Within-visit blood pressure variability: relevant factors in the general population.

The objective of this study was to use a nationwide epidemiological survey to investigate the factors that affect within-visit blood pressure (BP) variability. We analyzed the Korean National Health and Nutrition Examination Survey (KNHNES) data for 2005 (n=5488). We examined three within-visit BP variability parameters that include the following: the alarm reaction (AR), defined as the first BP reading minus the third BP reading; the BP discrepancy, defined as the maximal BP reading minus the minimal BP reading (ΔBPmax); and the s.d. (BPSD). Age, fasting glucose, eGFR, total cholesterol, LDL cholesterol, and the metabolic syndrome (MetS) score were the relevant factors that affected the systolic AR, ΔSBPmax and SBPSD. Multiple linear regression models revealed that age (P<0.0001), the office systolic BP (SBP) level (P<0.0001), the MetS score (P<0.0001), the female gender (P=0.007) and the eGFR (P=0.049) were independently associated with the systolic AR, whereas age (P<0.0001), the office SBP level (P<0.0001), and the female gender (P=0.024 and 0.022) were independently associated with ΔSBPmax and SBPSD, respectively. Within-visit BP variability, especially the variability associated with the SBP, was significantly associated with increased age, female gender and cardiovascular risk factors, such as hypertension, low eGFR and adverse glucose and lipid profiles. In addition, increased age, female gender, the eGFR and the MetS score were independently relevant factors that affected the systolic AR. Systolic within-visit BP variability and systolic AR are associated with cardiovascular risk factors.