Long-term renal outcome in patients with malignant hypertension: a retrospective cohort study

BACKGROUND Malignant hypertension is frequently complicated by renal insufficiency. Although the survival of this hypertensive emergency has improved, recent data on renal outcome and its predictors are lacking. We assessed renal outcome and its predictors in patients with malignant hypertension. METHODS Retrospective analysis of patients admitted with malignant hypertension in Amsterdam, the Netherlands between August 1992-January 2010. Follow-up data on vital status, renal function and blood pressure (BP) were obtained from the outpatient department and from general practitioners. The primary composite endpoint was end-stage renal disease (ESRD) defined as the start of kidney replacement therapy (KRT) or ≥ 50% decline of estimated glomerular filtration rate (eGFR). The secondary endpoint was all cause mortality. RESULTS A total of 120 patients admitted with malignant hypertension were included. After a median follow-up period of 67 months (IQR 28 to 108 months) the primary endpoint was reached by 37 (31%) patients, whereas 18 patients (15%) reached the secondary endpoint. Twenty-nine (24%) patients started KRT and 8 patients (7%) had an eGFR decline ≥ 50%. After the acute phase (> 3 months after admission), initial serum creatinine and follow-up BP were the main predictors of future ESRD with hazard ratios of 6.1 (95% CI, 2.2-17) for patients with initial serum creatinine ≥ 175 μmol /L and 4.3 (95% CI, 1.4-14) for patients with uncontrolled hypertension. CONCLUSIONS Progressive renal function decline leading to ESRD remains a major threat to patients with malignant hypertension. BP control during follow-up was an important modifiable predictor of renal outcome.