Korean Circ J.  2016 May;46(3):365-373. 10.4070/kcj.2016.46.3.365.

Higher Blood Pressure Variability in White Coat Hypertension; from the Korean Ambulatory Blood Pressure Monitoring Registry

• Kang IS
• Pyun WB
• Shin J
• Ihm SH
• Kim JH
• Park S
• Kim KI
• Kim WS
• Kim SG
• Shin GJ

• KMID: 2344449
• DOI: http://doi.org/10.4070/kcj.2016.46.3.365

Abstract

BACKGROUND AND OBJECTIVES
Blood pressure variability (BPV) was recently shown to be a risk factor of stroke. White coat hypertension (WCH) used to be regarded as innocuous, but one long-term follow-up study reported that WCH increased stroke rate compared to normotension (NT). In this study, we aimed to evaluate the relationship between WCH and BPV.
SUBJECTS AND METHODS
We analyzed 1398 subjects from the Korean Ambulatory Blood Pressure Registry, who were divided into NT (n=364), masked hypertension (n=122), white coat hypertension (n=254), and sustained hypertension (n=658) groups.
RESULTS
Baseline characteristics were similar among groups. The average real variability (ARV), a highly sensitive BPV parameter, was highest in the WCH group, followed by the sustained hypertension, masked hypertension, and NT groups. The results persisted after being adjusted for covariates. The WCH vs. sustained hypertension results (adjusted mean±standard error) were as follows: 24-h systolic ARV, 22.9±0.8 vs. 19.4±0.6; 24-h diastolic ARV, 16.8±0.6 vs. 14.3±0.5; daytime systolic ARV, 21.8±0.8 vs. 16.8±0.6; and daytime diastolic ARV, 16.2±0.6 vs. 13.4±0.5 (p<0.001 for all comparisons).
CONCLUSION
From the registry data, we found that subjects with WCH or masked hypertension had higher BPV than NT. However, long-term follow-up data assessing the clinical influences of WCH on stroke are needed.

Keyword

Blood pressure monitoring; Ambulatory; Blood pressure variability; White coat hypertension

MeSH Terms

Blood Pressure Monitoring, Ambulatory*
Blood Pressure*
Follow-Up Studies
Hypertension
Masked Hypertension
Risk Factors
Stroke
White Coat Hypertension*

Figure

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  Fig. 1 Flow chart of study population. Kor-ABP: Korean ambulatory blood pressure, BP: blood pressure.

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  Fig. 2 The differences between SD and ARV within groups. The WCH group showed a large difference in the SD and ARV, which was followed by SHT. The NT and MHT groups did not show differences in daytime systolic BPV (A) or daytime diastolic BPV (B). *p<0.001. SD: standard deviation, ARV: average real variability, WCH: white coat hypertension, SHT: sustained hypertension, NT: normotension, MHT: masked hypertension, BPV: blood pressure variability, NS: non-significant.

• 

  Fig. 3 The difference in ARV between groups. The WCH group shows the highest value of ARV compared to the other three groups. ARV values represent means adjusted for sex, age, diabetes mellitus, body mass index, serum creatinine, and cholesterol level. (A) Daytime SBP ARV, (B) daytime DBP ARV, (C) 24-hour SBP ARV, (D) 24-hour DBP ARV. *p<0.001. ARV: average real variability, WCH: white coat hypertension, SBP: systolic blood pressure, DBP: diastolic blood pressure, BPV: blood pressure variability, NT: normotension, MHT: masked hypertension, SHT: sustained hypertension.

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