Nighttime vs. daytime blood pressure as a predictor of changes in left ventricular mass in hypertensive subjects

Left ventricular hypertrophy (LVH) conveys an increased risk of cardiovascular morbidity and mortality. We aimed to compare the prognostic value of daytime and nighttime blood pressure (BP) on the changes in LVH status in newly diagnosed hypertensive subjects. Three hundred and five hypertensive, nondiabetic subjects (mean age 51.1 +/- 10.2 years, 190 men) were prospectively studied for a mean period of 42 +/- 17 months. At baseline and last follow-up visit, all patients underwent office and ambulatory BP monitoring, as well as echocardiographic assessment. We defined the following: LVH development/LVH persistence as the new-onset LVH at the end of follow-up or the presence of LVH at both baseline and the end of follow-up; left ventricular mass index (LVMI) reduction as a decline in LVMI at the end of follow-up of X >= 15% compared with the baseline value. Multivariate Cox regression analyses revealed that baseline nighttime systolic BP was a significant predictor of LVH development/LVH persistence during follow-up (hazard ratio = 1.066, P = 0.02), whereas baseline daytime systolic BP was not. Moreover, the reduction of nighttime systolic BP is related to an almost threefold increase in the probability of LVMI reduction, independently of daytime BP reduction. In conclusion, nighttime BP constitutes a better prognosticator of left ventricular mass alterations over time in treated essential hypertensive patients than does daytime BP.