Supplementary Material for: Global Treatment Patterns for IgA Nephropathy in Adults: Results From a Real-World Survey

Introduction: Data on global treatment patterns for immunoglobulin A nephropathy (IgAN) are limited. Herein, we describe real-world treatment in patients with IgAN in clinical practice across distinct global regions. Methods: This was a retrospective analysis of data from a cross-sectional, survey-based study of nephrologists actively managing patients with IgAN (N = 174) and their patients receiving treatment (N = 869) in the United States, China, Japan, France, Germany, Italy, Spain, and the United Kingdom in 2021. Nephrologists completed patient record forms and patients completed voluntary patient self-completion forms. Outcomes included patient demographics, clinical characteristics, treatment patterns, and remaining unmet treatment needs. Results were reported using descriptive statistics. Results: At survey completion, mean (± standard deviation [SD]) patient age was 41.6 years (±13.7), and 57.4% were male. At diagnosis, median proteinuria was 1.8 g/day (range: 0.0–22.0), and mean (±SD) eGFR was 76.9 mL/min/1.73 m2 (±29.1). Median time from diagnosis to first IgAN treatment was 0.0 months (range: −12.8 to 111.4), and mean (±SD) number of treatment lines was 1.6 (±0.9). The most frequently prescribed treatments at survey completion were renin–angiotensin system inhibitors (RASi; 76.3%) and corticosteroids (42.8%). For treatments prescribed first, second, and third, RASi were received by 76.2% (n = 611/802), 79.7% (n = 247/310), and 86.0% (n = 98/114), and corticosteroids were received by 45.8% (n = 367/802), 45.2% (n = 140/310), and 57.9% (n = 66/114), respectively. At survey completion, 17.5% of nephrologists thought that patients’ prescribed treatment was not achieving the best possible disease control. High levels of proteinuria (≥1 g/day) were observed regardless of region or treatment line. Conclusion: This survey found that despite high levels of proteinuria among patients with IgAN, nephrologists generally adhered to conservative treatment approaches, in line with international guidelines at survey completion. These findings highlight an opportunity to improve patient outcomes and quality of life through the broader adoption of emerging treatments.