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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
People with high blood pressure are more likely to have their blood pressure controlled after 12 months if they self-monitor and receive counselling by telephone compared with usual monitoring in the clinic. When people were asked to self-monitor their blood pressure with no additional support, it was no better than getting their blood pressure measured in a clinic.
This NIHR-funded review of 25 trials found that self-monitoring with counselling by telephone reduced systolic blood pressure by about 6mmHg. Self-monitoring became less effective as the amount of healthcare support and education decreased.
It is not clear what the optimum frequency of checks is, but involving people in monitoring their condition is in line with NICE guidelines. The review did not look at the costs involved in providing the additional support. The accuracy and maintenance of home blood pressure machines also need to be taken into account, but the results look promising.
Why was this study needed?
More than one in four adults in England has high blood pressure. This is defined as more than 140/90mmHg on at least two occasions. High blood pressure increases the risk of cardiovascular diseases such as heart failure and stroke that cost the NHS over £2.1bn every year.
Lifestyle measures such as reducing salt in the diet, stopping smoking and regular exercise can reduce blood pressure. A stepped approach to adjust medication against blood pressure is also recommended. However, there can be issues with adherence to both of these treatment strategies.
This review explored whether people monitoring their own blood pressure reduced their levels over a year.
What did this study do?
This systematic review and meta-analysis included individual patient data from 25 randomised controlled trials of blood pressure self-monitoring for 10,487 people with hypertension. All studies were from high-income countries and six were from the UK.
The analysis compared usual care where blood pressure is regularly monitored in a clinic, with usual care plus self-monitoring. It also looked at whether different levels of professional support affected outcomes. The frequency of self-monitoring varied across studies from daily to monthly with most three times per week.
The studies were of reasonable quality with a low risk of bias. However, only 12 studies blinded assessors to participants’ groups. Additionally, there was wide variability between studies. These factors reduce our confidence in the size of this effect, but perhaps not its direction.
What did it find?
By 12 months:
- Overall, self-monitoring caused a small reduction in systolic blood pressure compared with usual care (mean difference [MD] ‑3.24mmHg, 95% confidence interval [CI] ‑4.92 to ‑1.57; 6,300 participants). It also slightly reduced diastolic blood pressure (MD ‑1.50mmHg, 95% CI ‑2.24 to ‑0.75, 6,300 participants).
- Self-monitoring reduced the risk of uncontrolled blood pressure by 30% compared with usual care (relative risk [RR] 0.70, 95% CI 0.56 to 0.86, 6,300 participants).
- Compared with usual care, self-monitoring plus telephone or other counselling was most effective at reducing systolic blood pressure (MD ‑6.10mmHg, 95% CI ‑9.02 to ‑3.18) and diastolic blood pressure (MD ‑2.32mmHg, 95% CI ‑4.04 to ‑0.59). It also reduced the risk of having uncontrolled blood pressure by 56% compared with usual care (RR 0.44, 95% CI 0.34 to 0.57).
- The next best combination was web/phone feedback with education. Web/phone feedback without education slightly reduced systolic blood pressure but did not reduce diastolic or uncontrolled blood pressure.
- Self-monitoring with no professional feedback did not reduce systolic, diastolic or uncontrolled blood pressure compared with usual clinic monitoring.
What does current guidance say on this issue?
The NICE 2016 guideline on managing hypertension in adults recommends people are encouraged to monitor their condition. It does not provide advice on whether to use a home blood pressure machine or how frequently to record measurements. An annual review is recommended for support and to assess medication. There is no specific guidance on more frequent counselling and support for home blood pressure measurements unless medication is being altered to get blood pressure under control.
What are the implications?
This review suggests that home blood pressure monitoring is better than usual clinic-based monitoring when accompanied by sufficient support. Understanding the costs involved would be important for commissioners considering implementing such a service.
It remains unclear how frequently the measurements need to be taken and if there are certain groups of people for whom it is more successful. The study does support the idea of giving people more control over their own health.
The researchers plan to analyse the data further to see if there is also an impact on outcomes such as stroke and quality of life.
Citation and Funding
Tucker KL, Sheppard JP, Stevens R, et al. Self-monitoring of blood pressure in hypertension: a systematic review and individual patient data meta-analysis. PLoS Med. 2017;14(9):e1002389.
This project was funded by the National Institute for Health Research School for Primary Care Research (NIHR SPCR number 112) and via an NIHR Professorship for Richard McManus (NIHR-RP-02-12-015).
Bibliography
NHS Choices. High blood pressure (hypertension): diagnosis. London: Department of Health; updated 2016.
NICE. Hypertension in adults: diagnosis and management. CG127. London: National Institute for Health and Care Excellence; 2016.
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