Objective: Our previous study showed that post-clinic blood pressure (BP) taken 15 min after a physician-patient encounter was the lowest reading in a routine clinic. We aimed to validate this reading with 24 h Ambulatory Blood Pressure Monitoring (ABPM) readings. A cross-sectional study was conducted in the cardiology clinics at the Aga Khan University, Pakistan. Hypertensive patients aged ≥ 18 years, or those referred for the diagnosis of hypertension were included.
Results: Of 150 participants, 49% were males. 76% of all participants were hypertensive. Pre-clinic BP reading was measured by a nurse, in-clinic by a physician and 15 min post-clinic by a research assistant using a validated, automated BP device (Omron-HEM7221-E). All patients were referred for 24 h ABPM. Among the three readings taken during a clinic visit, mean (± SD) systolic BP (SBP) pre-clinic, in-clinic, and 15 min post-clinic were 153.2 ± 23, 152.3 ± 21, and 140.0 ± 18 mmHg, respectively. Mean (± SD) diastolic BP (DBP) taken pre-clinic, in-clinic and 15 min post-clinic were 83.5 ± 12, 90.9 ± 12, and 86.4 ± 11 mmHg respectively. Mean (± SD) daytime ambulatory SBP, DBP and pulse readings were 134.7 ± 15, 78.7 ± 15 mmHg, and 72.6 ± 12/min, respectively. Pearson correlation coefficients of pre-clinic, in-clinic and post-clinic SBP with daytime ambulatory-SBP were 0.4 (p value: < 0.001), 0.5 (p value: < 0.001) and 0.6 (p value: < 0.001), respectively. Post-clinic BP has a good correlation with ambulatory BP and may be considered a more reliable reading in the clinic setting.
Keywords: Ambulatory Blood Pressure Monitoring; Post-clinic blood pressure; White-coat effect.