Home blood pressure and circadian variation of blood pressure in the evaluation of hypertensive patients.
Clinical blood pressures measured at clinic by physician were higher than home blood pressures measured at home by patients in the majority of untreated patients with essential hypertension, but equivalent or lower in some patients. Clinic minus home blood pressure (delta P) were correlated with the levels of clinic blood pressure (r = 0.51, p less than 0.005 for systolic; r = 0.35, p less than 0.02 for diastolic blood pressure, respectively). The systolic delta P might be greater in the middle-aged women, especially in the fifties of females than the age-matched males (p less than 0.05). The delta P could not be altered by any antihypertensive drugs with the exception of systolic delta P with diuretic alone. The blood pressure tended to remain more stable throughout the 24-hour period in proportion as the severity of hypertension increased. The observation of circadian variation in blood pressure disclosed that the blood pressure was lower in the morning, but increased gradually, resulting in the relatively high blood pressure between the afternoon and evening in the low renin and volume expanded type of hypertension. On the contrary, the blood pressure was already high in the early morning in hypertensive patients characterized by the accelerated renin-angiotensin system and contracted volume factor.