Table 3.

Reproducibility of total sleep time, mean ambulatory blood pressure, nighttime blood pressure dipping, and ambulatory blood pressure categories between ambulatory blood pressure monitoring periods 1 and 2 using times derived from self-report, fixed-time periods^† and actigraphy (analysis of 330 paired ABPM assessments in 330 participants).

	Comparing ambulatory blood pressure monitoring period 1 and 2
	Self-reported	Fixed-time	Actigraphy
Number of participants	(n=330)	(n=330)	(n=330)
	Intra-class correlation coefficient (95% confidence interval)‡
Total sleep time	0.46 (0.37 – 0.54)	–	0.29 (0.20 – 0.39)*
Mean ambulatory systolic blood pressure
Daytime	0.79 (0.75 – 0.83)	0.76 (0.72 – 0.81)	0.81 (0.77 – 0.85)
Nighttime	0.77 (0.72 – 0.81)	0.75 (0.70 – 0.79)	0.77 (0.72 – 0.81)
Mean ambulatory diastolic blood pressure
Daytime	0.79 (0.75 – 0.83)*	0.76 (0.72 – 0.81)	0.81 (0.77 – 0.85)*
Nighttime	0.77 (0.72 – 0.81)	0.76 (0.71 – 0.80)	0.78 (0.73 – 0.82)
Nighttime blood pressure dipping	0.43 (0.34 – 0.58)**	0.43 (0.35 – 0.52)	0.44 (0.35 – 0.52)**
	Kappa statistic (95% confidence interval)‡
Daytime hypertension	0.65 (0.54 – 0.76)	0.54 (0.43 – 0.65)	0.63 (0.52 – 0.74)
Nighttime hypertension	0.64 (0.54 – 0.73)	0.61 (0.52 – 0.70)	0.62 (0.53 – 0.72)
Non-dipping status (2-groups)	0.40 (0.30 – 0.50)	0.36 (0.26 – 0.47)	0.36 (0.25 – 0.46)
Magnitude of dipping status (4-groups)††	0.32 (0.24 – 0.40)	0.30 (0.22 – 0.38)	0.28 (0.20 – 0.37)

Daytime hypertension is defined as daytime systolic ≥135 mmHg or diastolic blood pressure ≥85 mmHg (yes/no).

Nighttime hypertension is defined as a nighttime systolic ≥120 mmHg or diastolic blood pressure ≥70 mmHg (yes/no).

Non-dipping status defined as a dichotomous outcome (yes/no; non-dipping status if mean night-day BP ratio is >0.90).

Magnitude of dipping defined as 4 categories: extreme dipper (mean night-day BP ratio ≤0.80), dipper (mean night-day BP ratio >0.80 and ≤0.90), non-dipper (mean night-day BP ratio >0.90 and ≤1.00), and reverse dipper (mean night-day BP ratio >1.00).

^*Indicates p-value ≤0.05 using McNemar’s chi-square test for paired proportions or paired t-test as appropriate.

^**Indicates p-value ≤0.01 using McNemar’s chi-square test for paired proportions or paired t-test as appropriate.

^†Using the definition of the International Database of Ambulatory Blood Pressure in relation to Cardiovascular Outcome (IDACO) for Europeans (nighttime: 00:00 to 06:00; daytime: 10:00 to 20:00).

^‡Intra-class correlation coefficient or Cohen’s Kappa statistic Test of agreement for continuous or categorical variables, respectively.

^††Weighted Kappa for categorical variables with greater than 2 levels.[19]