REPRODUCIBILITY AND CLINICAL-VALUE OF NOCTURNAL HYPOTENSION - PROSPECTIVE EVIDENCE FROM THE SAMPLE STUDY

Objective To assess whether modifications in the nighttime blood press ure fall caused by antihypertensive treatment predict the regression o f end-organ damage of hypertension. Methods The analysis was performed in patients with essential hypertension and echocardiographically det ected left ventricular hypertrophy involved in the SAMPLE study. For e ach patient, ambulatory blood pressure monitoring and echocardiographi c determination of left ventricular mass index were performed at the e nd of a 4-week wash-out pretreatment period, after 3 and 12 months of treatment with lisinopril or with lisinopril plus hydrochlorothiazide and after a final 4-week placebo period. For each ambulatory blood pre ssure monitoring the 24 h average, daytime average (0600-2400 h), nigh t-time average (2400-0600 h) and day-night difference was computed. Th e percentages of dipper and non-dipper patients (i.e. the patients wit h night blood pressure falls greater and less than 10% of the daytime average, respectively) were also computed. Results The reproducibility of the day-night difference was low, both for comparison of the pretr eatment and final placebo periods (n =170) and for comparison of the t hird and the 12th month of treatment (n = 180). The reproducibility of the dipper-non-dipper dichotomy was also row, 35-40% of patients beco ming non-dippers if they were dippers and vice versa, both with and wi thout treatment The changes in left ventricular mass index after 12 mo nths of treatment were significantly (P < 0.01) related to the changes in 24 h, daytime and night-time blood pressure (r always > 0.33), but this was not the case for the treatment-induced modification of the d ay-night difference (r = -0.03 and -0.008 for systolic and diastolic b lood pressures, respectively). Conclusions Our results show that day-n ight blood pressure changes and the classification of patients into di ppers and non-dippers are poorly reproducible over time. It also provi des the first prospective evidence that treatment-induced changes in d ay-night blood pressure difference are not related to treatment-induce d regression of left ventricular mass index, thus having a limited cli nical significance. (C) 1998 Lippincott-Raven Publishers.