Validation of a Practical Approach to Blood Pressure Measurement: Secondary Analysis of Data from a Nationally Representative Survey in India.

Background: Clinical guidelines differ on the recommended number of blood pressure (BP) measurements for hypertension diagnosis in primary health care settings. We assessed the accuracy in identifying high BP (≥140/90 mmHg) and efficiency (mean BP measures per person in one visit) of a practical BP measurement approach against the research standard. Methods: We analyzed data from a national survey in India with three BP measurements for each adult participant (N = 372,110). The research standard (referred to as 'standard approach') is measuring three BP and using the mean of the last two. In the practical approach, the first BP reading was used if the measure was <140/90 mmHg; the second BP was used if the first BP was ≥140/90 mmHg. If the difference between either the first two systolic or diastolic BPs was >5 mmHg, then we used the third reading. Results: Prevalence of high BP was 15.5% and 14.9% using standard and practical approaches, respectively. The sensitivity, specificity, false positive, and false negative rates of the practical approach were 85.4%, 98.0%, 11.3%, and 2.7% compared to the standard approach. The practical approach was more resource-efficient (mean BPs/person/visit 1.4 versus 3.0 for the standard approach). The practical approach had similar validity, but higher efficiency compared to other internationally recommended BP measurement protocols. Conclusion: The practical BP measurement approach has high validity, is simpler and involves a lower measurement burden on health care providers and can improve the utility of BP measurement, hypertension diagnosis, and management in busy primary health care settings.