Primary renal disease in young adults with renal failure.

BACKGROUND No specific data have been published on primary renal disease (PRD) in young adults with end-stage renal failure (ESRF). For children, congenital abnormalities of the kidney and urinary tract (CAKUT) account for 50% of renal failure and other congenital and familial disease comprise 20%. This remains true for teenage children in paediatric registries. METHODS To investigate the causes of ESRF in young adults, the UK Renal Registry data for the period 2000-2006 have been reviewed and PRD reported for all aged 18-39 years. For comparison, US Renal Data System (USRDS) results are available for age groups 0-19, 20-29 and 30-39 years. These data are also compared with data reported by the British Association of Paediatric Nephrology (BAPN). RESULTS For the UK, there is a rise in the rate of 'aetiology uncertain' from 6% at 12-15 years to 21% by 18-21 years. This figure of 21% remains constant for the older patients in their third and fourth decades and can be increased by at least 5% by adding 'glomerulonephritis; histologically examined but unspecified'; but these figures compare with unknown rates of 36% for the US age group 20-29 years. In the UK, for those 18-21 years, 'glomerulonephritis' accounts for 28%, when 'Alport's disease' (6.5%) and 'unspecified' (4.5%) are excluded, which compares with age 12-15 of 26%. At age 18-21 years in the UK, there is a sharp decline in all CAKUT (26%) when compared with the BAPN incidence for the 12-15 age group of 45%. For those in their third decade, diabetes accounts for 14-18% of diagnoses, distorting our ability to compare data by percentage. CONCLUSIONS These young adult data in the UK are consistent with the hypothesis that many of the undiagnosed cases must be CAKUT or tubular disease.