Kidney biopsy findings in patients with obesity exhibit a wide spectrum of disease entities.

Background: Obesity is a growing public health concern and an independent contributor to chronic kidney disease, with obesity-related glomerulopathy (ORG) representing a distinct but insufficiently characterized entity. This study aimed to comprehensively describe the spectrum of kidney histological damage in patients with obesity and overt kidney disease. Methods: We reviewed 503 native kidney biopsies performed at Hospices Civils de Lyon between 2019 and 2022, identifying 103 adults with obesity. Glomerular histology was compared to 206 controls matched 2:1 for age, sex, hypertension, and diabetes. Results: In the cohort with obesity, mean body mass index (BMI) was 35.1 kg/m²; 83% had hypertension and 33% had diabetes. Biopsies were performed for active urinary sediment (56%), proteinuria (49%), and acute or chronic kidney failure (31% of cases each). The mean estimated glomerular filtration rate was 47 ml/min/1.73 m², and proteinuria was 3.13 g/day. The post-biopsy complication rate was similar between groups. A wide spectrum of renal lesions was observed: hypertensive nephrosclerosis (34%), acute tubular necrosis (34%), diabetic nephropathy (17%), IgA nephropathy (13%), and other glomerulonephritides. ORG was identified in 25.2% of cases, isolated in 6.8% and associated with other lesions in 18.4%, while 74.8% had alternative diagnoses. Although no significant difference in glomerular size was observed between patients with obesity and controls, glomerular diameter was positively correlated with BMI ( Conclusion: ORG is not the predominant cause of kidney disease in patients with obesity. Given the wide range of alternative diagnoses and the safety of the procedure, renal biopsy should be considered to guide accurate diagnosis and optimize management.