SURROGATE END-POINTS FOR PROGNOSIS OF HYPERTENSION: The identification of surrogate measures of cardiovascular risk in patients with hypertension may allow clinicians to better estimate a patient's long-term prognosis and monitor the effects of antihypertensive therapy in reducing risk and thereby reducing the cardiovascular complications of hypertension. PROGNOSTIC LIMITATIONS OF OFFICE BLOOD PRESSURE: Previous studies have shown that office blood pressure may predict the incidence of fatal and nonfatal cardiovascular complications of hypertension. However, evidence also suggests that the predictive value of office blood pressure is limited and that it does not provide accurate estimates of the changes in the cardiovascular risk profile that can occur with antihypertensive treatment. PROGNOSTIC VALUE OF 24-H AMBULATORY BLOOD PRESSURE: Cross-sectional studies have shown that 24-h average blood pressure values are more closely correlated with hypertensive target-organ damage [e.g. left ventricular hypertrophy (LVH), retinopathy, increased serum creatinine, albuminuria, and microalbuminuria] than are office blood pressure values. Although longitudinal evidence of the clinical relevance of 24-h ambulatory blood pressure monitoring is limited, preliminary data from a recently completed trial, the Study on Ambulatory Pressure and Lisinopril Evaluation (SAMPLE), have clearly shown the superiority of 24-h blood pressure monitoring over office readings in predicting the regression of LVH in hypertensive patients following treatment to reduce blood pressure.