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Updated: Jun 3, 2026

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
Published on: September 20, 2019
Improving recruitment in clinical trials: why eligible participants decline
Julie Brintnall-Karabelas1, Susanna Sung, Mary Ellen Cadman
1Human Subjects Protection Unit, Office of the Clinical Director, National Institute of Mental Health, 9000, Rockville Pike, Bethesda, MD 20892, USA. brintnaj@mail.nih.gov
Abstract:
There is a need to explore why protocol-eligible subjects refuse participation in clinical trials. Without a clear understanding, participation by representative populations will be an ongoing obstacle to recruitment. This descriptive research study analyzes frequency data regarding a sample of 965 individuals who, despite being eligible for studies with the National Institute of Mental Health intramural program, declined research participation. Overall, responses regarding reasons for declining fell into the following five categories: a result of specific protocol issues; inconvenience; for other reasons not mentioned; financial reasons; and, lastly, decided to participate elsewhere. The results of this study identify common factors which suggest there are steps that investigators can take to better accommodate the needs of the public and, consequently, improve research participation.
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