Impact of intrarenal arterial lesions on prognosis of IgA nephropathy: insights from a retrospective cohort study

IgA nephropathy (IgAN) presents a challenging spectrum of outcomes, often complicated by intrarenal arterial/arteriolar lesions (IALs) in affected individuals. Despite their clinical relevance, existing criteria for classifying and assessing the severity of these lesions remain undefined. This study aimed to establish semi-quantitative assessment criteria for grading IALs and to evaluate their prognostic significance in patients with IgAN. We conducted a retrospective cohort study of 417 cases of primary IgAN in which IALs were meticulously scored in individual biopsies. Kaplan–Meier survival analysis was employed to compare the time to the renal composite endpoint between different IALs severity groups. The association between the severity of IALs and clinical outcomes was further evaluated using multivariate Cox regression models to control for potential confounders. Among the 417 patients studied, 230 (55.2%) exhibited IALs. Kaplan-Meier curve analysis showed a higher cumulative incidence of the composite endpoint in patients with IALs (<i>p</i> &lt; 0.001). In a compelling multivariate analysis, we identified IALs and its subclassifications, including moderate to severe intimal fibrosis and hyalinosis, as strong independent risk factors for poor prognosis (IALs: HR = 2.15, <i>p</i> = 0.009; moderate to severe hyalinosis: HR = 3.58, <i>p</i> = 0.001; moderate to severe intimal fibrosis: HR = 3.56, <i>p</i> = 0.001). Our findings underscore the prognostic significance of IALs in IgAN, particularly moderate to severe intimal fibrosis and hyalinosis and highlight the urgent need for novel therapeutic strategies specifically designed to mitigate the impact of IALs in high-risk IgAN patients.