Hypertension is a leading risk factor for cardiovascular disease. Despite effective medication the management of hypertension in primary remains suboptimal. Previous studies of self-monitoring, where patients monitor their own blood pressure and report back to their GP, have shown contradictory results in terms of effectiveness. The present 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.
The design of the trial was a three-arm parallel group with self-monitoring, with or without telemonitoring and compared to usual care. Eligible hypertensive patients were older than 35, with a blood pressure higher than 140/90 mm Hg and willing to self-monitor their blood pressure. The trial duration was 12 months.
Participants randomly assigned to self-monitoring were taught to use a validated automated electronic sphygmomanometer (Omron M10-IT). They were asked to monitor their own blood pressure in their non-dominant arm, twice each morning and evening, for the first week of every month using standard recommendations and their GPs were asked to use the self-monitored measurements for titration of antihypertensive medication. A simple colour chart was used to train participants to attend their practice for a blood pressure check as a result of very high or very low readings. At the end of each monitoring week they were asked to record their readings on paper and send them for review to their practice in a reply-paid envelope.
Participants in the telemonitoring group were asked to send their results via a simple SMS text service. The telemonitoring system incorporated an algorithm that alerted participants to contact their surgery in the light of very high or very low readings, reminded them if insufficient readings were transmitted, prompted them to make contact with their practice if their average blood pressure was above target, and presented readings to attending clinicians via a web interface. This secure web page automatically calculated mean blood pressure for each monitoring week, highlighted very high or very low readings, and presented a graphical display of blood pressure measurements.
General practitioners were asked to review both self-monitoring and telemonitoring groups’ readings on a monthly basis and usual care patients as often as they wished. Blood pressure targets were based on current National Guidelines adjusted for self-monitoring: lower than 140/90 mm Hg (<135/85 mm Hg at home) for those younger than 80 years, lower than 150/90 mm Hg (<145/85 mm Hg at home) for those 80 years or older, and lower than 140/80 mm Hg (<135/75 mm Hg at home) for those with diabetes.
A total of 142 general practices participated recruiting a total of 1182 participants, of which 1003 (85%) were included in the primary analysis.
Systolic blood pressure at baseline was around 153 mm Hg in all groups and at 12 months the blood pressure was lower in all of the groups, with the largest reduction seen in the self-monitoring and telemonitoring groups: blood pressure at 12 months, usual care group 140.4 (SD 16.5, n=348), self-monitoring group 137.0 (16.7, n=328), telemonitoring group 136.0 (16.1, n=327). At 12 months, the adjusted mean difference in systolic blood pressure compared to usual care was significantly lower for both the self-monitoring (-3.5 [95% CI -5.8 to -1.2] p=0.0029) and telemonitoring (-4.7 [-7.0 to -2.4] p<0.0001) groups. There was no difference in the adjusted mean difference between the self-monitoring and telemonitoring groups (-1.2 [-.3.5 to 1.2] p=0.3219).
After 12 months, the number of prescribed antihypertensives was higher in the self-monitoring (1.63 [SD 0.89]) and telemonitoring groups (1.70 [0.88]) compared to the usual care group (1.55 [0.85]). The adjusted mean difference was significantly higher in both the self-monitoring group (0.11 [95% CI 0.02 to 0.19] p=0.0129) and telemonitoring group (0.13 [0.04 to 0.21] p=0.0038) compared to the usual care group.
The authors conclude that after one year patients whose medication was adjusted using self-monitoring, with or without telemonitoring, has significantly lower systolic blood pressure than those receiving treatment adjusted using clinic blood pressure.
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