HYPERTENSION AND OUTCOMES RESEARCH - FROM CLINICAL-TRIALS TO CLINICALEPIDEMIOLOGY

Outcomes research seeks to identify effective evidence-based methods o f providing the best medical care. While randomized clinical trials (R CT) usually provide the dearest answers, they are often not done or no t practicable. More than a decade after the introduction of calcium ch annel blockers and angiotensin converting enzyme (ACE) inhibitors, cli nical trial data about their effect on major disease endpoints in pati ents with hypertension are still not available. The primary alternativ es are the use of randomized trials that include surrogate endpoints, such as level of blood pressure or extent of carotid atherosclerosis, and the use of observational studies that include major disease endpoi nts. Both approaches, their strengths and limitations, are discussed i n detail. The possibility of residual confounding limits the strength of inferences that can be drawn from observational studies. Similarly, the possibility of important drug effects, other than those involving the surrogate endpoint, limits the inferences that can be drawn from randomized trials that rely solely on surrogate outcomes as guides to therapy. In the absence of evidence from large clinical trials that in clude major disease endpoints, treatment decisions and guidelines need to synthesize the best available information from a variety of source s. Consistency of findings across various study designs, outcomes, and populations is critical to the practice of evidence-based medicine an d the effort to maximize the health benefits of antihypertensive thera pies.