Cardiovascular risks of hypertension: lessons from observational studies

Hypertension is an acknowledged major risk factor for cardiovascular disease and death in both men and women. Despite a historical focus by clinicians on the importance of diastolic blood pressure (DBP) risks, epidemiologic data from numerous large-scale studies have clearly demonstrated that both systolic blood pressure (SBP) and DBP are important determinants of cardiovascular risk. Recent analyses have described notable risks associated with isolated and borderline elevations of SBP, which predominate in the elderly, emphasizing the independent contribution of elevated SBP in determining overall risk. Overviews of large-scale treatment trials show that antihypertensive drug treatment confers a favorable net clinical benefit in patients with diastolic and isolated systolic hypertension, and the magnitude of risk reduction is comparable to that expected from the observational data. However, at any level of SBP or DBP, the absolute magnitude of risk varies widely depending on the burden of coexisting risk factors present. Therefore, it is essential that decisions regarding the urgency, risks and benefits of antihypertensive drug treatments be informed by accurate determinations of overall cardiovascular risk.