Renal involvement in ANCA–associated vasculitis (AAV) is associated with poor outcomes. The clinical significance of arteritis of the small kidney arteries has not been evaluated in detail.

In a multicenter cohort of patients with AAV and renal involvement, we sought to describe the clinicopathologic characteristics of patients with AAV who had renal arteritis at diagnosis, and to retrospectively analyze their prognostic value.

We included 251 patients diagnosed with AAV and renal involvement between 2000 and 2019, including 34 patients (13.5%) with arteritis. Patients with AAV-associated arteritis were older, and had a more pronounced inflammatory syndrome compared with patients without arteritis; they also had significantly lower renal survival (P=0.01). In multivariable analysis, the ANCA renal risk score, age at diagnosis, history of diabetes mellitus, and arteritis on index kidney biopsy were independently associated with ESKD. The addition of the arteritis status significantly improved the discrimination of the ANCA renal risk score, with a concordance index (C-index) of 0.77 for the ANCA renal risk score alone, versus a C-index of 0.80 for the ANCA renal risk score plus arteritis status (P=0.008); ESKD-free survival was significantly worse for patients with an arteritis involving small arteries who were classified as having low or moderate risk, according to the ANCA renal risk score. In two external validation cohorts, we confirmed the incidence and phenotype of this AAV subtype.

Our findings suggest AAV with renal arteritis represents a different subtype of AAV with specific clinical and histologic characteristics. The prognostic contribution of the arteritis status remains to be prospectively confirmed.

ANCA 相关性血管炎 (AAV) 的肾脏受累与不良预后相关。肾小动脉炎的临床意义尚未得到详细评估。

在 AAV 和肾脏受累患者的多中心队列中，我们试图描述诊断时患有肾动脉炎的 AAV 患者的临床病理学特征，并回顾性分析其预后价值。

我们纳入了 2000 年至 2019 年间诊断为 AAV 和肾脏受累的 251 名患者，其中 34 名 (13.5%) 患有动脉炎。与没有动脉炎的患者相比，AAV 相关性动脉炎患者年龄更大，炎症综合征更明显；他们的肾脏存活率也显着降低（P = 0.01）。在多变量分析中，ANCA 肾脏风险评分、诊断时的年龄、糖尿病病史和肾活检显示的动脉炎与 ESKD 独立相关。动脉炎状态的增加显着改善了 ANCA 肾脏风险评分的辨别力，仅 ANCA 肾脏风险评分的一致性指数（C 指数）为 0.77，而 ANCA 肾脏风险评分加上的 C 指数为 0.80动脉炎状态（P=0.008); 根据 ANCA 肾脏风险评分，患有累及小动脉的动脉炎患者的无 ESKD 生存率明显更差，这些患者被归类为低风险或中度风险。在两个外部验证队列中，我们确认了这种 AAV 亚型的发生率和表型。

我们的研究结果表明，伴有肾动脉炎的 AAV 代表了具有特定临床和组织学特征的 AAV 的不同亚型。动脉炎状态对预后的贡献仍有待前瞻性证实。