Evaluation of correlation between digital vs. mercury sphygmomanometer in a middle-income country: The role of socio-economic situation

Background Using manometer sphygmomanometers as standard measurement tool, there are controversial data regarding accuracy and validity of digital manometers for measurement of systolic (SBP) and diastolic blood pressure (DBP). Thus, we aimed to compare the accuracy of readings of digital sphygmomanometer in reference to mercury sphygmomanometer in a large population of healthy adults.Methods and Materials This cross-sectional study was performed on 1119 healthy adults. We measured participant’s blood pressure once with mercury sphygmomanometer, as gold standard and again with digital mercury sphygmomanometer. Blood pressure was measured in sitting position after 5 min of rest and preferentially from right arm unless deformed.Results The mean ± standard deviation of age of participants was 37.25 ± 10.45 years. Majority of participants were male 588 (52.5%). The right/left SBP measured by digital sphygmomanometer were significantly higher compared with those measured by mercury sphygmomanometer: 115.37 ± 12.33 vs 110.95 ± 10.06/113.69 ± 11.77 vs 110.23 ± 10.34, respectively (P < .001), while an opposite result was observed about right/left DBP: 68.60 ± 8.55 vs 70.60 ± 8.31/69.39 ± 8.31 vs 70.75 ± 8.41, respectively (P < .001). In subgroup analysis in terms of marital status, education, and income, we observed similar findings.Conclusion According to the results of our data analysis, it was shown that the digital device measurements had significant incompatibility with the mercury sphygmomanometers and it seems that digital devices still cannot be used as the gold standard in blood pressure measurement.