 Monitoring of the study: All data will be reported on a specifically designed electronic clinical research form CRF see web site: and will be transferred to the Coordinating Center for data storage and analysis. The Steering Committee will appoint a Data Coordinating Committee to evaluate all CRFs on a continuous way to ensure quality and objectivity of the analysis performed by trained professionals. In order to monitor for patient security, GPs will be asked to actively monitor periodically for adverse events, by asking patients at the time of drug prescription renewal for the occurrence of symptoms or signs that can be related to aggravation of their condition or adverse events of therapy. In selected cases, GPs can refer the patients to the Hypertension Specialist Centre for eventual instrumental and or blood and urinary analyses. Adverse events will be reported in the digital CRF. 