ERC members may include methodologists, epidemiologists, healthcare providers, and biostatisticians. The recommendations developed by the writing committee on the basis of the systematic review are marked with SR. Guideline-Directed Management and Therapy The term guideline-directed management and therapy (GDMT) encompasses clinical evaluation, diagnostic test- ing, and pharmacological and procedural treatments. For these and all recommended drug treatment regimens, the reader should confirm the dosage by reviewing product insert material and evaluate the treatment regimen for contraindica- tions and interactions. The recommendations are limited to drugs, devices, and treatments approved for clinical use in the United States. Class of Recommendation and Level of Evidence The Class of Recommendation (COR) indicates the strength of the recommendation, encompassing the estimated magni- tude and certainty of benefit in proportion to risk. 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. 