To investigate the clinico-pathological characteristics, outcomes and their predictors in malignant hypertension related kidney injury with and without primary glomerular diseases.

Patients with clinical diagnosis of malignant hypertension, biopsy-proven kidney injury caused by malignant hypertension and complete clinical data from January 2010 to December 2018 were retrospectively analyzed. According to clinical and renal pathology, patients were divided into malignant hypertension related kidney injury without primary nephropathy group and with primary nephropathy group. Clinico-pathological characteristics and outcomes were evaluated and compared between malignant hypertension related kidney injury with and without primary glomerular diseases.

Totally 31 biopsy-proven kidney injury patients were analyzed. Among them, there were 18 cases with primary glomerular diseases and 13 cases without primary glomerular diseases, with age of (32.5±6.5) years old and (34.7±8.1) years old, respectively. There were 12 males in both group. The proportion of primary IgA nephropathy was higher (16/18) in the group of malignant hypertension related kidney injury with primary glomerular diseases. Malignant hypertension with primary glomerular diseases patients had lower plasma albunin level [(32.7±6.4) g/L vs (38.5±7.3) g/L, P=0.027], higher 24-hour proteinuria level [(4.03±2.71) g vs (1.45±0.98) g, P=0.002] and higher incidence rates of dysmorphic hematuria (14/18 vs 0, P=0.001) than those without primary glomerular diseases patients. Glomerular sclerosis, mesangial proliferation, tubular atrophy and interstitial fibrosis were more severe in malignant hypertension with primary glomerular diseases patients (all P<0.05), but the ischemic wrinkling of glomerular capillary was more severe in malignant hypertension without primary glomerular diseases (P<0.01). There were no differences of acute or chronic malignant hypertensive injury in small artery and in afferent arterioles between the two groups. Cox regression analysis showed that loss of brush-border with flattening of tubular epithelium was the predictor for renal partial recovery (HR=5.956, 95% CI 1.198-29.614, P=0.029). Kaplan-Meier analysis showed that malignant hypertension patients with primary glomerular diseases had shorter renal survival time than those without primary glomerular diseases [(24.1±9.3) months vs (56.6±12.4) months], and accumulative renal survival rate of malignant hypertension patients with primary glomerular diseases was lower than that without primary glomerular diseases (11.6% vs 53.3%, Log-rank χ²=5.022, P=0.025). Multivariate Cox regression analysis showed that severe tubular atrophy and interstitial fibrosis were independent risk factors for end-stage renal disease in malignant hypertension patients (HR=5.870, 95% CI 1.372-25.112, P=0.017).

Malignant hypertension with primary glomerular diseases patients have more severe clinico-pathological renal impairment and poorer prognosis of long-term renal survival than those without primary glomerular diseases. Acute renal tubular injury (loss of brush-border with flattening of tubular epithelium) is the only predictor of renal function improvement in patients with malignant hypertension and renal impairment within one year. Tubular atrophy/interstitial fibrosis is a risk factor for end-stage renal disease in patients with malignant hypertension. Renal biopsy is an indispensable tool for predicting short-term and long-term renal outcomes.

Hypertension; Pathology, clinical; Prognosis; Biopsy; Glomerular sclerosis; End stage renal disease