Loaned self-measurement equipment model compared with ambulatory blood pressure monitoring

OBJECTIVE: To compare the correspondence between the loaned self-measurement equipment model (LSEM), 24 h awake ambulatory blood pressure monitoring (ABPM) and clinic blood pressure (CBP). DESIGN: A cross-sectional study was carried out involving 90 hypertensive and normotensive subjects. METHODS: We used a variation of home measurement, the loaned self-measurement equipment model (LSEM), that consisted of lending a number of sphygmomanometers, the property of the clinic, to patients for 3-day periods. The correspondence of results from LSEM was measured against the difference between the two averages, the correlation coefficients and the average unweighted absolute differences. RESULTS: The average difference between CBP and ABPM was 6.1/2.5 mmHg (P<0.001, r =0.54/0.63). Between CBP and LSEM, it was 6.6/1.4 mmHg (P<0.001/ 0.08, r =0.52/0.63), and between the ABPM and LSEM 0.5/-1.0 mmHg (P=0.70/0.14, r =0.71/0.75). The average unweighted absolute differences between LSEM and ABPM readings were 5.5 and 1.5 mmHg for systolic and diastolic blood pressure, respectively, whereas the average difference between CBP and ABPM means was much higher, at 6.8 mmHg for systolic and 2.7 mmHg for diastolic pressure. Agreement in the diagnosis of systolic hypertension between LSEM and ABPM was found in 78.8% of the individuals, and of diastolic hypertension in 76.7%. CONCLUSION: Blood pressure readings taken using LSEM have a better correspondence than CBP in predicting the awake ABPM value, although the disagreement in terms of diagnosing hypertension should be noted.