Interstitial Fibrosis and Tubular Atrophy as a Predictor of Renal Outcomes in Patients with Malignant Hypertension-Related Thrombotic Microangiopathy: A Multicentric Cohort Study.

INTRODUCTION

Interstitial fibrosis and tubular atrophy (IFTA) are common pathological findings in patients with malignant hypertension (mHTN)-related thrombotic microangiopathy (TMA), but their predictive value for renal outcomes in this population remains unclear.

METHODS

This study included patients with mHTN-related TMA confirmed by renal biopsy, admitted to seven different Chinese hospitals from January 2008 to October 2024. Patients were stratified into mild/moderate, severe, and extremely severe IFTA groups based on renal biopsy findings. The primary outcome was renal replacement therapy (RRT) dependence during follow-up, while the secondary outcome was renal function recovery.

RESULTS

A total of 465 patients (median age: 35 years, 87.74% male) were included in this study. During a median follow-up of 24 months, RRT dependence occurred in 182 patients and renal function recovery occurred in 226 patients. Kaplan-Meier analysis showed higher RRT risk with more severe IFTA. Cox regression models showed that severe and extremely severe IFTA groups had hazard ratios of 2.29 (95% CI: 1.59-3.28) and 8.00 (95% CI: 5.36-11.95) for RRT dependence compared to mild/moderate IFTA group (both p < 0.05), even after adjusting for clinical variables and the proportion of global glomerulosclerosis. The cumulative probability of renal function recovery also differed among IFTA groups (log-rank p < 0.001). Extremely severe IFTA negatively impacted renal function recovery in unadjusted analysis, but this significance disappeared after adjusting for the proportion of global glomerulosclerosis.

CONCLUSION

IFTA may serve as a valuable and independent predictor of renal outcomes in patients with mHTN-related TMA, highlighting its importance for clinical decision-making.