Malignant hypertension in patients with idiopathic IgA nephropathy

Abstract

Background: Idiopathic IgA nephropathy is one of the main causes of secondary malignant hypertension, especially in Chinese population. But little information has been available about malignant hypertension secondary to IgA nephropathy (IgANMHT). The purpose of this study is to evaluate the clinico-pathological features and outcomes of IgANMHT patients.

Methods: A case control retrospective study was carried out in 45 cases of IgANMHT and 26 cases of primary malignant hypertension (PMHT) diagnosed by renal biopsy. Their clinical features and pathological findings were investigated. Their average follow-up time was 37.4 months. Univariate analysis and multivariate Cox regression analysis were performed to select variables to predict renal survival.

Results: In the study, 1.2% of all the IgA nephropathy patients presented malignant hypertension. The amounts of urine protein excretion and red blood cells in IgANMHT patients were significantly higher, while the levels of serum creatinine were significantly lower than those in PMHT patients. The glomerular injury in IgANMHT patients was more severe than that in PMHT patients. The two characteristic vascular lesions of primary malignant hypertension, proliferative endoarteritis and fibrinoid necrosis were also found in IgANMHT patients but with less severity. Renal survival of IgANMHT patients was significantly higher than that of PMHT patients (p = 0.0043). However, log-rank test showed no significant difference in the renal survival between IgANMHT and PMHT patients with similar SCr levels at admission. Multivariate Cox regression analysis revealed that a high amount of urine protein excretion(> or =1.5 g/24 h), mesangial proliferation and elevated serum creatinine (> or =2 mg/dl) were statistically independent risk factors for renal prognosis (RR = 1.90, 2.72, 2.84, respectively). Conversely, strict blood pressure control had a favorable effect on renal prognosis.

Conclusion: The clinico-pathological features and outcomes of IgANMHT patients were different from those of PMHT patients. The renal survival of IgANMHT patients was poor, which was determined by many factors. Early control of proteinuria, early monitoring and strictly controlling blood pressure may contribute to the renal survival.