IgA nephropathy (IgAN) is the most common primary glomerulonephritis (GN) worldwide with higher rates in East and Pacific Asia compared to North America and Europe. Despite high reported prevalence of IgAN in these countries, the overall disease prevalence across Asia is not available. Treatment patterns of IgAN patients across Asian countries have also not been summarized. This literature review synthesized IgAN prevalence and treatment patterns among patients in Asian countries/regions, specifically Mainland China, Taiwan, and South Korea. A targeted literature review (TLR) was conducted in PubMed, Chinese (China National Knowledge Infrastructure, WANFANG) and Korean (Korean Medical Database, Korean Information Service System) databases for studies on IgAN prevalence and treatment patterns (e.g., percentage of patients using a given therapy, treatment adherence) from January 2010-May 2021. Grey literature searches using Google Scholar and Baidu (for China) were also conducted. This targeted review included 27 publications. IgAN prevalence is highly variable across Mainland China, Taiwan, and South Korea, with prevalence rates ranging from 6%-62%. In Mainland China, mean prevalence of IgAN is estimated at 25% among patients with renal biopsies (range: 6%-41%) and 38% (range: 30%-50%) among primary GN patients. In Taiwan, mean prevalence of IgAN is estimated at 12% (range: 11%-13%) among patients with renal biopsies and 26% among primary GN patients. In South Korea, mean prevalence of IgAN is estimated at 38% (range: 26%-62%) among patients with renal biopsies and 51.6% (range: 51.3%-51.9%) among primary GN patients. Country-specific treatment guidelines were identified for Mainland China only. Studies on real-world treatment patterns of IgAN were scarce in the study countries/regions. In Mainland China, only two pediatric and four adult IgAN patient studies were identified. No study reporting IgAN treatment patterns in Taiwan was identified. Three studies among adult IgAN patients in South Korea were identified. Among adult IgAN patients, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers (ACEI/ARBs) were the most common treatment ranging from 27.7%-90% in Mainland China and South Korea, followed by immunosuppressants (1.6%-85.5%) and steroids (10%-36.1%). ACEI/ARB and steroid use was also high among Chinese pediatric IgAN patients, ranging from 1.6%-45% across included studies. Approximately 6% of Chinese pediatric IgAN patients reported mycophenolate mofetil (MMF) use and 50% of patients underwent a tonsillectomy in one study sample. One study reported less optimal adherence with steroid treatment among Chinese IgAN patients, particularly among younger and female patients, due to concerns over side effects of steroid use. This TLR suggests variable IgAN prevalence in Mainland China, Taiwan, and South Korea. IgAN treatment primarily consisted of ACEI/ARBs, and high steroid use was found despite mixed evidence on its benefits and safety. There are also limited data on IgAN treatment patterns from Taiwan. Further research into IgAN epidemiology and treatment patterns at national levels across multiple Asian countries/regions is warranted to address gaps in evidence.
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