Clinicopathologic correlations of renal pathology in Spain

Background. There are not enough large epidemiologic population-based studies of biopsy-proven nephropathies with detailed clinicopathologic correlations. Methods. The Glomerulonephritis Registry of the Spanish Society of Nephrology has obtained data from 9378 cases with native biopsy-proven renal diseases and well-known clinical syndrome between 1994 and 2001, investigating clinicopathologic correlations. Patients were divided in three groups according to age: children (<15 years old), adults (15 to 65 years), and elderly (>65 years). Results. The most common clinical syndrome at any age is nephrotic syndrome (35.5%), followed by asymptomatic urinary abnormalities (25.9%), acute renal failure (12.9%), chronic renal failure (12.1%), nephritic syndrome (4.5%), macroscopic haematuria (4.5%), and arterial hypertension (3.0%). A male predominance is observed at any age (3:2). The frequencies of histologic findings are statistically different in all syndromes according to age. Minimal change disease is the most frequent finding in children with nephrotic syndrome (39.5%), whereas in adults and elderly, membranous nephropathy is the most prevalent (24.2% and 28.0%, respectively). Ig A nephropathy (IgAN) is the most frequent glomerulonephritis in patients with asymptomatic urinary abnormalities at any age. Acute renal failure is an important cause for performing a kidney biopsy in elderly and vasculitis is the main histologic finding. The clinical manifestations of focal segmental glomerulosclerosis, non-IgA mesangial nephropathy, lupus nephritis, vasculitis, and nephroangiosclerosis are statistically different according to age. Conclusion. The findings of clinicopathologic correlations obtained from the Spanish Registry of Glomerulonephritis on native biopsy-proven renal diseases add valuable information to previous reports and it can be the initial step for follow-up and prospective studies.