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.

引言：目前关于免疫球蛋白A肾病（immunoglobulin A nephropathy，IgAN）的全球治疗模式数据较为匮乏。本研究旨在阐述全球不同地区临床实践中IgAN患者的真实世界治疗情况。

方法：本研究为回顾性分析，数据来源于2021年一项针对肾病专科医师的横断面调查研究，共纳入美国、中国、日本、法国、德国、意大利、西班牙及英国的174名活跃管理IgAN患者的专科医师，及其对应的869名接受治疗的IgAN患者。肾病专科医师填写患者记录表，患者填写自愿提交的自我调查表。研究结局指标包括患者人口学特征、临床特征、治疗模式及未被满足的治疗需求。结果采用描述性统计学方法进行报告。

结果：调查完成时，患者的平均年龄（±标准差[SD]）为41.6岁（±13.7），其中男性占比57.4%。确诊时，患者的蛋白尿中位数为1.8 g/日（范围：0.0~22.0 g/日），平均估算肾小球滤过率（estimated glomerular filtration rate，eGFR）为76.9 mL/min/1.73 m²（±29.1）。从确诊至首次接受IgAN治疗的中位时间为0.0个月（范围：-12.8~111.4个月），平均治疗线数为1.6（±0.9）。调查完成时最常开具的治疗方案为肾素-血管紧张素系统抑制剂（renin-angiotensin system inhibitors，RASi，占比76.3%）与糖皮质激素（占比42.8%）。就一线、二线、三线治疗而言，分别有76.2%（n=611/802）、79.7%（n=247/310）及86.0%（n=98/114）的患者接受了RASi治疗，分别有45.8%（n=367/802）、45.2%（n=140/310）及57.9%（n=66/114）的患者接受了糖皮质激素治疗。调查完成时，17.5%的肾病专科医师认为为患者开具的处方治疗未能实现最佳疾病控制。无论所处地区或治疗线数如何，均观察到存在高水平蛋白尿（≥1 g/日）的患者。

结论：本调查发现，尽管IgAN患者普遍存在高水平蛋白尿，但肾病专科医师总体遵循保守治疗策略，这与调查完成时的国际指南要求相符。上述研究结果表明，通过更广泛地应用新兴治疗手段，有望改善患者的临床结局与生活质量。