To compare the diagnostic performance of successive blood pressure (BP) measurements in borderline and not borderline blood pressure levels.Design and method:
834 hypertense patients or suspected of hypertension have had their BP measured: 7 successive nurse measures using automated equipment, and 24-hour ambulatory blood pressure monitoring (ABPM), both were made following protocols of European Guidelines. For all patients were calculated the average of third to seven nurse readings (3–7BPa). Also, we classified each blood pressure value using the definitions of 2013 European Society of Hypertension and of the European Society of Cardiology Guidelines for the management of arterial hypertension. Awake blood pressure average (ABPa) was used as gold standard. We calculated for systolic and diastolic 3–7BPa, the concordance correlation coefficient (Pc) and area under the curve (AUC), firstly in the full sample, and after in borderline grades of BP (high normal and grade 1) and not borderline grades (optimal, normal, grade 2 and 3). The confidence interval of variables was calculated for comparison between the groups.Results:
Data from 834 patients were analyzed. The results are demonstrated in table 1. At full sample. 3–7 BPa shows a good concordance with ABPa, 0,63 and 0,72, for systolic and diastolic Pc respectively. The AUC results (0,82 and 0,85 systolic and diastolic) show, that it separates well hypertense from normotensive patients. However, in comparison between borderline against not borderline group, 3-BPa shows a significant differences in Pc systolic (0,31 vs 0,73), diastolic Pc (0,53 vs 0,78), AUC systolic (0,68 vs 0,91) and AUC diastolic (0,77 vs 0,89). When the results of borderline group were compared with all sample the same difference were found, Pc systolic (0,31 vs 0,63), diastolic Pc (0,53 vs 0,72), systolic AUC (0,68 vs 0,82) and diastolic AUC (0,77 vs 0,85). There is a significant difference between not borderline group and all sample for systolic values of Pc (0,73 vs 0,63) and systolic AUC (0,91 vs 0,82).Conclusions:
3–7BPa demonstrated good precision and correlation with awake blood pressure. But, loses significantly this performance in patients with high normal and grade 1 of hypertension.