The Level of Evidence (LOE) rates the quality of scientific evidence that supports the intervention on the basis of the type, quantity, and consistency of data from clinical trials and other sources Glenn N. Levine, MD, FACC, FAHA Chair, ACC/AHA Task Force on Clinical Practice Guidelines As early as the 1920s, and subsequently in the 1959 Build and Blood Pressure StudyS1.5-1 of almost 5 million adults insured between 1934 and 1954, a strong direct relationship was noted between level of BP and risk of clinical complications and death. In the 1960s, these findings were confirmed in a series of reports from the Framingham Heart Study.S1.5-2 The 1967 and 1970 Veterans Administration Cooperative Study Group reports ushered in the era of effective treatment for The first comprehensive guideline for detec- tion, evaluation, and management of high BP was published in 1977, under the sponsorship of the NHLBI.S1.5-5 In subsequent years, a series of Joint National Committee (JNC) BP guide- lines were published to assist the practice community and improve prevention, awareness, treatment, and control of high The present guideline updates prior JNC reports. 1.1. Methodology and Evidence Review An extensive evidence review, which included literature derived from research involving human subjects, published in English, and indexed in MEDLINE (through PubMed), EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guide- line, was conducted between February and August 2015. 