Epidemiology of Uncontrolled Hypertension in the United States

Hypertension is a powerful risk factor for fatal and nonfatal cardiovascular disease events. Data from observational studies indicate that this risk is continuous, without evidence of a threshold, down to blood pressures as low as 115/75 mm Hg.1 Randomized controlled trials have convincingly shown that treatment of hypertension reduces the risk of stroke, coronary heart disease, congestive heart failure, and mortality.2,3 Because hypertension currently affects 1 in 4 American adults (≈65 million people in 1999 to 2000)4 and may affect >90% of individuals during their lifetimes,5 adequate control of blood pressure is of enormous public health importance. However, recent studies indicate that as many as two thirds of those with hypertension in the United States are either untreated or undertreated.6 Studies based on national data and community cohorts have shed light on the reasons underlying this poor control, but several questions remain unanswered. In this article, we review contemporary data on the epidemiology of uncontrolled hypertension in the United States by (1) defining what constitutes “controlled hypertension”; (2) describing the current magnitude of the problem, including temporal trends; (3) summarizing the public health consequences of uncontrolled hypertension; (4) examining the clinical correlates of uncontrolled hypertension and appraising the patient- and physician-related factors related to poor control of blood pressure; and (5) identifying future research directions, including potential interventions to address this problem. In this article, “uncontrolled hypertension” signifies blood pressure that is inadequately treated rather than blood pressure that is resistant to treatment, as might be observed with secondary causes of hypertension such as renal artery stenosis.The definition of high blood pressure has changed over time and differs between guidelines proposed by expert bodies. Variation in the definition of hypertension influences the number of people classified as having uncontrolled hypertension7 and may contribute …