Not nondipping but nocturnal blood pressure predicts left ventricular hypertrophy in the essential hypertensive patients: The Korean Ambulatory Blood Pressuremulticenter observational study

Objective: The aim of this study was to investigate whether nocturnal blood pressure (BP), established on the basis of a single 24-h BP monitoring, is a stronger predictor of left ventricular hypertrophy (LVH) compared with nondipping status in the essential hypertensive patients. Methods: A total of 682 hypertensive patients (mean age 56.1±14.5 years, 50.7% women) who underwent echocardiography were enrolled. 'Nondipping status' was defined as a nocturnal SBP fall less than 10% of daytime mean SBP. LVH was defined as a left ventricular mass index exceeding 54.0 g/m^2.7 in men and 53.0 g/m^2.7 in women. Each patient was categorized in three groups according to the total cardiovascular risk using 2007 European Society of Hypertension/ European Society of Cardiology guidelines as average or low, moderate, and high or very high added risk. Results: Among 682 participants, 184 (26.9%) showed LVH on echocardiography. The proportion of individuals with high or very high added cardiovascular risk profile was 356 (52.1%). In multiple logistic regression analysis, age 56 years at least [odds ratio (OR) 1.047, 95% confidence interval (CI) 1.031-1.063, P<0.0001], female participants (OR 1.751, 95% CI 1.172-2.616, P=0.0062), BMI higher than 24.6 kg/m² (OR 1.178, 95% CI 1.110- 1.250, P<0.0001), smoking (OR 1.793, 95% CI 1.028- 3.127, P=0.0397), and nocturnal SBP at least 127mmHg (OR 1.032, 95% CI 1.009-1.055, P=0.0059) were significant independent predictors for LVH whereas nondipping was not (OR 0.857, 95% CI 0.481-1.528, P=0.6013). Conclusion: These findings suggest that nocturnal BP rather than nondipping may be a better predictor of LVH, especially in secondary or tertiary referral hospital setting targeting relatively high cardiovascular risk patients.