Response to “Repeatability of Different Segmental Pulse Wave Velocity Measurements”

To the Editor: We appreciate the thoughtful comments by Papaioannou and colleagues regarding our recently published article “Repeatability of Central and Peripheral Pulse Wave Velocity Measures: The Atherosclerosis Risk in Communities (ARIC) Study.” Numerous methods are used to evaluate repeatability of measurements and those chosen are influenced by the study question. Our interest was to examine the sources of variability in repeated measures at 2 time points using the intraclass correlation coefficient and SE of measurement. Repeatability could also be evaluated using the SD of differences and Bland–Altman method. The latter relies on a visual evaluation of plots to assess bias and whether the magnitude of differences between pairs of measures varies across the range of the mean. Since we used 1 device to obtain all measurements, we cannot speak to measurement-specific bias (other than from the literature).