Patients will be randomized to either indapamide prolonged-release 1.5 mg/day or hydrochlorothiazide 25 mg/day, given orally. Quinapril will be added from the beginning of the study to allow consistent blood pressure control. Dose of quinapril will be titrated from 10 mg/day to 15 mg/day, and then to 20 mg/day, and up to 40 mg/day, as needed for the blood pressure control. The treatment will be administered to randomized patients for 6 months. Assignment of the study medication will be performed through randomization process. The patients will receive the medication from the Investigator/Co-investigator at every visit scheduled; they will be asked to return, at every visit scheduled, the unused medication and the empty boxes, in order to verify their compliance to the treatment. A treatment compliance of 80-120% is considered satisfactory for the study. If compliance is out of the limits mentioned above, the investigator can decide withdrawal of the patient from the study. In exceptional situations, the treatment can be interrupted for a period of maximum 3 days, without withdrawal of the patient from the study. The administration of the study medication will be documented in appropriate source documents and in the CRF and certified by the Investigator.