NIHR DC Discover

NIHR Signal Self-monitoring improves control of high blood pressure compared with GP monitoring alone

Published on 10 July 2018

doi: 10.3310/signal-000615

Allowing patients who have inadequately controlled high blood pressure to monitor their own blood pressure at home helps their GPs to optimise their management. Patients who self-monitor and visit or talk to their GP when needed for medication adjustments achieve 4mmHg lower systolic blood pressure over 12 months compared with those relying only on the measurements made by a GP without self-monitoring.

Effects are similar if patients write down their measurements to send to the GP or do so via a computerised system.

High blood pressure is a health priority because it increases the risk of serious conditions including stroke and heart disease. Many people with the condition are not achieving recommended blood pressure levels.

This NIHR funded study suggests that self-monitoring of blood pressure could help GPs titrate the dose of medication and could benefit patients through preventing stroke and heart disease

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Why was this study needed?

In England, high blood pressure affects more than 1 in 4 adults and increases their risk of diseases such as stroke and heart disease. It is estimated to cost the NHS over £2.1 billion each year.

For most people younger than 80 years, blood pressure is considered to be high if it is 140/90mmHg or more when measured in the clinic.

Only 35% of people in England with high blood pressure have been diagnosed and are achieving recommended blood pressure levels. Better ways to control their blood pressure could improve the situation for those diagnosed.

Previous studies where self-monitoring was used by GPs to help optimise drug treatment for high blood pressure had conflicting results.

What did this study do?

In this TASMINH4 trial, the authors randomised 1,182 adults with inadequately controlled high blood pressure to usual care or self-monitoring with or without telemonitoring.

Usual care patients had their blood pressure measured by their GP as often as the GP wished. With self-monitoring, participants measured their own blood pressure twice in the morning and twice in the evening for the first week of every month. They were told to see their GP if their blood pressure was very high or very low. GPs also reviewed measurements monthly.

With self-monitoring alone, participants wrote down results and posted them to the GP. With telemonitoring, participants sent their results by text to a GP-accessible computer system. It prompted them to see their GP if their blood pressure was very low or very high, or if average readings were above target. For all participants, GPs used blood pressure measurements to help them optimise drug treatment, aiming to achieve NICE’s recommended blood pressure targets.

The main outcome was blood pressure measured at the surgery by a research nurse. There were no important weaknesses in this study, so the results should be reliable.

What did it find?

  • After a year, using self-monitoring with or without telemonitoring reduced blood pressure compared with usual care, after taking into account baseline differences.
  • Self-monitoring alone reduced systolic blood pressure from baseline by 3.5mmHg more than usual care (95% confidence interval [CI] −5.8 to −1.2mmHg), and diastolic blood pressure by 1.5mmHg more (95% CI −2.7 to −0.2mmHg).
  • Self-monitoring plus telemonitoring reduced systolic blood pressure from baseline by 4.7mmHg more than usual care (95% CI −7.0 to −2.4mmHg), and diastolic blood pressure by 1.3mmHg more (95% CI −2.5 to −0.02mmHg).
  • Participants in all groups visited their GP a similar number of times. People in the self-monitoring groups were taking slightly more blood pressure medications on average than those in the usual care group. The defined daily dose, a standardised measure, was also higher in the group which used telemonitoring.
  • Side effects of blood pressure treatments appeared to be similar between the groups.

What does current guidance say on this issue?

NICE’s 2011 (updated 2016) hypertension guideline recommends that for people identified as having a ‘white coat effect’ (where blood pressure is higher in clinical settings than elsewhere) using home blood pressure monitoring in addition to clinic monitoring is an option. There are no recommendations on exactly what form home monitoring should take. The guideline recommended that more research should be carried out on whether out-of-office monitoring of blood pressure improved treatment response and patient outcomes.

NICE have stated that this guideline is being updated to include, among other things, ‘clearer guidance for home monitoring’ of blood pressure based on new evidence. The revised guideline is scheduled to be published in 2019.

What are the implications?

The findings suggest that self-monitoring is likely to be useful not just for patients who experience the ‘white coat effect’, but also those with uncontrolled high blood pressure.

While the extra reduction in blood pressure was relatively small, the authors estimate that it could reduce stroke risk by about 20%. This is in addition to the benefit from their standard GP care.

To determine whether investment in self-monitoring equipment and telemonitoring systems is justified, a cost-effectiveness analysis is being carried out using data from this trial. The results are likely to inform future guidance in this area.

Citation and Funding

McManus RJ, Mant J, Franssen M, et al; TASMINH4 investigators. Efficacy of self-monitored blood pressure, with or without telemonitoring, for titration of antihypertensive medication (TASMINH4): an unmasked randomised controlled trial. Lancet. 2018;391(10124):949-59.

