Check BP thrice in same visit to prevent misdiagnosis, say experts

Findings of a study establish trend of inaccuracy in measuring blood pressure

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An estimated 46 million people in India have possibly been misdiagnosed of hypertension, and exposed to unnecessary treatment, according to a new study published in the Journal of Human Hypertension. 

Findings of the study establish the trend of inaccuracy in measuring blood pressure, resulting in a wrong diagnosis of high BP, unnecessary treatments and its associated adverse effects. Authors of the study belong to the Public Health Foundation of India (PHFI), All India Institute of Medical Sciences (AIIMS), New Delhi and the Economics and Planning Unit, Indian Statistical Institute.

The conclusion was reached via a large population-based survey—participants of the National Family Health Survey (NFHS-4), a nationwide survey conducted in India from 2015 to 2016— where the researchers observed a large variation in the prevalence of hypertension and the mean Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) when a single reading was taken, versus when the BP was recorded multiple times. “The median difference in SBP and DBP was observed to increase as measurements moved to higher BP categories, indicating the importance of repeating measurements especially in individuals with a high first BP reading,” they said in the journal article. 

Experts say that blood pressure varies depending on factors such as respiration, emotions, exercise, meals, tobacco, alcohol, ambient temperature, bladder distension and pain. “Medical practitioners must be encouraged to take repeated measurements in the same visit. The mean of the second and third measurements should be taken as the clinic BP, especially in patients with high blood pressure. This will prevent mismanagement and misdiagnosis of patients. In patients having normal BP, one reading maybe enough as only 0.2% of them got re-categorized as hypertensive based on multiple readings,” said Dr Ambuj Roy, Professor, Department of Cardiology, AIIMS, one of the authors of the study. Roy said that in India, most physicians rely on a single BP measurement “due to time constraints and in view of high clinical load in most health facilities”. However, in the study, the authors found that this was common in countries such as the USA as well.

The practice of taking a single reading results in a large number of patients being labelled as having high BP and, at times, receiving unnecessary treatment. Authors of the current study found a 63 per cent higher prevalence of hypertension when estimated through a single BP measurement as compared to an average of the second and the third BP measurement. 

Implications of the study would include not just patients in urban settings, but also those who are going to be screened at the government's Health and Wellness Centres (part of the centre's Ayushman Bharat scheme) in the rural areas. Detecting and managing hypertension is planned as an important activity of the wellness centres. According to data from the ministry of health and family welfare, over 17,000 centres have been launched across the country.

“In these centres, given that the community health workers, Accredited Social Health Activists (ASHAs) or non-communicable disease care coordinators are likely to measure BP initially, protocol guidelines should emphasize the importance of measuring BP thrice to prevent misdiagnosis and unnecessary commencement of hypertensive treatment in patients who only need to be encouraged to adopt a healthy lifestyle,” said Dr Dorairaj Prabhakaran, vice president, Research and Policy, PHFI.