Models of the clinical and economic impact of hypertension and the benefits of blood pressure (BP) control typically focus on either diastolic or systolic blood pressure (DBP or SBP) but not both. For example, our previously-reported Hypertension Burden of Illness Model considered only DBP and therefore could not address the issue of systolic hypertension. OBJECTIVE: To estimate the clinical and economic benefits of achieving both DBP and SBP goals in treated hypertensives. METHODS: We revised and updated our existing model which was designed to forecast cardiovascular disease (CVD) incidence and direct medical-care costs for specified populations, such as the membership of a managed-care plan, and simulates the effect of programs to improve BP control. The underlying Framingham Heart Study (FHS) risk equations, which previously quantified the relationship between DBP and CVD risk, were replaced with new FHS equations that incorporated both DBP and SBP. The economic costs of CVD were estimated as in the earlier version using major national health surveys and healthcare cost databases. RESULTS: We estimate that 9.6 million persons aged 40-79 years in the U.S. are treated for hypertension but continue to have uncontrolled DBP (?90 mmHg) or SBP (?140 mmHg). If all of these patients were treated to high-normal BP (<140/90), an estimated 414,000 CVD events would be prevented over 10 years resulting in medical care cost savings of $6.5 billion, an average of 43 events and $674,000 per 1000 patients. If such treatment were limited to patients with a history of CVD, it would prevent an estimated 59 events and save $761,000 per 1000 patients. CONCLUSION: Risk assessment and intervention programs that target treated but uncontrolled hypertensives can be expected to yield substantial economic benefits in addition to preventing cardiovascular morbidity and mortality.