This project was funded by the National Institute for Health Research Programme Grant for Applied Health Research (RP-PG-1209-10051), Oxford Collaboration for Leadership in Applied Health Research and Care, and Omron Healthcare UK (the manufacturer of the home blood pressure monitoring equipment used in the trial).

Bibliography

Ettehad D, Emdin CA, Kiran A, et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet. 2016;387(10022):957–67.

NICE. Hypertension in adults: diagnosis and management. CG127. London: National Institute for Health and Care Excellence; 2011, updated 2016.

Public Health England. Health matters: combating high blood pressure. London: Public Health England; 2017.

Why was this study needed?

In England, high blood pressure affects more than 1 in 4 adults and increases their risk of diseases such as stroke and heart disease. It is estimated to cost the NHS over £2.1 billion each year.

For most people younger than 80 years, blood pressure is considered to be high if it is 140/90mmHg or more when measured in the clinic.

Only 35% of people in England with high blood pressure have been diagnosed and are achieving recommended blood pressure levels. Better ways to control their blood pressure could improve the situation for those diagnosed.

Previous studies where self-monitoring was used by GPs to help optimise drug treatment for high blood pressure had conflicting results.

What did this study do?

In this TASMINH4 trial, the authors randomised 1,182 adults with inadequately controlled high blood pressure to usual care or self-monitoring with or without telemonitoring.

Usual care patients had their blood pressure measured by their GP as often as the GP wished. With self-monitoring, participants measured their own blood pressure twice in the morning and twice in the evening for the first week of every month. They were told to see their GP if their blood pressure was very high or very low. GPs also reviewed measurements monthly.

With self-monitoring alone, participants wrote down results and posted them to the GP. With telemonitoring, participants sent their results by text to a GP-accessible computer system. It prompted them to see their GP if their blood pressure was very low or very high, or if average readings were above target. For all participants, GPs used blood pressure measurements to help them optimise drug treatment, aiming to achieve NICE’s recommended blood pressure targets.

The main outcome was blood pressure measured at the surgery by a research nurse. There were no important weaknesses in this study, so the results should be reliable.

What did it find?

  • After a year, using self-monitoring with or without telemonitoring reduced blood pressure compared with usual care, after taking into account baseline differences.
  • Self-monitoring alone reduced systolic blood pressure from baseline by 3.5mmHg more than usual care (95% confidence interval [CI] −5.8 to −1.2mmHg), and diastolic blood pressure by 1.5mmHg more (95% CI −2.7 to −0.2mmHg).
  • Self-monitoring plus telemonitoring reduced systolic blood pressure from baseline by 4.7mmHg more than usual care (95% CI −7.0 to −2.4mmHg), and diastolic blood pressure by 1.3mmHg more (95% CI −2.5 to −0.02mmHg).
  • Participants in all groups visited their GP a similar number of times. People in the self-monitoring groups were taking slightly more blood pressure medications on average than those in the usual care group. The defined daily dose, a standardised measure, was also higher in the group which used telemonitoring.
  • Side effects of blood pressure treatments appeared to be similar between the groups.

What does current guidance say on this issue?

NICE’s 2011 (updated 2016) hypertension guideline recommends that for people identified as having a ‘white coat effect’ (where blood pressure is higher in clinical settings than elsewhere) using home blood pressure monitoring in addition to clinic monitoring is an option. There are no recommendations on exactly what form home monitoring should take. The guideline recommended that more research should be carried out on whether out-of-office monitoring of blood pressure improved treatment response and patient outcomes.

NICE have stated that this guideline is being updated to include, among other things, ‘clearer guidance for home monitoring’ of blood pressure based on new evidence. The revised guideline is scheduled to be published in 2019.

What are the implications?

The findings suggest that self-monitoring is likely to be useful not just for patients who experience the ‘white coat effect’, but also those with uncontrolled high blood pressure.

While the extra reduction in blood pressure was relatively small, the authors estimate that it could reduce stroke risk by about 20%. This is in addition to the benefit from their standard GP care.

To determine whether investment in self-monitoring equipment and telemonitoring systems is justified, a cost-effectiveness analysis is being carried out using data from this trial. The results are likely to inform future guidance in this area.

Citation and Funding

McManus RJ, Mant J, Franssen M, et al; TASMINH4 investigators. Efficacy of self-monitored blood pressure, with or without telemonitoring, for titration of antihypertensive medication (TASMINH4): an unmasked randomised controlled trial. Lancet. 2018;391(10124):949-59.

This project was funded by the National Institute for Health Research Programme Grant for Applied Health Research (RP-PG-1209-10051), Oxford Collaboration for Leadership in Applied Health Research and Care, and Omron Healthcare UK (the manufacturer of the home blood pressure monitoring equipment used in the trial).

