Are stroke patients' reports of home blood pressure readings reliable? Cross-sectional study

Objective. To assess the reliability of home BP recording in hypertensive patients who had suffered a recent stroke or transient ischaemic attack. Methods. Thirty-nine stroke patients (mean age 73 years) randomized to the intervention arm of a trial of home BP monitoring were included. Following instruction by a research nurse, patients recorded their BPs at home and documented them in a booklet over the next year. The booklet readings over a month were compared with the actual readings downloaded from the BP monitor and were checked for errors or selective bias in recording. Results. A total of 1027 monitor and 716 booklet readings were recorded. Ninety per cent of booklet recordings were exactly the same as the BP monitor readings. Average booklet readings were 0.6 mmHg systolic [95% confidence interval (95% CI) -0.6 to 1.8] and 0.3 mmHg diastolic (95% CI -0.3 to 0.8) lower than those on the monitor. Conclusions. This group of elderly stroke patients were able to record their BPs reliably at home. Any bias was small and would be unlikely to affect management. Since BP readings in a GP surgery are often a poor indication of true BP, GPs might consider using hypertensive patients' records of home BP monitoring to help guide treatment decisions.