Frequency of renal pathology in Spain 1994-1999

Background. There are not enough large epidemiological population-based studies of biopsy-proven nephropathies with detailed clinical and histopathological data. Methods. The Glomerulonephritis Registry of the Spanish Society of Nephrology has obtained data from 7016 patients with biopsied renal diseases between 1994 and 1999, investigating prevalence, incidence and clinical and histopathological data. Biopsies of transplant kidneys have not been considered. Results. The observed biopsy rate for all ages is 4.8 per 100000 inhabitants. A male predominance is seen for all age groups. The most common clinical syndrome at any age is nephrotic syndrome. The prevalence of hypertension is higher in adults and elderly patients. The most common pathologies are IgA nephropathy, focal glomerulosclerosis, membranous nephropathy and lupus nephritis. The mean annual incidence (per million of population) of the most common nephropathies is IgA nephropathy 7.9, focal segmental glomerulosclerosis 6.4, membranous nephropathy 6.2, lupus nephritis 5.6, minimal-change disease 4.8, nephroangiosclerosis 4.6, vasculitis 4.3, membranoproliferative glomerulonephritis 3.6 and amyloidosis 3.3. In children, the most frequent causes are minimal-change disease, IgA nephropathy and focal glomerulosclerosis. In adults, the most common diagnoses are IgA nephropathy, lupus nephritis, and focal glomerulosclerosis. In elderly patients, the most frequently reported pathologies are vasculitis, membranous nephropathy and amyloidosis. Membranous nephropathy has increased in incidence in recent years. Conclusions. We provide representative population-based descriptive data on native biopsy-proven renal diseases in Spain.