Prevention of hypertension and associated cardiovascular disease: a 1991 statement. Conclusions from a joint WHO/ISH meeting.

This statement is the result of the discussion held at the end of a WHO/ISH Meeting on the Prevention of Hypertension and Cardiovascular Disease held at Porto Cervo (Italy) in June 1995. The objective of the discussion was to reconsider the 1989 and 1991 statements (1,2) agreed upon at the end of the previous WHO/ISH Meetings in Goteborg (Sweden) and Camogli (Italy) in the light of recent scientific evidence.In preparing this statement the Committee has acknowledged that the strength of the recommendations for therapy and for prevention should both be based on the level of published evidence: the strongest evidence, and therefore the strongest recommendations, are those based on randomized controlled trials, but useful recommendations can also be based on lower levels of evidence, such as observational surveys, subgroup analysis of randomized trials, non-randomized trials, case series and clinical experience.