomerular disease, secondary glomerular disease, tubulointerstitial disease, vascular disease, and advanced sclerosis. Data was analysed descriptively. A total of 1,664 kidney biopsies were included (mean age 41 ± 16.9 years; 64.4% male). Primary glomerular diseases were the most frequent diagnoses (63.6%), followed by secondary glomerular diseases (20.1%), tubulointerstitial diseases (10.2%), and vascular diseases (3.3%). Among primary glomerular diseases, IgA nephropathy (18.6%) was most common, followed by membranous nephropathy (12.1%) and minimal change disease (12.0%). Lupus nephritis (7.4%) and diabetic nephropathy (5.6%) were the most frequent secondary glomerular diseases. Nephrotic syndrome was the predominant clinical presentation in primary glomerular diseases, whereas renal dysfunction with proteinuria was more common in secondary glomerular diseases. Age-specific patterns were observed, with minimal change disease predominating in children, IgA nephropathy in young adults, membranous nephropathy in middle-aged adults, and pauci-immune glomerulonephritis in older patients. In this large hospital-based biopsy registry from Northern India, IgA nephropathy and membranous nephropathy were the most frequent biopsy-proven primary glomerular diseases, while lupus nephritis and diabetic nephropathy predominated among secondary glomerular diseases. Multicentre and national biopsy registries are required to better define the epidemiology of kidney diseases in India.