Little is known about the worldwide variation in incidence of primary glomerulonephritis (GN). The objective of this review was to critically appraise studies of incidence published in 1980-2010 so that an overall view of trends of these diseases can be found. This would provide important information for determining changes in rates and understanding variations between countries. All relevant papers found through searches of Medline, Embase and ScienceDirect were critically appraised and an assessment was made of the reliability of the reported incidence data. This review includes 40 studies of incidence of primary GN from Europe, North and South America, Canada, Australasia and the Middle East. Rates for the individual types of disease were found to be in adults, 0.2/100,000/year for membrano-proliferative GN, 0.2/100,000/year for mesangio-proliferative GN, 0.6/100,000/year for minimal change disease, 0.8/100,000/year for focal segmental glomerulosclerosis, 1.2/100,000/year for membranous nephropathy and 2.5/100,000/year for IgA nephropathy. Rates were lower in children at around 0.1/100,000/year with the exception of minimal change disease where incidence was reported to be 2.0/100,000/year in Caucasian children with higher rates in Arabian children (9.2/100,000/year) and Asian children (6.2-15.6/100,000/year). This study found that incidence rates of primary GN vary between 0.2/100,000/year and 2.5/100,000/year. The incidence of IgA nephropathy is at least 2.5/100,000/year in adults; this disease can exist subclinically and is therefore only detected by chance in some patients. In addition, referral policies for diagnostic biopsy vary between countries. This will affect the incidence rates found.
