Abstract
Introduction: Podocyte injury has been proven to be a major cause for poor renal outcomes after acute kidney injury (AKI). However, clinical trial data are still limited. This study aimed to explore the clinical correlations between podocyte injury and renal outcomes in hospitalized AKI patients. Method: This retrospective study analyzed data on 52 AKI patients who were histologically diagnosed with acute tubular necrosis or acute interstitial nephritis from six centers throughout China between January 2012 and June 2023. Patients were classified into two groups based on the degree of foot process fusion: ≤50% (mild podocyte injury group) and >50% (severe podocyte injury group). The outcomes were post-AKI new-onset proteinuria and incident CKD. Results: Among 52 AKI patients (14 male; median age, 49 [30, 56] years), 28 (53.8%) had mild podocyte injury; 24 (46.2%) had severe podocyte injury. After 12-month follow-up, 16 (57.1%) had post-AKI new-onset proteinuria, and 5 (17.9%) had post-AKI incident CKD in mild podocyte injury group. Twenty (83.3%) had post-AKI new-onset proteinuria, and 14 (58.3%) had post-AKI incident CKD in severe podocyte injury group. Patients with more severe foot process fusion exhibited significantly higher incidences of post-AKI new-onset proteinuria (83.3% vs. 57.1%, p = 0.041) and incident CKD (58.3% vs. 17.9%, p = 0.003) at 12 months following AKI. The degree of foot process fusion (95% CI 1.013∼3.88, p = 0.048) and proteinuria at 3 months (95% CI 1.309∼5.443, p = 0.015) were identified as independent risk factors for post-AKI new-onset proteinuria at 12 months. The degree of foot process fusion (95% CI 1.026∼14.196, p = 0.048), and the presence of partial renal pathological features, including tubular atrophy (95% CI 1.012∼5.958, p = 0.030), interstitial inflammation (95% CI 1.005∼6.846, p = 0.039), interstitial fibrosis (95% CI 1.110∼6.075, p = 0.043) were independent risk factors for post-AKI incident CKD at 12 months. Kaplan-Meier analysis shows severe podocyte injury group had worst renal survival, including post-AKI new-onset proteinuria (p = 0.0066) and incident CKD (p = 0.0455). Conclusion: The degree of podocyte injury is an independent risk factor for post-AKI new-onset proteinuria and incident CKD in patients, and patients with more severe podocyte injury exhibit a higher incidence of post-AKI new-onset proteinuria and incident CKD.
Plain Language Summary
Podocyte injury has been proven to be a major cause for poor renal outcomes after acute kidney injury (AKI). However, data of clinical trials are still lacking. Hence, we made a retrospective study evaluating data on 52 AKI patients who underwent kidney biopsy from 6 centers throughout China between January 2012 and June 2023. In the present study, it was found that the degree of podocyte injury, as indicated by foot process fusion, is an independent risk factor for new-onset proteinuria and incident CKD in patients following AKI, and patients with more severe podocyte injury exhibited higher incidence of post-AKI new-onset proteinuria and incident CKD. These findings highlight the critical role of podocyte health in the prognosis of AKI patients and suggest that assessing podocyte injury may aid in identifying individuals at higher risk for adverse renal outcomes.
