The Impact of Obesity on Nighttime Blood Pressure Dipping

Abstract

Background and objectives: It is commonly known that obesity not only increases arterial hypertension (HT) risk but also impacts on the response to antihypertensives. This study aimed to assess blood pressure (BP) parameters based on Ambulatory Blood Pressure Measurement (ABPM) in obese patients. Materials and Methods: The study group consisted of 128 patients with obesity (BMI ≥ 30 kg/m2), with an average age of 43.25 years (±12.42), including 55 males and 73 females. They were divided into 2 groups: 1-with BMI ≥ 30 kg/m2 and <40 kg/m2, 2-with BMI ≥ 40 kg/m2. Each patient underwent 24-h blood pressure monitoring. The average 24-h, daytime and nighttime systolic and diastolic pressure, as well as 24-h mean heart rate and % of nocturnal dip, were assessed. Results: Mean BMI in group 1 was 34.73 kg/m2 (±2.96), and in group 2 it was 47.6 kg/m2 (±6.3). Group 1 was significantly older than group 2 (46.5 vs. 39 years old). The analysis of ABPM revealed significantly higher BP values in all measurements in group 2 (i.e., systolic blood pressure (SBP) 24 h median = 132 mmHg; diastolic blood pressure (DBP) 24 h median = 84 mmHg). The nocturnal dip was greater in group 1 (8.95%). Mean 24-h heart rate was also higher in group 2 (median = 76 beats/min) than group 1 (median = 67.5 beats/min). More than half of patients in group 2 had been previously treated for HT, and based on ABPM, new HT was diagnosed in 6 patients from group 1 and 14 patients from group 2. Three groups of patients were identified based on nighttime dip: dipper, non-dipper, and reverse-dipper. No patient of the extreme dipper type was found. Group 2 comprised of significantly more patients of the reverse-dipper type. Conclusions: Patients with extreme morbid obesity frequently exhibit HT of the reverse-dipping pattern. This type is often linked with a higher risk of more advanced cardiovascular illness.