Bibliography

Ettehad D, Emdin CA, Kiran A, et al. Blood pressure lowering for prevention of cardiovascular disease and death: a systematic review and meta-analysis. Lancet. 2016;387(10022):957–67.

NICE. Hypertension in adults: diagnosis and management. CG127. London: National Institute for Health and Care Excellence; 2011, updated 2016.

Public Health England. Health matters: combating high blood pressure. London: Public Health England; 2017.

Efficacy of self-monitored blood pressure, with or without telemonitoring, for titration of antihypertensive medication (TASMINH4): an unmasked randomised controlled trial

Published on 4 March 2018

McManus, R. J.,Mant, J.,Franssen, M.,Nickless, A.,Schwartz, C.,Hodgkinson, J.,Bradburn, P.,Farmer, A.,Grant, S.,Greenfield, S. M.,Heneghan, C.,Jowett, S.,Martin, U.,Milner, S.,Monahan, M.,Mort, S.,Ogburn, E.,Perera-Salazar, R.,Shah, S. A.,Yu, L. M.,Tarassenko, L.,Hobbs, F. D. R.

Lancet , 2018

BACKGROUND: Studies evaluating titration of antihypertensive medication using self-monitoring give contradictory findings and the precise place of telemonitoring over self-monitoring alone is unclear. The TASMINH4 trial aimed to assess the efficacy of self-monitored blood pressure, with or without telemonitoring, for antihypertensive titration in primary care, compared with usual care. METHODS: This study was a parallel randomised controlled trial done in 142 general practices in the UK, and included hypertensive patients older than 35 years, with blood pressure higher than 140/90 mm Hg, who were willing to self-monitor their blood pressure. Patients were randomly assigned (1:1:1) to self-monitoring blood pressure (self-montoring group), to self-monitoring blood pressure with telemonitoring (telemonitoring group), or to usual care (clinic blood pressure; usual care group). Randomisation was by a secure web-based system. Neither participants nor investigators were masked to group assignment. The primary outcome was clinic measured systolic blood pressure at 12 months from randomisation. Primary analysis was of available cases. The trial is registered with ISRCTN, number ISRCTN 83571366. FINDINGS: 1182 participants were randomly assigned to the self-monitoring group (n=395), the telemonitoring group (n=393), or the usual care group (n=394), of whom 1003 (85%) were included in the primary analysis. After 12 months, systolic blood pressure was lower in both intervention groups compared with usual care (self-monitoring, 137.0 [SD 16.7] mm Hg and telemonitoring, 136.0 [16.1] mm Hg vs usual care, 140.4 [16.5]; adjusted mean differences vs usual care: self-monitoring alone, -3.5 mm Hg [95% CI -5.8 to -1.2]; telemonitoring, -4.7 mm Hg [-7.0 to -2.4]). No difference between the self-monitoring and telemonitoring groups was recorded (adjusted mean difference -1.2 mm Hg [95% CI -3.5 to 1.2]). Results were similar in sensitivity analyses including multiple imputation. Adverse events were similar between all three groups. INTERPRETATION: Self-monitoring, with or without telemonitoring, when used by general practitioners to titrate antihypertensive medication in individuals with poorly controlled blood pressure, leads to significantly lower blood pressure than titration guided by clinic readings. With most general practitioners and many patients using self-monitoring, it could become the cornerstone of hypertension management in primary care. FUNDING: National Institute for Health Research via Programme Grant for Applied Health Research (RP-PG-1209-10051), Professorship to RJM (NIHR-RP-R2-12-015), Oxford Collaboration for Leadership in Applied Health Research and Care, and Omron Healthcare UK.

Systolic blood pressure is a person’s maximum blood pressure, reached when the heart muscle contracts (beats), measured in mmHg. This figure is the upper figure in the commonly used notation for blood pressure (systolic blood pressure/diastolic blood pressure).

Diastolic blood pressure is a person’s minimum blood pressure, reached when the heart muscle relaxes, measured in mmHg. This figure is the lower figure in the commonly used notation for blood pressure (systolic blood pressure/diastolic blood pressure).

Inadequately controlled high blood pressure: In this trial, this was considered to be a blood pressure of 140/90mmHg or higher despite taking (up to three) blood pressure medications.

Expert commentary

Self-monitoring of blood pressure is not a novel concept, yet we have only now observed its association with improved control compared with conventional monitoring strategies.

Empowering patients to actively manage their condition is particularly relevant for chronic diseases requiring lifelong engagement with treatment. Hypertension is no exception, and we can learn from other conditions. Would anybody in the diabetes community be surprised to hear that readings obtained by patients can meaningfully inform treatment decisions?

There remains potential for improvement in the management of hypertension, and it is conceivable that self-monitoring may translate to self-titration of medication in the future.

Christian Delles, Professor (Institute of Cardiovascular and Medical Sciences), University of Glasgow