Do the Readings of Digital and Aneroid Sphygmomanometer Concur? A Clinic-Based Study in an Urban Area of South Kolkata

Abstract

Introduction: Hypertension is a major risk factor for cardiovascular and cerebrovascular diseases. Thus, regular and accurate measurement of Blood Pressure (BP) is essential for its early diagnosis and follow-up. There is a surge in popularity of digital sphygmomanometer due to its convenience of use and functionality. In contrast, the traditional universally accepted sphygmomanometer is aneroid type, hence there arise a need for comparison of digital and universally accepted Aneroid Sphygmomanometer in terms of agreement and correlation. Aim: To evaluate the agreement and correlation between blood pressure measurement by digital and aneroid sphygmomanometer. Materials and Methods: The clinic based cross-sectional study was conducted in the Out Patient Department (OPD) of Urban Heath Centre, All India Institute of Hygiene and Public Health, Kolkata, West Bengal, India. Adults visiting the OPD on two chosen days of the week, between June 2019 to July 2019 were selected using systematic random sampling. A total of 400 participants were included. Agreement and correlation between BP measurements by digital and aneroid sphygmomanometer was analysed by Cohen’s Kappa, Bland Altman Plot along with sensitivity, specificity and predictive values using Microsoft Excel and Statistical Package for the Social Sciences (SPSS) version 16.0. the p-value <0.05 was considered significant for the statistical test in the analysis. Results: Cohen’s Kappa value (0.59) revealed these two tools had moderate agreement in diagnosing hypertension. Sensitivity and specificity of digital sphygmomanometer taking aneroid sphygmomanometer as gold standard is 86% and 83.1% respectively. The BP readings of these two-tools showed moderate correlation as Intraclass Correlation Coefficient (ICC) for Systolic BP (SBP) and Diastolic BP (DBP) were 0.804 and 0.624, respectively. Bland Altman plot showed gross disagreement of SBP findings and disagreement between DBP findings was also noted. Conclusion: Digital device was found to be less accurate in detecting hypertension. Therefore, more similar research work is solicited to verify the accuracy of the very easy to use, the Digital BP monitor.