An overview on frequency of renal biopsy diagnosis in Brazil: clinical and pathological patterns based on 9,617 native kidney biopsies.

BACKGROUND Studies about the prevalence of renal and particularly glomerular diseases in Brazil are still scarce. METHODS We evaluated retrospectively the reports of 9,617 renal biopsies, analyzed by the same pathologist, from January 1993 to December 2007. RESULTS The 9,617 renal biopsies performed in subjects of all ages in native kidneys. 4,619 were primary glomerulopathies (GN), the most frequent was focal segmental glomerulosclerosis (FSGS, 24.6%), followed by membranous nephropathy (MN, 20.7%), IgA nephropathy (IgAN, 20.1%), minimal change disease (MCD, 15.5%), mesangioproliferative non IgAN (nonIgAN, 5.2%), diffuse proliferative GN (DPGN, 4.7%) and membranoproliferative GN (MPGN, 4.2%). Lupus nephritis was responsible for most cases which etiology was determined, i.e., 950 out of 2,046 cases (45.5%), followed by post infectious GN (18.9%), diabetic nephropathy (8.5%), benign and malignant nephroangiosclerosis (7.3%), haemolytic-uraemic syndrome and thrombotic thrombocytopenic purpura (HUS/TTP), amyloidosis (4.8%) and vasculitis (4.7%). There was a predominance of secondary GN in the North, mostly due to lupus nephritis (LN); FSGS was very common in Northeast (27.7%), Central (26.9%) and Southeast regions (24.1%); IgAN was most frequent in South (22.8%) and MN in North (29.6%); the total prevalence of MPGN was low, and its regional distribution has not changed along the years. CONCLUSION FSGS was the most frequent primary glomerular disease, followed closely by MN and IgAN. The predominance of FSGS is in accordance with recent studies all over the world that revealed its frequency is increasing. Lupus nephritis predominated among secondary GN in most regions, a finding observed in other studies.