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PREVALENCE OF MASKED AND WHITE COAT HYPERTENSION IN A LARGE 24HR AMBULATORY BLOOD PRESSURE MONITORING POPULATON

PREVALENCE OF MASKED AND WHITE COAT HYPERTENSION IN A LARGE 24HR AMBULATORY BLOOD PRESSURE MONITORING POPULATON

 

D.W. ARMSTRONG (1), M.F. MATANGI (1)

(1) KINGSTON HEART CLINIC, KINGSTON-CANADA,

 

OBJECTIVE. To define the prevalence of masked hypertension and white coat hypertension in patients presenting for 24hr ambulatory blood pressure monitoring (ABPM).
DESIGN. Data from 15,069 ABPMs performed over a period of 9 years were entered into our database, CARDIOfile. We have confined our analysis to systolic blood pressure (SBP). We compared office SBP with mean 24hr SBP. We defined normotensive as office SBP ≤140mmHg or mean 24hr SBP ≤130mmHg. Masked hypertension was defined as office SBP ≤140mmHg with a mean 24hr SBP of >130mmHg. White coat hypertension was defined as office SBP >140mmHg and a mean 24hr SBP of ≤130mmHg.
METHODS. Data were analyzed using Student's t-test and linear regression analysis. A p value of <0.05 was considered significant.
RESULTS. The mean office and mean 24hr ABPM SBPs (mmHg) for the 15, 069 recordings were, 153.3± 18.1 and 132.3±13.7 respectively, (P<0.0001). Using linear regression analysis the r value between the two measurements was 0.67 (P<0.0001).  The distribution of results is seen in the table below.
CONCLUSIONS. The overall prevalence of masked hypertension and white coat hypertension was 3% and 33% respectively. The results are for patients both with and without antihypertensive drug therapy.

Category.

N

%

Hypertensive.

7,333

48

White coat hypertensive.

4,920

33

Normotensive.

2,421

16

Masked hypertensive.

395

3

Total.

15,069

100