Ratio of cuff width/arm circumference as a determinant of arterial blood pressure measurements in adults.

Recommendations state that the optimum ratio of blood pressure cuff width/arm circumference (CW/AC) is about 0.4. In this study of middle-aged men (n = 940) and women (n = 1484), we analysed the effect of CW/AC on blood pressure measurement variability and its interaction with age, body mass index (BMI), pulse rate and room temperature. In univariate polynomial regression, the variability (R2) in blood pressure that was explained by CW/AC was greater for women (systolic 6.3% and diastolic 5.7%) than for men (2.0% and 0.5%). In multivariate analysis the maximum variability explained independently by CW/AC was 2.7% for male and 6.7% for female systolic blood pressure, and 1.1% and 6.0% for male and female diastolic blood pressure, respectively. For systolic blood pressure this represented 10.4% of the explained variability in men and 9.3% of that in women. CW/AC is an important independent contributor to inter-individual variation in blood pressure measurement. It should therefore be taken into consideration in epidemiological studies and when medical care is being planned.