#2954 A comparative view of IgA nephropathy care across four global regions
Authors: Dudzenski Christopher , Weiss Meghan 
Published: May 2024

Abstract

Background and Aims
IgA nephropathy (IgAN) is a chronic, rare, and slow progressing glomerular disease. IgAN treatment currently consists of angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB), sodium-glucose co-transporter 2 (SGLT2) inhibitors, corticosteroids, and recently approved Nefecon and sparsentan in select markets. This research compares approaches to IgAN treatment in four regions of the world.

Method
Data was collected in partnership with 730 nephrologists submitting chart data from 1,570 of their most recently seen IgAN patients to create a representative sample across the US, EU5 (UK, Germany, Italy, France, and Spain), Japan, and China via parallel online surveys in 2023.

Results
Regardless of their geographic location, audited patient charts revealed that hypertension, hyperlipidemia, obesity, and diabetes were the leading comorbid conditions among IgAN patients. Across the four regions evaluated, Japanese patients were the healthiest (44% have no comorbid conditions vs. 28% EU5, 25% China, 18% US) and Japanese nephrologists perceived 79% of their IgAN patients to be in “excellent” overall health. Comparatively, patients in the US had the highest calculated body mass index (28.2) and the most comorbid conditions reported. Audited records also revealed that patients in Japan and China were referred to nephrology care earlier in their CKD progression as measured by eGFR levels, with over 50% of patients referred to their current nephrologist in CKD Stages 1 or 2, compared to approximately 35% of patients in the US and EU5.
Chinese nephrologists (59%) and those in the US (53%) were most likely to agree that it is easy to identify IgAN patients who are likely to have rapid progression (vs. 43% EU5 and 40% Japan). When treating their IgAN patients, Japanese nephrologists ordered labs on a more frequent basis compared to those in the US, EU5, and China and on average, Japanese patients had blood work and urinalysis labs conducted six times within the past twelve months (versus four in the other countries.) Most audited patients had a calculated annual eGFR decline of 1 ml/year or more. Chinese patients (77%) were most notable for their IgAN progression, while those in Japan were least likely to be progressing in their disease (41%). Due to its chronic nature, most IgAN patients will eventually need dialysis, and while still representative of the majority of their audited patients, US nephrologists projected the lowest percentage of IgAN patients to eventually progress to end stage renal disease (66% vs. 73% Japan, 75% EU5, and 85% China).
Most participating nephrologists reported that they closely adhere to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines when treating their IgAN patients. Nearly all audited IgAN patients were on baseline therapy of ACE inhibitors or ARBs, while the uptake of SGLT2 inhibitors has been notable in China (44%), the US (43%), and EU5 (43%), with Japan (33%) trailing in current treatment rates. Meanwhile, the use of corticosteroid was also higher in patients in Japan (65%) and China (59%) compared to those in the EU5 (51%) and US (43%). Of note, tonsillectomies are frequently used as a treatment approach for IgAN patients in Japan, with 45% of patients having received the procedure, whereas this approach is used much less often in the other regions. Following a tonsillectomy, nearly all Japanese patients received a pulse of steroids, leading to higher overall corticosteroid use compared to other regions. At the time of fielding, Nefecon was available to prescribe in the US and Germany with 9% and 7% of patients currently on treatment, respectfully; however, sparsentan had not been approved in any regions.

Conclusion
The comparison of patient chart data across various regions reveals differences in perspectives and IgAN treatment approaches among nephrologists. Prognostic and predictive tools are available and utilized globally, but the reliability and correlation between results, lab values, and disease progression calls for better education and alignment of global treatment guidelines.