Patients were included if their diastolic BP (DBP) was ≥95 mmHg and/or systolic (SBP) ≥160 mmHg despite at least 4 weeks of monotherapy. Patients were informed that the purpose of the study was to see if BP could be adequately lowered with a combination of two antihypertensive drugs. They were not informed that the study was actually designed to assess adherence to drug therapy, as this would possibly affect study outcome. The study was approved by the Hospital Ethics Committee and written informed consent was obtained