Occurrence of kidney diseases and patterns of glomerular disease based on a 10-year kidney biopsy material: a retrospective single-centre analysis in Estonia.

Objective: Kidney biopsy is an important diagnostic tool in assessing glomerular damage. This study aimed to determine the occurrence of glomerular disease during the past decade at a single centre, to assess potential changes in the structure of primary glomerulopathies over time, and to define gender- and age-related differences.

Material and methods: A total of 578 consecutive native kidney biopsies during the period 2000-2010 was retrospectively reviewed at Tartu University Hospital, Estonia. Biopsies were evaluated according to clinical data with standard histological methods.

Results: The patients' mean age was 39.9 ± 17.9 (range 4-87) years. Less than half of informative kidney biopsies (n = 547) comprised primary glomerulopathies (45.4%), the patients' mean age was 38.7 ± 17.7 (4-79) years and the predominant group comprised male patients. Secondary glomerulopathies made up 22.3%, tubulointerstitial diseases 8.2% and other conditions 24.1%. Among primary glomerulopathies, inflammatory damage to glomeruli dominated (63.4%), whereas immunoglobulin A (IgA) nephropathy was the most common disease (35.5%). Non-inflammatory diseases of glomeruli made up 34.6%, among which the most common was focal and segmental glomerulosclerosis (16.1%), followed by minimal change disease (14.1%). Membranoproliferative glomerulonephritis was a rare form of glomerular damage among primary glomerulopathies (7.7%). Comparison between male and female cases in the primary glomerulopathies group revealed a statistically significant difference in their frequency (p = 0.01).

Conclusions: Inflammatory glomerulopathies mostly prevailed in the spectrum of primary glomerulopathies. IgA nephropathy was the most common glomerulopathy. Comparing the data with those from a 15-year earlier period at the same centre, a change towards non-inflammatory glomerulopathies was noticed.