Impact of repeated blood pressure measurement on blood pressure categorization in a population-based study from India

Often a single blood pressure (BP) measurement is used to diagnose and manage hypertension in busy clinics. However, repeated BP measurements have been shown to be more representative of the true BP status of the individual. Improper measurement of office BP can lead to inaccurate classification, overestimation of a patient's true BP, unnecessary treatment, and misinterpretation of the true prevalence of hypertension. There is no consensus among major guidelines on the number of recommended measurements at a single visit or the method of arriving at final clinic BP reading. 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. 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. There was a 63% higher prevalence of hypertension when only the first reading was considered for diagnosis in comparison to the mean of the second and third readings. 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. In those who are identified to have grade 1 or higher categories of hypertension, we recommend three BP measurements, with the mean of the second and third measurements being the clinic BP.