Table 3.

Mean absolute error compared with reference device and failure rate of monitors (n = 327) by frequency of use^a

Frequency of use	Monitors, n	Failing monitors, n (%)b	MAE, mmHg (95% CI)
>10 times a month	27	3 (11)	0.89 (0.84 to 0.94)
6–10 times a month	41	2 (5)	0.74 (0.69 to 0.78)
1–5 times a month	115	12 (10)	0.86 (0.84 to 0.89)
6–11 times a year	57	13 (23)	1.08 (1.04 to 1.11)
1–5 times a year	44	10 (23)	0.96 (0.92 to 1.00)
Less frequently	28	5 (18)	0.94 (0.88 to 0.99)
Not stated	15	1 (7)	0.67 (0.60 to 0.74)

^aFour monitors could not be tested fully but should be counted as failures.

^bPercentage of total monitors per frequency-of-use classification. CI = confidence interval. MAE = mean absolute error.