Only few studies have compared attended and unattendd BP measurements; none of them implemented the approach for unattended BP measurement used in SPRINT study by the use of completely automated device for both attended and unattended BP and by the measurement of 3 values after 5 minutes of rest,.
In 261 consecutive outpatients attending the outpatient clinic at an ESH Excellence Centre, BP values were measured by the physician with an automated oscillometric device (Omron HEM 9000Ai, mean of 3 measurements), after 5 minutes of rest. Thereafter the patient was left alone in the room, and the device was programmed to automatically perform 3 BP measurements.
Mean age was 61 ± 16 yrs, 60%, BMI 26.1 ± 4.2, 88 % with a previous diagnosis of hypertension (64 % treated). Unattended systolic BP (SBP) and diastolic BP (DBP) were lower as compared to attended SBP (130.1 ± 15.7vs138.6 ± 17.2 mmHg) and DBP (77.1 ± 11.7vs78.9 ± 12.2 mmHg). The differences (Δ) between the values obtained using the two techniques were 8.5 ± 7.9 mmHg for SBP and 1.8 ± 5.6 mmHg for DBP. Δ SBP was directly correlated with age (r = 0.235 p < 0001) and with attended BP values (r = 0.407 p < 0.0001); Δ SBP was significantly lower in males than in females. At multivariate analysis Δ SBP remained independently related with age and attended SBP. Δ DBP was related with attended DBP (r = 0,322 p < 0.001) and was lower in males.
Our findings indicate that “unattended BP” measurement provides values significantly lower as compared to measurements obtained in the presence of the physician. Interestingly, the difference between the values obtained by the two approaches is not constant for all patients, being significantly affected by age, gender and BP values.