Chronopharmacologic individualized and group assessment of outcomes in antihypertensive drug trials

Chronobiologic methods are illustrated for the individualized assessment of the patient's response to antihypertensive medication. In addition to the 24-h mean from blood pressure profiles obtained by ambulatory monitoring, specific endpoints serve as gauges of treatment efficacy. These endpoints include the circadian amplitude, a measure of predictable extent of change within 24 h, and hyperbaric (or hypertensive) indices of excess or load. The latter indices assess the duration and amount of blood pressure excess by comparison to critical thresholds. In view of the large circadian variation characterizing blood pressure, the usual time-invariant limits of 140/90 mm Hg (systolic/diastolic) are replaced by time-specific 90% prediction limits derived from data of clinically healthy peers.< >