Study conducted by PHFI, AIIMS, Economics and Planning Unit, Indian Statistical Institute
A study published recently in the Journal of Human Hypertension by researchers at 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, highlights the need for repeated measurements of blood pressure (BP) during a clinic or screening visit to reduce inaccurate classification of a patient’s true BP, resulting in wrong diagnosis and unnecessary treatments and its associated adverse effects. In current clinical practice (either due to large patient load or lack of awareness among physicians), often a single BP measurement is used to diagnose and manage hypertension in busy clinics. This results in a large number of patients being labelled as having high BP and often times receiving treatment that may not be needed. In this study the authors found a 63 per cent higher prevalence of hypertension when estimated through a single BP measurement as compared to an average of 2nd and 3rd BP measurement. The study also has important implications for the newly launched National Health Mission in India in which the Health and Wellness Centers (HWC) will play a pivotal role in non-communicable disease (NCD) detection and management. Hypertension detection and management will be an important activity of the HWCs.
Given the fact that BP measurement is one of the most common clinical practice tools used to determine heart health status as well as predict future heart health related events, the study highlights the need to do it correctly. The method used to arrive at a final clinic BP reading for an individual has implications at an individual as well as a population level. At an individual level, it plays a role in deciding the clinical management plan—to initiate anti-hypertensive medication in newly diagnosed individuals; intensify treatment in those with uncontrolled BP; or restrict to lifestyle modification advice in individuals who do not reach thresholds for drug therapy. At a population level, it helps estimate the prevalence of hypertension in the community accurately and has a role in determining public health priorities and health policy decisions.
In this large population based survey, the authors observed a large variation in prevalence of hypertension and the mean Systolic Blood Pressure (SBP) and Diastolic Blood Pressure (DBP) in single versus repeated BP recording. 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.
Dr Dorairaj Prabhakaran, Vice President, Research and Policy, PHFI and one of the authors of the study said, “There is a need to ensure accuracy in the diagnosis and management of hypertension. It is vital that clinical guidelines recommend uniform evidence-based methods of arriving at the final clinic BP. In our analysis, we observed considerable reclassification of individuals while using single versus repeated measurement for arriving at the final BP. However, the most important reclassification in terms of final management plan would be from those with high blood pressure needing treatment to optimal, normal, or high normal categories. Isolated single measurement increased the prevalence of hypertension by 63 per cent as compared to prevalence while using the mean of second and third reading . In this young population, based on a single BP measurement the prevalence of hypertension was 16.5 per cent and when the average of second and third readings were taken the prevalence reduced to 10.1 per cent. This large reduction in the number of people needing treatment has huge implications for the individual (in terms of avoiding unnecessary treatments) as well as the health system (by reducing the later footfalls to the hospitals as well as decreasing healthcare costs). Given that the community health workers, Accredited Social Health Activists (ASHAs) or NCD care coordinators are likely to measure BP initially, protocol guidelines should emphasise on 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.”
Dr Ambuj Roy, Professor, Department of Cardiology, AIIMS and author of the study said, “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. It is well known that BP varies from moment to moment with respiration, emotion, exercise, meals, tobacco, alcohol, ambient temperature, bladder distension, and pain. Medical practitioners must be encouraged to adopt the practice of repeated measurements in the same visit with the mean of the second and third measurements being 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 per cent of them got re-categorised as hypertensive based on multiple readings.”
The participants of the National Family Health Survey (NFHS-4), a nationwide survey conducted in India from 2015 to 2016, were used for the analysis of the study. The prevalence and median difference in systolic blood pressure (SBP) and diastolic blood pressure (DBP) for single as well as combinations of two or more readings were calculated. Cross-tabulation was used to assess classification of individuals based on first BP reading compared with the mean of two or more BP measurements. A decrease of 3.6 mmHg and 2.4 mm Hg in mean SBP and DBP, respectively, was observed when the mean of the second and third readings was compared to the first reading.