Nocturnal dipping status and the association of morning blood pressure surge with subclinical target organ damage in untreated hypertensives.

The authors aimed to investigate the association between sleep-through morning surge (MS) in blood pressure (BP) and subclinical target organ damage in untreated hypertensives with different nocturnal dipping status. This cross-sectional study included 1252 individuals who underwent anthropometric measurements, serum biochemistry evaluation, 24-hour ambulatory blood pressure monitoring, echocardiography, and carotid ultrasonography. Left ventricular mass index, left atrial dimension, and carotid intima-media thickness were evaluated. Participants were grouped according to nocturnal systolic BP dipping rate (388 dippers, 10%-20%; 674 non-dippers, 0%-10%; 190 reverse dippers, <0%). Twenty-two extreme dippers were excluded. While reverse dippers exhibited the most severe signs of damage, only dippers showed significant and positive correlation between MS and hypertension-mediated organ damage (all P < .05), with significant area under the receiver operating characteristic curve for discriminating left ventricular hypertrophy (0.662), left atrial enlargement (0.604), and carotid intima-media thickening (left, 0.758; right, 0.726; all P < .05). MS showed significant association with subclinical organ damage on both logistic and multiple linear regression analysis adjusted for age, sex, body mass index, smoking status, and alcohol consumption status, as well as for the levels of fasting blood glucose, uric acid, serum creatinine, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol, even when 24-hour, daytime, nocturnal, and morning systolic BP were included (odds ratio >1 and P < .01 for all types of damage). Besides race, nocturnal dipping status might affect the role of MS in subclinical target organ damage, with a significant association only in dippers, independent of other systolic BP parameters. Dipping status might account for the discrepancies across previous reports.