Validation of the custo screen 400 ambulatory blood pressure-monitoring device according to the European Society of Hypertension International Protocol revision 2010

Figures & data

Figure 1 Custo screen 400 test device.

Table 1 Screening and recruitment details

Screening and recruitment (n=37)
Total screened		37
Total excluded		4
Ranges complete	0
Range adjustment	2
Arrhythmias	0
Device failure	0
Poor-quality sounds	0
Cuff size unavailable	0
Observer disagreement	0
Distribution	2
Other reasons	0
Total recruited		33
	mmHg	All	On Rx
Recruitment ranges (n=33)
SBP
Low	<90 90–129	0 11	4
Medium	130–160 161–180	10 11	5
High	>180	1	8
DBP
Low	<40 40–79	0 11	5
Medium	80–100 101–130	11 11	5
High	>130	0	7

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; Rx, antihypertensive drug prescription.

Table 2 Subject characteristics at baseline

	Mean	SD	Min	Max
Sex
Male:female	13:20
Age (years)	57.4	13	25	87
Arm circumference (cm)	28.9	2.9	24	36
Cuff size for test device
Standard (24–32 cm), n (%)	31 (93.9)
Large (32–40 cm), n (%)	2 (6.1)
SBP (mmHg)	143.9	28.1	106	218
DBP (mmHg)	87.9	17.9	49	123

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation.

Table 3 Observer measurements for subjects within each BP range

	SBP (mmHg)	DBP (mmHg)
Overall range (low–high)	100–220	49–123
Low (SBP <130, DBP <80)	43	40
Medium (SBP 130–160, DBP 80–100)	30	34
High (SBP >160, DBP >100)	26	25
Maximum difference	17	15

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure.

Table 4 Observer differences

	SBP (mmHg)	DBP (mmHg)	Repeated measurements
Observer 2 – Observer 1
Range	−2 to 4	−4 to 4	NA
Mean (SD)	0.4 (1.4)	−0.4 (1.5)	NA

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation; NA, not applicable.

Table 5 Validation results

Part 1	≤5 mmHg	≤10 mmHg	≤15 mmHg	Grade 1	Mean (mmHg)	SD (mmHg)
Pass requirements
Two of	73	87	96
All of	65	81	93
Achieved
SBP	84	98	99	Passed	−0.5	4.5
DBP	93	99	99	Passed	−0.1	3.3
Part 2	2/3≤5 mmHg	0/3≤5 mmHg		Grade 2		Grade 3
Pass requirements	≥24	≤3
Achieved
SBP	30	0		Passed
DBP	32	1		Passed
Part 3						Result
						Passed

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation.

Figure 2 Bland–Altman plots demonstrating the systolic blood pressure (SBP) differences between the custo screen 400 device and reference sphygmomanometer and the average of device and observer pressure values.

Figure 3 Bland–Altman plots demonstrating the diastolic blood pressure (DBP) differences between the custo screen 400 device and reference sphygmomanometer and the average of device and observer pressure values.