The results of a randomised controlled trial published in The Lancet found that when GPs based medication adjustments on regular readings taken by patients at home, BP was significantly lower after 12 months compared with patients whose readings were taken in clinics. The use of self-monitoring did not increase GP workload, the researchers said.
The UK has much lower rates of BP self-monitoring than other countries. Internationally, surveys have found that up to 70% of people with hypertension self-monitor their BP from home, but in the UK it is around 30% of patients.
For this trial researchers from the Universities of Oxford, Cambridge and Birmingham recruited 1,003 patients aged over 35 with poorly-controlled blood pressure from 142 GP practices in England. They compared conventional care for BP management with two different forms of home monitoring - reporting BP readings via post (self-monitoring) or reporting results via text message (tele-monitoring).
Patients taking their readings at home were asked to monitor their BP twice each morning and evening for the first week of every month using an electronic BP monitor and report their readings to the clinic. Average systolic BP at the start of the trial was 153mmHg and average readings across the groups were compared at both six and 12 months.
After 12 months systolic BP was lower in both the self-monitoring (137.0mmHg) and tele-monitoring groups (136.0mmHg) compared with usual care (140.4mmHg).
'The differences between the interventions and control in systolic blood pressure would be expected to result in around a 20% reduction in stroke risk and 10% reduction in coronary heart disease risk,' the researchers said.
The researchers also found that BP became lower more quickly for those using the tele-monitoring system. After six months, systolic BP was on average 139.0mmHg in the tele-monitoring group, 140.4mmHg in the self-monitoring group and 142.5mmHg in those receiving usual care.
The tele-monitoring system automatically alerted patients if their reading was high, low or normal and provided text reminders to prompt patients to send their readings or contact the clinic if their medication needed adjusting. This system also enabled GPs to access a digital display of the BP readings and send messages to patients.
One of the barriers to more widespread adoption of home monitoring has been concern that patients may become anxious if asked to take their own BP measurements. However, this trial found no evidence of increased anxiety in patients who self-monitored or tele-monitored. There were also no changes in weight, diet, exercise or alcohol consumption that could have resulted in the BP reductions.
The target BP used in this trial was lower than previous self-monitoring trials to reflect evidence that BP readings are lower at home than in the clinic.
The researchers said that the 16m patients in the UK with hypertension should be offered the option of self-monitoring.
Lead author Professor Richard McManus, an Oxfordshire GP and NIHR professor of primary care at Oxford University’s Nuffield Department of Primary Care Health Sciences, said: ‘We now have conclusive evidence that GPs can use the readings from patients who self-monitor their own blood pressure to achieve significantly lower blood pressure after 12 months compared with conventional approaches.
‘This reduction in blood pressure comes with no additional workload for the GP, and the self-monitoring system is cheap and simple for patients to use. In the longer term we predict that better blood pressure control could result in significant health benefits for the patient – a likely 20% reduction in stroke risk and 10% reduction in coronary heart disease risk.
‘For faster, more efficient blood pressure reduction, using tele-monitoring could be worthwhile for some patients. Enabling the patient to text their readings to their GPs and nurses, with alerts and feedback for both patients and GPs, could be particularly advantageous in today’s NHS where doctors feel increasingly overwhelmed by the quantities of data they deal with on a daily basis.’