Efficacy of open-label placebos for cardiac anxiety in inpatients with cardiovascular disease: A randomized controlled trial.

BACKGROUND

Open-label placebos (OLPs), administered transparently without deception, have shown beneficial effects in various settings, but evidence in inpatient clinical populations remains limited. This study investigated the efficacy of OLPs in reducing cardiac anxiety and related symptoms (sleep problems, lowered well-being) during cardiac rehabilitation.

METHODS

In this randomized controlled two-week trial, 122 inpatients (38% female; aged 40-83 years) were allocated to one of three groups: Treatment as usual (TAU), TAU plus self-monitoring, or TAU plus self-monitoring plus OLP. The OLP consisted of an orally administered water-based pump spray used twice daily. Primary outcomes were questionnaire-based assessments of cardiac anxiety, sleep quality, and well-being before and after the intervention. Secondary outcomes included daily symptom ratings, treatment expectancy and perceived efficacy, and adherence.

RESULTS

Across all groups, significant improvements were observed in cardiac anxiety, sleep quality, and well-being over time. However, there were no significant differences between groups for any primary outcome. Expected treatment efficacy at baseline was significantly higher than perceived efficacy at the end of the study. Adherence to self-monitoring was high and comparable between relevant groups.

CONCLUSIONS

OLP did not provide additional benefits beyond TAU and self-monitoring in improving cardiac anxiety, sleep quality, or well-being in an inpatient cardiac rehabilitation setting. These findings suggest that OLP effects may be limited in this specific clinical context characterized by structured and effective standard treatment.

TRIAL REGISTRATION: Trial was prospectively preregistered at the German Clinical Trials Register. URL: https://drks.de/search/en/trial/DRKS00036375.