Background: Accurate measurement of blood pressure (BP) requires choosing an appropriate BP cuff size.
Objectives: The objective of this study was to examine the validity of regression equations to predict mid-arm circumference (mid-AC) using 2001-2012 National Health and Nutrition Examination Survey height and weight data.
Methods: National Health and Nutrition Examination Survey uses a complex multistage probability sample design to represent the civilian, noninstitutionalized US resident population. The sample consisted of 29 745 participants aged 20 years and older.
Results: For both men and women, the correlations between the predicted and measured mid-AC values were as follows: r=0.91 and 0.92, P<0.001, respectively. For both sexes, the difference between the predicted and measured mid-AC mean values was less than 1.5 cm. The overall percent agreement for selecting the appropriate BP cuff, using the American Heart Association cuff size criteria and comparing the predicted mid-AC values with measured values, was 83.0% for men and 80.0% for women. The percent agreement for small adult cuff was 10.0% for men and 54.0% for women; for adult cuff it was 87.0% for men and 88.0% for women; for large adult cuff it was 82.0% for men and 80.0% for women; and for thigh cuff it was 84.0% for men and 74.0% for women. All agreement statistics were above chance (for men, γ=0.96, and Kendall's Tau-b=0.73; for women, γ=0.97, and Kendall's Tau-b=0.76).
Conclusion: When possible, mid-AC should be directly measured for appropriate BP cuffing; however, the results of this validation study suggest that the prediction equations for mid-AC estimations were highly correlated and had an overall 80.0% agreement with measured mid-AC.