Nationwide renal biopsy data in Lithuania 1994-2012

Our aim was to evaluate the incidence of biopsy-proven kidney diseases in Lithuania and to compare their changes in three different time intervals. All Lithuanian kidney biopsies were performed in the National Center of Pathology, enabling analysis at the national level. The native kidney biopsy data were reviewed, and incidence of renal disorders and patient demographics were compared during three time intervals: 1994-1999, 2000-2006, and 2007-2012. A total of 5,368 kidney biopsies were performed, including 3,640 native kidney and 1,728 kidney transplant biopsies; 59.5 % (2,165) of the native kidney biopsies were classified as primary glomerulopathies. The most common entity was IgA nephropathy (737; 34.0 %), followed by focal segmental glomerulosclerosis (285; 13.2 %) and membranoproliferative glomerulonephritis (256; 11.8 %). Prominent decrease in incidence of membranoproliferative glomerulonephritis (16.8 to 8.7 % from the first to third time interval) and increase in (mainly, pauci-immune) crescentic glomerulonephritis (6.2 to 15.3 %) were noted over the study period. In a subgroup of 427 pediatric native kidney biopsies, IgAN accounted for 24.9 % of biopsies. The incidence of MCNS increased dramatically from the first to third time interval (6.3 to 25.4 %), while the number of MPGN increased in the second time interval (from 7.2 to 8.9 %) but decreased in the third one (to 4.4 %). Decrease in relative incidence of membranoproliferative glomerulonephritis, most likely, reflects improvement in socioeconomic conditions, while relative increase in crescentic glomerulonephritis is interpreted as improved diagnostics of the disease.