Comparison of acceptability of and preferences for different methods of measuring blood pressure in primary care

Blood pressure is probably the most common measurement used in clinical practice and the most common reason for initiation of long term treatment. Recent guidelines for the use of ambulatory monitoring of blood pressure recommend its use in both initial diagnosis (before starting treatment) and assessing control.¹ If ambulatory monitoring is to be used more often we need evidence about its acceptability. Anecdotal reports of its acceptability exist,²,³ and one large study found that the major drawback was sleep disturbance.⁴ It is not clear if patients regard such inconvenience and disturbance as worth while to obtain accurate readings or what patients feel about the alternatives. One study of home blood pressure monitoring suggested that patients found it acceptable.⁵ No study has yet explored the main issues for patients about the acceptability of the different methods of measuring blood pressure or compared the acceptability of all the available methods.

Methods and results

We recruited 200 patients from three practices; all had newly diagnosed essential hypertension or established hypertension with poor control. We measured blood pressure in all patients by repeated measurements by a nurse, home measurement, ambulatory monitoring, and measurement by a doctor. We also invited the final 70 patients to take their own blood pressure in a room provided in the practice (see p 000).

Two focus groups of patients who had experienced the different methods generated issues to be included in the questionnaire (table). Each group comprised seven or eight people, with a balance of younger (<60) and older patients, men and women, and manual and non-manual socioeconomic groups. A preliminary questionnaire to 60 consecutive patients confirmed that all the issues identified were felt to be important by most patients (except “knowing the blood pressure worries me”).

The overall mean “problem” score for each measurement (the mean item score) was internally reliable (Cronbach's α=0.85) and approximately normally distributed. We compared measurements by using analysis of variance for repeated measures and the Bonferroni correction for post hoc comparisons. We assessed the test-retest reliability after one month in 23 consecutive patients; 77% of the Spearman's r values for individual items were ⩾0.50, and no item performed badly (r⩽0.50) for more than two of the different methods of blood pressure measurement.

Patients felt that all methods were worth the trouble to get accurate measurements. Methods differed significantly in their overall “problem” score (ambulatory, home, doctor, and nurse (n=145), F=193, P<0.001; including self measurement in surgery (n=56) F=81, P<0.001). The scoring of ambulatory monitoring for discomfort and disturbance of life and sleep explains why its overall score (the mean of all the items) was significantly higher than those for the other methods. Home readings performed significantly better than all the other methods in the overall score and were also ranked highest by most patients.

Comment

The important issues identified in this study support the limited previous reports about the acceptability of various methods of blood pressure measurement.^2–5 Patients rated most methods as causing few problems and being worth the trouble to get accurate readings. Few patients regarded measurement by a doctor as the most acceptable method. Ambulatory monitoring performed less well than other methods, largely owing to discomfort and disturbance of life and sleep; there may be a trade off between the accuracy of ambulatory monitoring and its acceptability. Overall, home measurements may be the most promising option, as they are the most acceptable method to patients and were preferred to either readings in the surgery or ambulatory monitoring.

Table.

Rating of different methods of measuring blood pressure. Values are median (interquartile range) and mean unless stated otherwise

	Home (n=153)	Self measurement in surgery (n=63)	Ambulatory (n=156)	Nurse (n=153)	Doctor (n=152)
Disturbance and discomfort
It made me anxious	2 (2 to 5); 3.2	5 (2 to 5); 3.8	2 (2 to 5); 3.3	3 (2 to 5); 3.4	4 (2 to 5); 3.7
It disturbs home life or everyday activities	2 (2 to 5); 3.2	2 (2 to 4); 3.1	4 (2 to 5); 3.9	2 (2 to4); 3.0	2 (2 to 4); 3.0
It disturbs sleep	2 (2 to 4); 3.0	2 (2 to 4); 2.5	5 (2 to 6); 4.3	2 (2 to 4); 2.7	2 (2 to 4); 2.7
It disturbs work	3 (2 to 4); 3.1	3 (2 to 4); 3.2	4 (2 to 5); 4.0	4 (2 to 4); 3.3	3 (2 to 4); 3.2
I was uncomfortable	2 (2 to 4); 3.2	2 (2 to 3); 2.5	5 (2 to 6); 4.2	2 (2 to 3); 3.6	2 (2 to 3); 2.5
Self consciousness
I felt self conscious	2 (1 to 2); 2.3	2 (2 to 3); 2.6	2 (2 to 5); 3.2	2 (2 to 3.25); 2.5	2 (2 to 3.75); 2.6
Uncertainty
I felt unsure what to do	2 (1.25 to 2.75); 2.4	2 (2 to 3); 2.6	2 (2 to 2); 2.2	2 (2 to 4); 2.5	2 (2 to 3); 2.5
There is a lot of waiting around	2 (2 to 4); 2.8	2 (2 to 4); 2.7	2 (2 to 4); 2.9	2.5 (2 to 5); 3.3	4 (2 to 5); 3.7
It worried me knowing the blood pressure	2 (2 to 5); 2.9	2 (2 to 4); 2.7	2 (2 to 4); 2.8	2 (2 to 5); 3.0	2 (2 to 5); 3.0
It was difficult to remember to do it	2 (2 to 3); 2.6	2 (2 to 3); 2.5	2 (2 to 4); 2.4	2 (2 to 4); 2.6	2 (2 to 4); 2.5
Accuracy
It was worth the trouble to get accurate readings	6 (6 to7); 6.2	6 (6 to 7); 5.9	6 (6 to 7); 6.2	6 (6 to 7); 6.1	6 (6 to 7); 6.1
Control and efficiency
I felt in control	6 (6 to 6); 5.7	6 (5 to 6); 5.4	6 (4 to 6); 5.2	5 (4 to 6); 4.9	5 (4 to 6); 4.6
It is a good way to use or save doctor or nurse time	6 (6 to 7); 5.8	6 (6 to 7); 5.9	6 (6 to 7); 5.8	6 (4 to 6); 5.3	5 (4 to 6); 4.8
Analysis
Mean (SD) item score*	2.67 (0.90)	3.58 (0.48)	3.88 (0.82)	3.47 (0.70)	3.45 (0.79)
Difference in mean item score (95% CI) compared with ambulatory monitoring†	−1.28 (−1.10 to −1.46)	−0.41 (−0.18 to −0.65)	Not applicable	−0.45 (−0.31 to −0.59)	−0.48 (−0.34 to −0.61)
Ranking by patient‡	1 (1 to 2); 1.7	3 (2 to 4); 3.0	4 (2 to 4); 3.2	2 (2 to 3); 2.4	3 (2 to 3); 2.7
Rated as “best measurement for them” by patients (%)	67/154 (44)	2/52 (4)	27/154 (18)	36/154 (23)	16/154 (10)

Ratings: 1=disagree strongly; 2=disagree; 3=disagree slightly; 4=unsure or not applicable; 5=agree slightly; 6=agree; 7=agree strongly. 

^*Scoring reversed for positive items (control, good use of time, worth the trouble). 

^†Rank: 1=best, 2=next best, and so on. Self measurements in the surgery were ranked out of five possibilities; other measurements were ranked out of four (not including self measurement in surgery). ^‡Analysis of variance for repeated measures, using Bonferroni correction for multiple comparisons. 

Primary care p 254