Prevalence and Characteristics of Isolated Nocturnal Hypertension in Treated Patients

Objective: This study aimed to identify the prevalence and characteristics of isolated nocturnal uncontrolled hypertension (INUCH) in treated patients. Design and method: Participants (n=701) aged >=20 on antihypertensive drugs were recruited via advertisements between August 2018 and April 2020 and underwent 3-day office (3 readings every visit) and 24-hour ambulatory blood pressure (BP) measurements. Hypertension phenotypes were categorized as controlled (CH), isolated daytime uncontrolled (IDUCH), INUCH, and day-night uncontrolled hypertension (DNUCH), according to 2023 ESH guidelines. Results: Of 650 participants with valid BP data, INUCH prevalence was 32.3% (34.9% in patients with office BP <140/90 mmHg), with a higher prevalence of men and drinkers than CH. INUCH patients exhibited higher office systolic (SBP) and diastolic BP (DBP) than CH. INUCH prevalence was higher in patients with office BP <140/90 mmHg (34.9% vs. 18.9% for >=140/90 mmHg). INUCH rates decreased across office BP categories (37.6% in optimal, 38.5% in normal, 27.9% in high-normal, and 18.9% in uncontrolled office BP), while DNUCH increased (10.6% in optimal, 24.2% in normal, 53.5% in high-normal, and 71.7% uncontrolled office BP). Among INUCH patients, 48.1% had isolated uncontrolled DBP, 8.6% had isolated uncontrolled SBP, and 43.3% had both. Those with isolated uncontrolled DBP were younger (p=0.016), more males (p=0.017), and drinkers (p=0.006) than those with isolated uncontrolled SBP and DBP. Multivariate analysis in patients with office BP <140/90 mmHg revealed age and alcohol drinking as positive and high-normal OBP as negative INUCH factors. Isolated uncontrolled DBP and uncontrolled SBP and DBP were significantly associated with INUCH. Brachial-ankle pulse wave velocity was significantly higher in INUCH patients than in CH patients after excluding patients with isolated uncontrolled DBP. Conclusions: The considerable INUCH occurrence in normal/optimal office BP patients implies treatment challenges. The association of alcohol consumption with INUCH underscores moderation in hypertension treatment. Although the prognostic significance of INUCH with isolated uncontrolled DBP was undetermined, distinguishing between isolated uncontrolled DBP and uncontrolled SBP seems necessary in evaluating the prognostic significance of INUCH.