Defining the hemodynamic response of hypertensive and normotensive subjects through serial timed blood pressure readings in the clinic

Abstract

Background: Every third patient in the clinic is misdiagnosed due to white-coat phenomenon, necessitating needless and costly treatment. We aimed to study the hemodynamic response of the physician's visit on hypertensive and normotensive patients by investigating the trend of blood pressure (BP) before, during and 15 min after the physician-patient encounter. Methods: A descriptive, cross-sectional study was conducted over a period of 8 months in the cardiology clinics at the Aga Khan University Hospital, Karachi. Both hypertensive and normotensive patients, aged ≥18 years, were recruited. Pregnant females or those with a history of volume loss were excluded. BP readings were taken using an automated, validated device (Omron-HEM7221-E) at three points: pre-clinic BP by the assessment nurse, in-clinic BP by the attending physician and post-clinic BP 15-min after the physician-patient encounter by a research assistant. Independent samples t-test was used to calculate the statistical difference between hypertensive and normotensive BP values. Results: Of 180 participants, 71% (n = 128) were hypertensive and 57% (n = 103) of all were males. The mean age of the participants was 57 ± 15 years. The mean and standard deviation(±SD) systolic BP (SBP) taken pre-clinic, in-clinic and 15-min post-clinic for hypertensive population was 128.7 ± 20 mmHg, 137.1 ± 21 mmHg and 127.9 ± 19 mmHg. The mean and standard deviation(±SD) SBP taken pre-clinic, in-clinic and 15 min post-clinic for normotensive population was 112 ± 16 mmHg, 115.8 ± 20 mmHg and 111.8 ± 15 mmHg. The hypertensive SBP values showed statistically significant difference from the normotensive values (difference in pre-clinic SBP: 16.7 mmHg, p-value < 0.001; in-clinic SBP: 21.3 mmHg, p-value < 0.001; and 15 min post-clinic: 16.1 mmHg, p-value < 0.001). Conclusions: Hypertensive and normotensive patients display congruent hemodynamics upon visiting the physician, the alert response being accentuated amongst the hypertensive group. In-clinic BP readings are higher for both hypertensive and normotensive patients making them unreliable for screening and management of hypertension amongst both the groups.