IgA nephropathy: clinical course characteristics and prognosis

IgA nephropathy (IgAN), first described in 1968, is the most common primary glomerulonephritis worldwide. The prevalence of the disease is highest in Asia compared with Europe and North America, with the possible underdiagnosis in regions such as Africa.

Typically, debuting in young patients, IgAN is one of the major causes of the development of end-stage chronic kidney disease, which requires the use of renal replacement therapy. However, recent studies have shown a rising incidence among older individuals, often with more severe outcomes.

The time course and prognosis of IgAN remain difficult to predict due to the pronounced polymorphism of clinical manifestations and morphological features, apparently reflecting a wide range of possible etiopathogenesis mechanisms. This literature review discusses current approaches to evaluating clinical symptoms and biomarkers in relation to pathomorphological features and disease prognosis. Traditionally, severe proteinuria has been regarded as the only reliable predictor of poor outcomes and the main indication for active treatment. However, recently evidence highlights the prognostic significance of proteinuria of any level, including persistent microhematuria, suggesting the need to reconsider current therapeutic paradigm. Two long-standing debates over the prognostic role of macrohematuria also remain unresolves. In addition, the review addresses the prognostic value of nephrotic syndrome depending on specific histological patterns, such as IgAN with minimal change disease or endocapillary proliferation. Based on published data, clinical variants of IgAN and their associations with disease outcomes are analyzed. The first results of cluster analysis, which have identified distinct disease phenotypes with differing risks of progression and treatment response, are also presented.

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