Poor adherence to home blood pressure measurement schedule

Consensus dictates that devices used for home blood pressure (BP) measurement should be equipped with a memory to store readings, rather than trusting patients' logbooks. However, data entered in the memory rely on patients' adherence to measurement schedules. We investigated the number and relevance of deviations from the requested measurement schedule.

We instructed 106 patients to perform 28 BP readings in a 2-week period with a memory-equipped electronic device. Patients were requested to note their scheduled BP values in their logbook and were not informed of the presence of a memory function.

The concordance between all BP recordings in both memory and logbook was 90.1% of possible total scheduled readings. The difference in mean BP of all readings from memory compared with all readings from the logbook was -0.06 mmHg (95% confidence interval -0.79 to 0.68) systolic and -0.28 mmHg (95% confidence interval -0.97 to 0.40) diastolic. Unscheduled measurements were performed by 57.5% of patients. Missing scheduled readings in both logbook and memory were found in 34.0% of patients. Fictional data were present for 16.0% of patients. When comparing all individual BP readings from the memory and the logbook, 10.4% of patients were classified in another hypertension stratum according to the European Society of Hypertension criteria. In 23.6% of patients, we did not find any bias.

In spite of the use of memory-equipped devices, to ensure patients' adherence to measurement schedules, patients still need proper instruction and a close watch.