Simplifying the information letter in health research to fit the needs of low literacy participants: A Delphi consensus study - 02/11/26

Doi : 10.1016/j.jeph.2026.203817

Delvallée Marion ^1,^2,^{⁎
Delvallée M and Habchi O are co-first authors they contributed equally to this work}, Habchi Ouazna ^2,^{⁎
Delvallée M and Habchi O are co-first authors they contributed equally to this work}, Chenet Etienne ¹, Bravant Estelle ^1,², Drouin Pauline ², Dima Alexandra ^3,^4,^5,⁶, Schott Anne-Marie ^1,², Perrin Adèle ¹, Haesebaert Julie ^1,^2,^⁎
on behalf of the
DelphILIADE study group

¹ Research on Healthcare Performance RESHAPE, INSERM U1290, Université Claude Bernard Lyon 1, Lyon, France

² Hospices Civils de Lyon, Pôle Santé Publique, Service Recherche et Epidémiologie Cliniques, F-69003 Lyon, France

³ Avedis Donabedian Research Institute (FAD), C / Provença 293, Barcelona, Spain

⁴ Universitat Autònoma de Barcelona (UAB), Campus Bellaterra, Barcelona, Spain

⁵ Avaluació de tecnologies sanitàries en atenció primària i salut mental (PRISMA), Institut de Recerca Sant Joan de Déu (IRSJD), Santa Rosa 39-57, 08950, Esplugues de Llobregat, Spain

⁶ Consortium “Centro de Investigación Biomédica en Red” Epidemiology and Public Health (CIBERESP), Madrid, Spain

^# Corresponding author. RESHAPE Inserm U1290, 8 avenue Rockefeller, 69008 Lyon, France. Telephone: +33651429743 RESHAPE Inserm U1290, 8 avenue Rockefeller Lyon 69008 France

Sous presse. Manuscrit accepté. Disponible en ligne depuis le Monday 02 November 2026

Abstract

Background

Research participants must receive clear and accessible information to fully exercise their autonomy and make informed decisions about participating in clinical studies. However, information letters usually follow standard templates proposed by regulatory authorities that are unsuitable for participants with low health literacy levels. This study aimed to adapt the research information letter to participants with low health literacy level.

Methods

A 4 steps methodology was conducted: (1) assessment of the readability of the standard information letter, (2) development of a simplified version, (3) validation through a Delphi methodology involving 22 experts (researchers, IRB members, legal experts, and patients) and (4) test the information letter with low health literacy patients. The standard information letter was revised using methodological recommendations, communication tools and feedback from Delphi experts. The simplified information letter validate by Delphi experts was then tested with low health literacy patients using a teach back method.

Results

Readability scores of the standard information letter improved from university level (167 points) to a secondary level (98 points). Key adaptations included shortening sentences, adding a glossary, using pictograms, and simplifying legal language. The final IL was tested among 6 patients with low health literacy level, validating the understandability of the information letter.

Conclusions

This approach demonstrates that it is possible to create an information letter that is both understandable to low HL participants and compliant with regulatory standards.