 This study has been designed to assess whether a follow-up strategy based on a strict cooperation between GPs and hypertension specialists allows the use of diuretics as first-line antihypertensive treatment with a persistence on assigned therapy equivalent to that achieved by using any other first line antihypertensive therapy. Assessment of safety and efficacy for controlling cardiovascular risk will be also performed as secondary endpoint. In fact, in contrast with trials comparing single-drug effects, this study compares two strategies of antihypertensive management, based on either real-word prescriptions or a regimen in which thiazide diuretics represent a forced first line antihypertensive therapy. If our hypothesis will be demonstrated diuretics might be suggested as an efficient and economic first line antihypertensive treatment, on which build up optimal antihypertensive therapy by adding other class drugs, in all patients, provided that the follow-up procedure is based on the proposed organization. This approach will be of great utility for the National Health Care System to reduce costs, since, a large part of the economic burden is related to the use of antihypertensive medications more expensive than thiazides, as first line agents, in particular so far only 40 of the hypertensive patients receive diuretics in their therapy. 