Introduction and objective: Blood pressure variability (BPV) within 24 h or between visits has been found to represent an independent risk factor for cardiovascular disease. The present study was aimed at determining whether a clinical significance can be given also to the BP variations occurring within a single clinical visit.
Methods: BPV was quantified as coefficient of variation and as standard deviation (SD) of the mean of three systolic SBP values within a visit in the context of a large-cross subclinical survey (BP-CARE) of treated hypertensive patients living in Eastern European countries. The study population was divided into coefficient of variation and SD quartiles and for each quartile a relationship was sought with a large number of cardiovascular risk factors based on patients' history, physical and laboratory examinations.
Results: The 6425 hypertensive patients had an age of 59.2 ± 11 years (mean ± SD); they were equally distributed by sex and displayed an average SD and coefficient of variation amounting to 5.1 ± 6.2 mmHg and 3.5 ± 4.0%, respectively. Compared with the lowest coefficient of variation quartile (Q1), patients in the highest quartile (Q4) showed a significantly greater prevalence of several cardiovascular risk factors, such as age (Q1: 58.5 ± 11 vs. Q4: 60.3 ± 11 years, P < 0.001), serum total cholesterol (Q1: 213.0 ± 46 vs. Q4: 216.4 ± 51 mg/dl, P < 0.05), blood glucose (Q1: 106.2 ± 35 vs. Q4: 109.8 ± 39 mg/dl, P < 0.005), previous cardiovascular events (Q1: 57.4 vs. Q4: 63.9%, P < 0.001), and resistant hypertension (Q1: 26.3 vs. Q4: 34.1%, P < 0.001). They also showed higher office (Q1: 143.2 ± 18 vs. Q4: 154.3 ± 19 mmHg, P < 0.001) and 24-h ambulatory SBP values (Q1: 134.8 ± 17 vs. Q4: 141.2 ± 18 mmHg, P < 0.001). Similar results were obtained when BPV was expressed as SD.
Conclusion: Our study provides evidence that greater within-visit BP variabilities are associated with a worse cardiovascular risk profile. This suggests that even this type of BPV may have clinical significance.