Efficacy of Self-Monitored Blood Pressure, with or without Telemonitoring, for Titration of Antihypertensive Medication (TASMINH4)

Clinical Question

In patients with uncontrolled hypertension requiring blood pressure monitoring, does self-monitoring at home result in lower blood pressure readings than office monitoring alone?

Bottom Line

In patients with poorly controlled blood pressure, self-monitoring, with or without telemonitoring, used by practitioners to titrate antihypertensive medication leads to significantly lower blood pressure as compared to titration guided by clinical readings alone.

Major Points

This study was conducted in order to assess the significance of monitoring blood pressure elsewhere other than at office visits alone. This in turn could lead to better controlled blood pressure in larger populations. The population for the study included patients older than 35 with uncontrolled hypertension taking no more than three hypertensive agents. The intervention included either self-monitoring alone or self-monitoring along with telemonitoring. These groups were then compared to a control group that monitored blood pressure at physician offices alone. The primary outcome used was the systolic blood pressure that was measured at 12 months and was adjusted for baseline covariates. TASMINH4 sought to compare the lowering of blood pressure in three groups; a self-monitoring group, a self-monitoring with telemonitoring group, and a usual care group. Blood pressures were measured at baseline and again at 6 and 12 months. At 6 months, the telemonitoring group was statistically lower with a SBP p value of 0.0012 and DBP p value of 0.0482. At 12 months, both the telemonitoring and self-monitoring groups were statistically lower with SBP p values of <0.0001, 0.0029 respectively, and DBP p values of 0.0482, 0.0209 respectively.

Design

• Un-Masked Randomized Control Trial
• N=(1182)
  • Self-Monitoring (n=395)
  • Self-Monitoring with Telemonitoring (n=393)
  • Standard (n=394)
• Setting: This study took place over 142 general practices in the UK.
• Enrollment: January to June 2001, February 2003 to October 2005
• Follow-up: 6 and 12 months
• Analysis: Intention-to-treat
• Primary outcome: Average mean difference (AMD) in systolic blood pressure measurements at 12 months.

Population

Inclusion Criteria

• Older than 35 years
• Diagnosed with HTN under the clinical guidelines 127 of the NICE in the UK
• Taking no more than three hypertensive agents
• BP greater than 140/90 mmHg
• Willing to self-monitor BP
• On stable antihypertensive medication for at least 4 weeks prior to randomization

Exclusion Criteria

• Orthostatic hypertension/hypotension
• AFib
• Dementia
• CKD of grade 4 or worse
• CKD with proteinuria

Baseline Characteristics

• Male 53%
• 67 years-old on average
• White ethnicity 95%
• Average BMI of 29.3
• Married or cohabiting 76%
• Most retired at 76%
• 63% reported having “other ongoing problems” aside from the other categories of CKD, MI, coronary artery bypass, etc., stroke or diabetes (2nd highest at 9%)

Interventions

• All participants attended their own General Practitioner for a review of his/her medications.
• Attending clinicians were capable of altering anti-hypertensive medications regardless of assigned group and to his/her discretion.
• All participants followed up at 6 and 12 months by research nurses. Participants were randomly assigned to one of three groups:
• Self monitoring groups: Participants were taught how to use a specified at home blood pressure monitoring device.
• Self-monitoring groups: Participants monitored blood pressure in the non-dominant arm twice each morning, and twice each evening for the first week of the month, every month. Attending clinicians reviewed both self-monitoring groups’ monthly.
• Self monitoring alone: Participants wrote down blood pressure values on paper and mailed them in a pre-paid envelope to the provider.
• General Practitioners of the self-monitoring group used self-monitored blood pressure values for anti-hypertensive medication titration.
• Self monitoring with Telemonitoring: Participants were trained to use SMS texting to send blood pressure values.
• Self monitoring with Telemonitoring: Aweb-based algorithm communicated with the participant if blood pressure readings were low, high, or insufficient and presented this recorded information with attending clinicians on the web interface.
• Self monitoring with Telemonitoring: Mean blood pressure values were automatically calculated by this program for each monitoring week and provided a graphical display of blood pressure values.
• Usual care: The usual care group was monitored as often as the physician desired.
• Usual care patient’s anti-hypertensive medications were titrated at 6 and 12 months based on blood pressure measurements from clinic.
• Usual care: Adjustments of antihypertensives done by the general practitioners were unrestricted in terms of frequency and drug used.

