PREDICTORS OF DIURNAL BLOOD-PRESSURE CHANGES IN 2042 SUBJECTS WITH ESSENTIAL-HYPERTENSION

Objective To determine the independent predictors of day-night blood p ressure changes in a large population of subjects with essential hyper tension. Methods We studied 2042 white untreated subjects with essenti al hypertension (mean age 52 years, range 17-93, 1052 men) who underwe nt 24 h ambulatory blood pressure monitoring on an outpatient basis, N ight-time workers were excluded from analysis. Results For both sexes, the changes in systolic and diastolic blood pressures from day to nig ht decreased progressively with age and increased with the reported du ration of sleep, The 1207 employed subjects who underwent ambulatory b lood pressure monitoring during a usual working day had greater day-ni ght blood pressure differences than did those who did not work (16.2 v ersus 14.0%), By using multiple regression analysis we assessed the in dependent association of several variables with the diurnal blood pres sure changes, Age and diabetes for both sexes, and clinic blood pressu re in men, were inversely associated with the nocturnal fall in blood pressure, The duration of sleep and the occurrence of blood pressure m onitoring during a normal work day predicted a greater day-night blood pressure difference for both sexes; smoking predicted a greater noctu rnal fall in blood pressure for women. Conclusions Age is associated w ith an important and progressive attenuation of the day-night blood pr essure difference in untreated and unrestricted subjects with essentia l hypertension, Other factors influencing diurnal blood pressure varia tions include clinic blood pressure, diabetes, the reported duration o f sleep, smoking habits and working activity during blood pressure mon itoring. These factors should be treated as potential confounders in t he analysis of the relationship between diurnal blood pressure changes and target organ damage or prognosis.