Factors Predicting Renal Outcomes in Hypertensive Emergencies With Severe Renal Impairment: A Single-Center Retrospective Study

Background and aims: Hypertensive emergencies, characterized by elevated blood pressure (BP) and multiple organ damage, have poor prognosis. Patients occasionally show gradual improvement in renal function with appropriate antihypertensive treatment despite renal impairment. However, reports analyzing factors predicting prognosis in patients with hypertensive emergencies and severe renal impairment are limited. This retrospective study aimed to investigate clinical features and predictors of renal outcomes in such patients.

Methods: Patients admitted to our hospital diagnosed with hypertensive emergency with severe renal impairment (serum creatinine [Cr] level > 2.5 mg/dL) between 2007 and 2021, were enrolled and divided into two groups: those who received renal replacement therapy (RRT) after 3 years (RRT group) and those who did not (non-RRT group); clinical characteristics and laboratory data were compared.

Results: Fifteen patients were enrolled, with a median age and serum Cr level of 48 years and 5.97 mg/dL, respectively. No significant between-group difference was observed in serum Cr levels or kidney size. However, the non-RRT group exhibited significantly higher levels of serum lactate dehydrogenase (LDH) levels and significantly lower platelet counts (PLT), suggesting development of microangiopathic hemolysis due to severe endothelial damage. Furthermore, the non-RRT group exhibited lower serum potassium levels than the RRT group, accompanied by high plasma renin activity and serum aldosterone levels, suggesting activation of the renin-angiotensin system (RAS). In the non-RRT group, serum Cr, LDH, potassium levels, and PLT improved significantly after treatment.

Conclusions: Serum LDH, potassium levels, and PLT are useful predictors of renal prognosis in hypertensive emergencies with extremely poor renal function. In some cases, severe renal damage can be ameliorated by appropriate antihypertensive therapy. A positive response to treatment often signifies a favorable prognosis. Furthermore, early initiation of RAS inhibitors may be beneficial for lowering BP and providing renal protection.