Table 2.

Variability of BP and Arterial Stiffness for Baseline Results vs the First or Second Follow‐Up Visit

Characteristic	Baseline to First Follow‐Up (4669)					Baseline to Second Follow‐Up (10 823)
	ICC	CI	Cronbach α	Mean Increase	R 2	ICC	CI	Cronbach α	Mean Increase	R 2
Absolute values
SBP	0.67	0.66–0.68	0.80	1.28	0.45	0.58	0.57–0.58	0.74	2.55	0.34
DBP	0.63	0.62–0.64	0.78	−1.41	0.41	0.51	0.50–0.52	0.70	−2.89	0.30
PP	0.66	0.65–0.67	0.81	2.68	0.46	0.52	0.51–0.53	0.74	5.41	0.35
Arterial stiffness	0.21	0.18–0.24	0.38	0.66	0.05	0.18	0.16–0.20	0.33	0.50	0.04
No notch	0.22	0.12–0.32	0.36	0.04*	0.05	0.12	0.03–0.20	0.23	−0.92	0.02
Notched	0.30	0.27–0.33	0.48	0.52	0.10	0.26	0.24–0.28	0.42	0.53	0.07
By center	0.23	0.20–0.25	0.38	0.13*	0.05	0.18	0.17–0.20	0.33	0.31	0.04

The intraclass correlation coefficient (ICC), its CI, and Cronbach α are reported, with the mean increase from baseline to follow‐up and the R ² for a univariate linear regression. All analyses are significant at the P<0.001 level except for analyses with a *. BP indicates blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; SBP, systolic blood pressure.