Primary care

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

Paul Little, MRC clinician scientist ^a, Jane Barnett, research nurse ^a, Lucy Barnsley, medical student ^a, Jean Marjoram, practice nurse ^b, Alex Fitzgerald-Barron, general practitioner ^c, David Mant, professor ^a. 

^aCommunity Clinical Sciences Division (Primary Medical Care Group), Faculty of Medicine, Health and Biological Sciences, Southampton University, Aldermoor Health Centre, Southampton SO16 5ST, ^b Nightingale Surgery, Greatwell Drive, Romsey SO51 7QN, ^c St Clements Surgery, Winchester SO23 8AD

Correspondence to: P Little psl3{at}soton.ac.uk

Primary care p 254

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

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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 =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 (r0.50) 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

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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.

	Acknowledgments

We thank the doctors, staff, and patients at Aldermoor Health Centre, Nightingale Surgery, and St Clements Surgery. We also thank Eoin O'Brien for advice and helpful comments. DM is now employed at the Division of Public Health and Primary Care, Institute of Health Sciences, Oxford OX3 7LF.

Contributors: PL and AFB had the original idea for the study. All authors contributed to the development of the protocol. JB, JM, and LB ran the study on a day to day basis. PL and LB performed the analysis. All authors contributed to writing the paper. PL is the guarantor of the study.

	Footnotes

Funding: NHS Regional Research and Development grant, and the HOPE charity. PL is funded by the Medical Research Council.

Competing interests: None declared.

	References

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1.	O'Brien E, Coats A, Owens P, Petrie J, Padfield P, Littler W, et al. Use and interpretation of ambulatory blood pressure monitoring: recommendations of the British Hypertension Society. BMJ 2000; 320: 1128-1134[Free Full Text].
2.	Cox JP, O'Malley K, O'Brien E. Ambulatory blood pressure measurement in general practice. Br J Gen Pract 1992; 42: 402-403[Web of Science][Medline].
3.	Webb DH, Stewart MJ, Padfield PL. Monitoring ambulatory blood pressure in general practice. BMJ 1992; 304: 1442.
4.	Beltman F, Heesen W, Smit A, May J, Lie K, Meyboom de Jong B. Acceptance and side effects of ambulatory blood pressure monitoring: evaluation of a new technology. J Hum Hypertens 1996; 10(suppl): s39-s42.
5.	Aylett M, Marples G, Jones K. Home blood pressure monitoring: its effect on the management of hypertension in general practice. Br J Gen Pract 1999; 49: 725-728[Web of Science][Medline].

(Accepted 21 March 2002)