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PLoS One. 2019 Aug 13;14(8):e0220383. doi: 10.1371/journal.pone.0220383. eCollection 2019.

What do adult outpatients included in clinical trials know about the investigational drugs being assessed: A cross-sectional study in France.

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Department of Pharmacy, Nantes University Hospital, Nantes, France.
Department of Pharmacy, Reims University Hospital, Reims, France.
Department of Pharmacy, Orléans Regional Hospital, Orléans, France.
Department of Pharmacy, Rennes University Hospital, Rennes, France.
Department of Pharmacy, Hospices Civils de Lyon, Lyon, France.
Department of Pharmacy, Nîmes University Hospital, Nîmes, France.
Department of Pharmacy, Dijon University Hospital and LNC-UMR1231, Dijon, France.
Clinical Research Unit, Nantes University Hospital, Nantes, France.
EA3826 Laboratory, Nantes University; UFR des Sciences Pharmaceutiques, Nantes University, Nantes, France.
Department of Pharmacy, AP-HP Cochin Hospital, Paris, France.


This study aimed to assess patient investigational medication knowledge and to identify factors associated with medication understanding by adult outpatients included in clinical trials. A cross-sectional prospectively designed survey was conducted on consecutive volunteers at 21 university teaching hospitals (in France) from February to December 2014. Investigational medication understanding was assessed at the time of the first dispensing using a structured interviewer-administered questionnaire based on information obtained from the literature that provided an 8-point score. Demographic and other baseline data were collected using structured interviews. Of the 236 participants, 139 (58.9%) of the respondents were male, and the median age was 54.9 years (range: 18-83 years). The mean understanding score was 6.24 and 72.5% of the patients had a score of 6 or higher. In univariate analysis, the medication understanding score was negatively correlated with age (r = -0.15, p = 0.0247) and positively correlated with the level of education (r = 0.25, p = 0.0002). In multivariate analysis, prognostic factors of a higher medication understanding score were: graduation from high school or a higher level of education; HIV infection; phase II/III/IV studies; mention of the drug on the prescription form, and the dispensing of a single investigational medication. Only a quarter of the adult outpatients included in clinical trials had a maximum possible investigational medication understanding score. Being old and having a low level of education were found to be important risk factors for inadequate medication understanding. This and other data suggest that sponsors should encourage initiatives aimed at improving investigational medication understanding in adults enrolled in clinical trials.

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Conflict of interest statement

The authors have declared that no competing interests exist.

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