Reproducibility of ambulatory blood pressure values and circadian blood pressure patterns in untreated subjects in a 1-11 month interval.
OBJECTIVE
To evaluate in untreated subjects the reproducibility of mean values and four circadian patterns between two ambulatory blood pressure monitoring (ABPM) recordings separated by 1-11 months.


METHODS
We performed a retrospective analysis of 481 individuals (59% women) evaluated by ABPM on two occasions, visit 1 (V1) and 2 (V2), separated by 5.5+0.2 months. Four circadian patterns were defined by night/day systolic blood pressure (SBP) ratios: reverse dippers (RD), ratio >1.0; non-dippers (ND), ratio 0.9-1.0; dippers (D), ratio 0.8-<0.9; and extreme dippers (ED), ratio <0.8. Coefficients of correlation and concordance between the ABPM values at V1 and V2 and the reproducibility of the RD, ND, D and ED patterns were calculated by the percentage of the same profile from V1 to V2.


RESULTS
Mean 24-h blood pressure (BP) at V1 and V2 was 126.8/75.9±0.5/0.5 vs. 126.5/75.7±0.5/0.4 mmHg (NS). Nighttime SBP fall was 9.8±0.4 (V1) and 9.6±0.3% (V2) (NS). The correlation coefficient of ABPM data at V1 vs. at V2 was 0.41-0.69 (p<0.001) and the concordance coefficient was 0.34-0.57 (p<0.01). At V1, 38 subjects were classified as ED (7.9%); D, n=216 (44.9%), 187 as ND (38.9%) and 40 as RD (8.3%). At V2 only 26.3% of ED, 44.9% of D, 54.5% of ND and 40% of RD maintained the same profile as at V1.


CONCLUSIONS
In untreated subjects ABPM has high reproducibility for mean values but only modest reproducibility for circadian profiles, thereby challenging the prognostic value of BP dipping patterns.
Departamento de Medicina & Cintesis, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
Miguel
M
Monte
Departamento de Medicina & Cintesis, Faculdade de Medicina, Universidade do Porto, Porto, Portugal.
Mariana
M
Cambão
Departamento Medicina, Escola Superior de Saúde da Universidade de Aveiro, Aveiro, Portugal.
José
J
Mesquita Bastos
Departamento de Medicina & Cintesis, Faculdade de Medicina, Universidade do Porto, Porto, Portugal. Electronic address: jjpolonia@gmail.com.
Jorge
J
Polónia
D000328:Adult; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006973:Hypertension; D008297:Male; D015203:Reproducibility of Results; D012189:Retrospective Studies
24‐hour ambulatory blood pressure monitoring; Circadian patterns; Dipping; Perfis circadiários; Pressurometria ambulatória de 24 horas; Reproducibility; Reprodutibilidade