Risk stratification and long-term kidney survival in IgA nephropathy with particular emphasis on Oxford classification; A narrative review

Introduction: IgA nephropathy (IgAN) is one of the most common forms of glomerulonephritis worldwide. It leads to end-stage renal disease (ESRD) in many patients. At the time of diagnosis, risk stratification is of paramount importance in planning proper management in individual cases. Several studies have been conducted to determine the utility of various demographic, clinical, laboratory, and pathological features on renal biopsy to stratify the risk of disease progression and predict the likely outcome. This review summarizes the emerging data on demographic, clinical, laboratory, and histological prognosis along with risk factors associated with renal outcomes in patients with IgAN. Methods: For this review, we searched DOAJ (Directory of Open Access Journals), PubMed/Medline, Web of Science, Scopus, Embase, and Google Scholar, using keywords including; "IgA nephropathy," "IgA nephritis," "IgAN," "Berger’s disease," "Berger’s syndrome," "chronic glomerulonephritis, "prognostic factors," "risk factors," "risk stratification," "renal survival," "ESRD," "MEST classification," "MEST-C classification" and "Oxford Classification." To identify other relevant studies, we manually scanned the bibliographic lists of the identified studies and reviewed articles from January 2009 through December 2020. All relevant articles were carefully reviewed, and relevant information was extracted for this narrative review. Results: A total of 152 articles were retrieved from the above literature database searches. The abstracts were carefully reviewed to identify 35 articles containing information on prognostic factors and longterm renal survival in IgAN patients. Relevant information was collected and summarized for this review. The main focus was on using demographic, clinical, and laboratory features, especially serial changes in these parameters during follow-up, for this purpose. Recently a standardized, evidencebased formulation has been devised to evaluate and categorize pathological features on renal biopsy to augment and refine the risk stratification and prognostic value of traditional risk factors; it is popularly known as the Oxford classification of IgAN. There have been numerous validation studies in various ethnic groups that have proven its clinical utility. Conclusion: In conclusion, the clinicians should also take into account the pathologic variables according to the revised Oxford classification in addition to demographic, clinical, and laboratory parameters for early and reliable risk stratification and prognostication in individual patients at the time of diagnosis in IgAN for optimal management and ultimate improvement in long-term outcomes.