Outcomes

Comparisons are intensive therapy vs. standard therapy.

Primary Outcomes

Mean Systolic Blood Pressure at 12 months was significantly lower in both the self-monitoring and telemonitoring intervention groups compared with usual care group (clinic monitoring).

Self-monitoring AMD -3·5 mm Hg (95% CI: -5·8 to -1·2), p=0·0029, Telemonitoring AMD -4·7 mm Hg (95% CI: -7·0 to -2·4), p<0·0001

Secondary Outcomes

Systolic blood pressure measurements at 6 months in clinic were significantly lower in the telemonitoring group, but not significantly different in the self-monitoring group, compared to the usual care group.

Telemonitoring AMD -3·7 mm Hg (95% CI:-5·9 to -1·5), p=0·0012, Self-monitoring AMD -2·1 mm Hg (95% CI:-4·3 to 0·1), p=0·0584

Diastolic blood pressure in the telemonitoring group at 6 months was significantly lower compared to baseline, but not the self-monitoring or usual care groups. There was no significant difference between the two intervention groups.

Telemonitoring AMD -3·7 mm Hg (95% CI: -5·9 to -1·5), p=0·0012, Self-monitoring AMD -2·1 mm Hg (95% CI:-4·3 to 0·1), p=0·0584, Telemonitoring vs. self-monitoring; AMD -1·5 mm Hg (95% CI:-3·8 to 0·7) p=0·1771

Antihypertensive medication prescription number was significantly higher self-monitoring and telemonitoring individuals after 12 months compared to those in the usual care group.

Self-monitoring had an AMD of 0·11 (95% CI: 0·02 to 0·19) more medications (p=0·0129) compared with usual care, Telemonitoring had an AMD of 0·13 (95% CI: 0·04 to 0·21) more medications (p=0·0038) compared with usual care

Defined daily doses (DDD) were significantly increased at 12 months in individuals using telemonitoring, but not self-monitoring compared to the usual group.

Telemonitoring DDD AMD 0·31 (95% CI: 0·15 to 0·47), p<0·0001 compared with usual care., Self-monitoring DDD AMD 0·19 (95% CI: 0·03 to 0·36), p=0·0175, compared with usual care.

Subgroup Analysis

Self-monitoring vs usual care: age, female sex, standard BP target group, no history of CV disease = significant Favoring self-monitoring with a 95% CI (-5.83 to -1.20) and a p value of 0.0029

Telemonitoring vs usual care: Age, sex, standard BP target group, IMD score, no history of CV disease = significant Favoring telemonitoring with a 95% CI (-7.02 to -2.39) and a p value of <0.0001

Adverse Events

Dry mouth Self-monitoring vs Usual care: 27% vs 19% (p=0.0036) Telemonitoring vs Self-monitoring: 22% vs 27%; CI (0.24 to 0.89)

Criticisms

• Investigators were not blinded.
• Most participants were white of British ethnicity. Ideally we would want a more diverse ethnicity so it could be applied to a bigger population.
• Since the telemonitoring group received multiple alerts such as reminders and prompts, this may have provided them with extra motivation that the other groups did not have.
• The usual care group did not have a set time interval which blood pressure would be assessed and medications by clinicians; whereas the self-monitoring and telemonitoring groups had a monthly review by physicians.
• White Coat hypertension is a factor that should be considered when evaluating the blood pressure of the usual care group.