Why the study?
Results from blood pressure control interventional trials must be interpreted cautiously, motivating an analysis to deconstruct observed drops in systolic blood pressure into components such as increased adherence, regression to the mean, and initiation of new medications.
Does enrollment in a research study and self-measurement of blood pressure reduce systolic blood pressure through a Hawthorne effect in patients with uncontrolled blood pressure?
Population
Smartphone-owning patients with uncontrolled BP > 145 mmHg wishing to lower BP by > 10 mmHg
Comparison
One of two devices for self-measurement of BP
Design
Secondary analysis of a pragmatic randomized controlled trial
Follow-up
Up to 24 months
Key result
Enrollment in a blood pressure trial resulted in an immediate systolic blood pressure drop of -4.2 mmHg (95% CI, -5.1 to -3.3; p<0.001) due to increased adherence to pre-existing medications.
Authors
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BP trial SBP reductions may partly reflect adherence gains and regression to the mean; supports adjusted analyses in future intervention studies.
RCT
randomly assigned
Does enrollment in a research study and self-measurement of blood pressure reduce systolic blood pressure through a Hawthorne effect in patients with uncontrolled blood pressure?
Effect estimate: Mean drop -4.2 mmHg (95% CI -5.1 to -3.3)
p-value: p=<0.001
A significant portion of blood pressure reductions observed in clinical trials may be attributable to the Hawthorne effect (increased adherence due to study enrollment) and regression to the mean, rather than the specific intervention being tested.
Rosen et al. (2026) conducted an RCT in Uncontrolled blood pressure. Self-measurement of BP devices was evaluated on EHR-recorded office SBP (Mean drop -4.2 mmHg, 95% CI -5.1 to -3.3, p=<0.001). Enrollment in a blood pressure trial resulted in an immediate systolic blood pressure drop of -4.2 mmHg (95% CI, -5.1 to -3.3; p<0.001) due to increased adherence to pre-existing medications.