Drug nonadherence is a common but often overlooked cause of hypertensive urgency and emergency at the emergency department.

Objectives: Over 70% of patients who visit the emergency department with a hypertensive emergency or a hypertensive urgency have previously been diagnosed with hypertension. Drug nonadherence is assumed to play an important role in development of hypertensive urgency and hypertensive emergency, but exact numbers are lacking. We aimed to retrospectively compare characteristics of patients with hypertensive urgency and hypertensive emergency and to prospectively quantify the attribution of drug nonadherence.