Diagnostic Comparability and Interchangeability Between Daytime Ambulatory Blood Pressure Monitoring and 24-Hour Ambulatory Blood Pressure Monitoring in Detecting Masked Hypertension

Background The primary aim of this study was to evaluate the level of diagnostic overlap between daytime ambulatory blood pressure (BP) monitoring (DT-ABPM) and 24-hour ambulatory BP monitoring (24-h ABPM) in detecting masked hypertension (MH). Methods This is a prospective study that was performed in a sample of 196 soldiers aged between 21 and 50 years (without a history of hypertension) undergoing ABPM testing. The diagnosis of MH based on DT-ABPM defined as (office blood pressure (OBP) <140/90 and DT-ABPM ≥135/85) was compared with the 24-h ABPM defined as (OBP <140/90 mm Hg and 24-h ABPM ≥130/80 mm Hg). We critically analyzed the results to see the agreement between the two methods. Results The number of subjects classified as having MH based on both DT-ABPM and 24-h ABPM, only on 24-h ABPM, and only on DT-ABPM were 11 (5.6%), 29 (14.8%), and 18 (9.2%), respectively. The sensitivity, specificity, and positive and negative predictive values for DT-ABPM in detecting MH were: sensitivity = 100% (95% CI: 97.82% - 100%), specificity = 62.07% (95% CI: 42.26% - 79.31%), PPV = 93.82% (95% CI: 90.50% - 96.03%), and NPV = 100%, respectively. The level of agreement between DT-ABPM and 24-h ABPM in diagnosing MH was 94.4% and discordance in 5.6% (11/196); (kappa=0.736, p < 0.001). Conclusion The sensitivity, specificity, positive and negative predictive values all showed agreement between the two BP methods to confirm the diagnoses of MH. DT-ABPM can be used as an alternative to the 24-h ABPM. DT-ABPM eliminates sleep disturbance attributable to ABPM and maximizes patient compliance with the ABPM test. A further larger trial is needed for more confirmation and to affect the guidelines for using daytime ABPM.