COLOUR COAT

Rationale:
The white coat effect is a well-documented clinical phenomenon, characterized by elevated blood pressure readings observed in medical settings, whereas measurements taken in non-clinical environments tend to be lower. Its prevalence varies across studies, but is estimated to affect approximately 15–50% of the general population. This phenomenon has been linked to an increased likelihood of developing sustained hypertension over time and may be associated with a slightly heightened risk of cardiovascular events and target organ damage when compared to individuals with consistently normal blood pressure.
Despite the established correlation between clinical settings and these transient hypertensive responses, the underlying cause remains uncertain. It is not yet fully understood whether this effect stems from the colour of the coat itself, its symbolic significance, the clinical environment as a whole, or the anxiety provoked by the act of being monitored.
Therefore, we investigated whether the colour of a doctor’s coat has an effect on blood pressure compared to the traditional white coat. In contrast to the traditional white coat, we propose a blue coat, rainbow coat and red Santa coat as possible alternatives, resembling potentially calming colours, more diverse colours and seasonal colours respectively.

Goal:
To assess the effect of coat colour on non-invasive blood pressure and to explore whether a more diverse and inclusive colour (palette) should be chosen as an alternative.

Study design:
Randomised controlled trial, four arms (White coat, Blue coat, Rainbow coat and Red Santa coat)

Study population:
Participants aged 24 years or older who are not active patients at the hospital

Exclusion criteria:
refusal of participation / informed consent

Number of patients needed:
200

Primary endpoint:
Change in Mean Arterial Pressure, Systolic Blood Pressure and Diastolic Blood Pressure from baseline (grey attire) to intervention (coloured coats), compared across coat colours (averaged measurements of 2nd and 3rd measurement for both baseline and intervention time points)

Secondary endpoint:
Heart rate (averaged measurements of 2nd and 3rd measurement for both baseline and intervention time points)

Statistical Analyses:
Data, registered in CASTOR, will be analysed using STATA 17.0 SE (StataCorp, College Station, TX, USA). The primary analysis will be perfomed using one-way analysis of variance (ANOVA) to compare the change in blood pressure (defined as post-intervention minus baseline values) across the four coat colour groups. For secondary analyses, linear mixed-effects models will be applied.

Date of idea:
19-01-2025

Date of final realization of protocol:
27-03-2025

Date of start measurements:
1-04-2025

Date of last measurements:
1-07-2025