NOCTURNAL BLOOD-PRESSURE IN NORMOTENSIVE SUBJECTS AND THOSE WITH WHITE COAT, PRIMARY, AND SECONDARY HYPERTENSION

Objective-To compare the mean nocturnal blood pressure of patients wit h various forms of renal and endocrine hypertension with that in patie nts with primary and white coat hypertension, and normal blood pressur e. Design-Ambulatory monitoring of blood pressure over 24 hours in a p rospective study. Setting-Two German centres for outpatients with hype rtension and kidney diseases. Subjects-176 normotensive subjects, 490 patients with primary hypertension including mild and severe forms, 42 with white coat hypertension, 208 patients with renal and renovascula r hypertension, 43 with hypertension and endocrine disorders, and thre e with coarctation of the aorta. Main outcome measures-Fall in nocturn al blood pressure. Results-Blood pressure in normotensive subjects fel l by a mean of 14 mm Hg (11%) systolic and 13 mm Hg (17%) diastolic ov ernight (2200 to 0600). The falls in patients with primary and white c oat hypertension were not significantly different. In all patients wit h renal and renovascular hypertension, however, the fall was significa ntly reduced (range of fall from 3/3 mm Hg to 7/9 mm Hg). In patients with hypertension and endocrine disorders the pattern of night time bl ood pressure was not uniform: patients with hyperthyroidism, primary h yperaldosteronism, and Cushing's syndrome had significantly smaller re ductions in blood pressure (6/8, 4/7, 3/6 mm Hg, respectively). In pat ients with phaeochromocytoma the mean night time blood pressure increa sed by 4/2 mm Hg. In patients with hypertension, primary hyperparathyr oidism, and unoperated coarctation of the aorta the falls in blood pre ssure were normal. Conclusions-In normotensive subjects and those with primary hypertension there is usually a reduction in blood pressure a t night. In all renal forms of secondary hypertension and in most endo crine forms the reduction in blood pressure is only a third to a half of normal. Patients with primary hyperparathyroidism and unoperated co arctation of the aorta show a normal reduction.