Background: The purpose of this retrospective study was to analyse patients from four centres in three continents to determine if differences in long-term outcome of IgA nephropathy (IgAN) are explained by clinical and laboratory features at presentation.
Methods: The study included 711 adults with biopsy-proven IgAN from Glasgow, UK (n = 112), Helsinki, Finland (n = 204), Sydney, Australia (n = 121) and Toronto, Canada (n = 274). Data collected from time of presentation to a nephrologist were age, gender, 24-h urine protein excretion (UP(0)), mean arterial pressure (MAP(0)) and creatinine clearance (CrCl(0)).