Reproducibility of masked hypertension among adults 30 years or older.
OBJECTIVE
Masked hypertension (MH) refers to nonelevated office blood pressure (BP) with elevated out-of-office BP, but its reproducibility has not been conclusively established. We examined 1-week reproducibility of MH by home BP monitoring (HBPM) and ambulatory BP monitoring (ABPM).


METHODS
We recruited 420 adults not on BP-lowering medication, with recent clinic BP between 120/80 and 149/95 mmHg. For main comparisons, participants with office average less than 140/90 mmHg were considered to have MH if awake ABPM average was 135/85 mmHg or higher; they were considered to have MH by HBPM if the average was 135/85 mmHg or higher. Percentage agreements were quantified in terms of κ. We also examined the prevalence of MH, defined as office average less than 140/90 mmHg, with a 24-h ABPM average of 130/80 mmHg or higher. We carried out sensitivity analyses using different threshold BP levels for ABPM-office pairings and HBPM-office pairings for defining MH.


RESULTS
Prevalence rates of MH based on office-awake ABPM pairings were 44 and 43%, with an agreement of 71% (κ=0.40; 95% confidence interval 0.31-0.49). MH was less prevalent (15 and 17%) using HBPM-office pairings, with agreement of 82% (κ=0.30; 95% confidence interval 0.16-0.44), and more prevalent when considering the 24-h average (50 and 48%). MH was also less prevalent when more stringent diagnostic criteria were applied. Office-HBPM pairings and office-awake ABPM pairings had fair agreement on MH classification on both occasions, with κ-values of 0.36 and 0.30.


CONCLUSIONS
MH has fair short-term reproducibility, providing further evidence that for some people, out-of-office BP is systematically higher than that measured in the office setting.
Departments of aFamily Medicine bMedicine - Division of Cardiology cPsychiatry, University of North Carolina School of Medicine dHypertension Research Program, University of North Carolina at Chapel Hill eDepartment of Biostatistics, University of North Carolina Gillings School of Global Public Health, Chapel Hill, North Carolina, USA.
Anthony J
AJ
Viera
Feng-Chang
FC
Lin
Laura A
LA
Tuttle
Emily
E
Olsson
Kristin
K
Stankevitz
Susan S
SS
Girdler
J Larry
JL
Klein
Alan L
AL
Hinderliter
D000328:Adult; D000367:Age Factors; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results