Background: The knowledge of the epidemiology of biopsied renal diseases provides useful information in clinical practice. There are several epidemiologic population-based studies of biopsy-proven nephropathies with detailed clinicopathologic correlations that could be different according to the country analyzed.
Objective: To identify the prevalence of primary and secondary glomerular diseases and to study the trend of the pattern changes of the glomerulopathy in Thailand.
Material and Method: A retrospective study of percutaneous renal biopsies during a 23-year period of 1982 to 2005 was performed. A total of 3,555 consecutive native kidney biopsies in adult patients between 12 and 84 years of age were analyzed for the prevalence and changes in the 5-year interval over the two decades.
Results: From the clinical trial of 3,275 patients, the ratio between primary and secondary glomerular diseases was 2:1 (2154:1121). The most common primary glomerular disease (2154 patients) were IgM nephropathy (n = 986, 45.8%) followed by IgA nephropathy (n = 386, 17.9%); membranous nephropathy (n = 341, 15.8%); diffuse endocapillary proliferative glomerulonephritis (n = 114, 5.3%) and diffuse crescentic glomerulonephritis (n = 71, 3.3%). Lupus nephritis was the most prevalent cause of secondary glomerulonephritis in the present study (n = 992, 88.5%). Examination of the 5-year interval along the study period revealed a significant increase in the prevalence of IgA nephropathy and diabetic nephropathy. Prevalence of focal and segmental glomerulosclerosis rose by five times over the last two decades in contrast to IgM nephropathy, which prevalence is decreasing.
Conclusion: There is high prevalence of IgM nephropathy, IgA nephropathy, and lupus nephritis in Thailand which is different from other countries. It could be due to various races and altered environments. The information obtained from these results is an important contribution for the understanding of the prevalence in renal diseases in Thailand. It can be used as the baseline data for making efficient research into the appropriate and beneficial way of management in the future.

Keywords: Glomerulonephritis, Native kidney, Pathology, Prevalence, Renal biopsy