Evaluation of the utility of unobserved office blood pressure measurement in a tertiary care centre

Abstract

Background: Recent guidelines emerging as a result of trials such as the SPRINT have started recommending out of office measurement to guide the clinician as office blood pressure measurements are subject to significant variation. Though currently not recommended for routine practice, unobserved blood pressure measurement is yet another method, which allows multiple measurements designed to remove several biases associated with the routine one – including errors, observer bias, and anxiety induced variations etc. Given the paucity of data on this modality, this study serves to address this important question-Whether a difference exists in recording the blood pressure unobserved?
Methods: A longitudinal study was done at JSS Hospital, Mysore, a 1800 bedded Medical college teaching hospital from February to April 2022. 120 consecutive consenting patients, of either sex of 18 to 85 years were enrolled in the study among those who met the inclusion criteria. Initially, after 2 minutes of rest in a comfortable chair, the doctors took two readings of BP & HR of the subjects two minutes apart using a validated instrument. Next, after 2 minutes of rest in a comfortable chair, a trained technician took two readings of BP & HR of the subjects two minutes apart using the same validated instrument. Then, the subjects were led by the trained technician to a specially designated quiet room. After a period of rest for 10 minutes, BP and HR were measured at ‘0’ minute and subsequently at 10th, 12th, and 14th minutes, unobserved.
Results: In the study, 57.5% were males and 42.5% were females. Mean age of subjects was 59.03 ± 13.20 years. The mean unobserved SBP was 137.09 ± 18.15 mmHg and observed SBP was 151.84 ± 18.36 mmHg. There was significant difference in mean SBP between Unobserved and observed readings. (p<0.001) Mean unobserved DBP was 83.08 ± 9.91 mmHg and observed SBP was 88.01 ± 10.68 mmHg. There was significant difference in mean DBP between Unobserved and observed readings. (p<0.001)
Conclusion: There was a significant statistical variation in the blood pressure measurement when the subject is not under observation and when measured under observation by the Physician or technician. Hence before diagnosing the person as “Hypertensive”, detailed evaluation of Blood Pressure with and without observation needs to be done.