Ambulatory blood pressure monitoring profiles in a cross-sectional analysis of a large database of normotensive and true or suspected hypertensive patients

Abstract

Objective: To assess ambulatory blood pressure monitoring (ABPM) circadian patterns and their determinants in a large sample of normotensive and hypertensive patients.

Methods: A total of 26170 individual ABPM recordings from 1995 to 2015 were analyzed. Mean office blood pressure (OBP), 24-hour blood pressure (BP), daytime BP and nocturnal BP were measured. Circadian patterns were classified by nocturnal systolic BP fall as extreme dipper (ED, ≥20%), dipper (D, 10%-19.9%), non-dipper (ND, 0%-9.9%), and reverse dipper (RD, <0%).

Results: The population were 52% female, aged 58±15 years, mean body mass index (BMI) 27±5 kg/m². Using ABPM criteria of normalcy, 22.8% were normotensives (NT), 19.1% were untreated hypertensives, 29.7% were controlled hypertensives and 28.4% were treated but uncontrolled hypertensives. Among NT, 60.7% were white-coat hypertensive. In controlled hypertensives 62.4% had OBP ≥140/90 mmHg. In treated but uncontrolled hypertensives 8.2% had masked uncontrolled hypertension. ABPM values were lower than OBP in all cases. In all subgroups the most common pattern was D (42-50%), followed by ND (35-41%), ED (7-11%) and RD (4-11%). Age and BMI were determinants of attenuation of nocturnal BP fall and ND+RD. The proportion of ND+RD was higher in patients with BMI >30 kg/m² vs. others (46.5 vs. 42.9%, p<0.01) and in those aged ≥65 vs. <65 years (54.9. vs. 33.1%, p<0.00). Nocturnal BP fall was greater in NT than in hypertensives (11.3±6.7 vs. 9.9±7.9%, p<0.000).

Conclusions: There was a marked discrepancy between office and ABPM values. The rates of control on ABPM were more than double those on OBP. Non-dipping occurred in >43%, including in NT. Age and BMI predicted non-dipping.

Keywords: 24h ambulatory blood pressure; Circadian blood pressure rhythm; Non-dipping blood pressure; Padrão non dipping; Perfis circadiários da pressurometria ambulatória; Pressurometria ambulatória de 24 horas.