20 Aug Introduction and purposes
For several years the European Society of Hypertension (ESH) and the European Society of Cardiology (ESC) decided not to produce their own guidelines on the diagnosis and treatment of hypertension but to endorse the guidelines on hypertension issued by the WorldHealth Organization (WHO) and International Society of Hypertension (ISH) [1,2] with some adaptation to reflect the situation in Europe. However, in 2003 the decision was taken to publish ESH/ESCspecific guidelines  based on the fact that, because the WHO/ISH Guidelines address countries widely varying in the extent of their health care and availability of economic resource, they contain diagnostic and therapeutic recommendations that may be not totally appropriate for European countries. In Europe care provisions may often allow amore in- depth diagnostic assessment of cardiovascular risk and organ damage of hypertensive individuals as well as a wider choice of antihypertensive treatment.
The 2003 ESH/ESC Guidelines  were well received by the clinical world and have been the most widely quoted paper in the medical literature in the last two years . However, since 2003 considerable additional evidence on important issues related to diagnostic and treatment approaches to hypertension has become available and therefore updating of the previous guidelines has been found advisable.
In preparing the new guidelines the Committee established by the ESH and ESC has agreed to adhere to the principles informing the 2003 Guidelines, namely 1) to try to offer the best available and most balanced recommendation to all health care providers involved in the management of hypertension, 2) to address this aim again by an extensive and critical review of the data accompanied by a series of boxes where specific recommendations are given, as well as by a concise set of practice recommendations to be published soon thereafter as already done in 2003 ; 3) to primarily consider data from large randomized trials but also to make use, where necessary, of observational studies and other sources of data, provided they were obtained in studies meeting a high scientific standard; 4) to emphasize that guidelines deal with medical conditions in general and therefore their role must be educational and not prescriptive or coercive for the management of individual patients who may differ widely in their personal, medical and cultural characteristics, thus requiring decisions different from the average ones recommended by guidelines; 5) to avoid a rigid classification of recommendations by the level or strength of scientific evidence . The Committee felt that this is often difficult to apply, that it can only apply to therapeutic aspects and that the strength of a recommendation can be judged from the way it is formulated and from reference to relevant studies. Nevertheless, the contribution of randomized trials, observational studies, meta-analyses and critical reviews or expert opinions has been identified in the text and in the reference list.
The members of the Guidelines Committee established by the ESH and ESC have participated independently in the preparation of this document, drawing on their academic and clinical experience and applying an objective and critical examination of all available literature. Most have undertaken and are undertaking work in collaboration with industry and governmental or private health providers (research studies, teaching conferences, consultation), but all believe such activities have not influenced their judgement. The best guarantee of their independence is in the quality of their past and current scientific work. However, to ensure openness, their relations with industry, government and private health providers are reported in the ESH and ESC websites (www.eshonline.org and www.escardio.org) Expenses for the Writing Committee and preparation of these guidelines were provided entirely by ESH and ESC.