RT Journal Article
SR Electronic
T1 Global insight into rare disease and orphan drug definitions: a systematic literature review
JF BMJ Open
JO BMJ Open
FD British Medical Journal Publishing Group
SP e086527
DO 10.1136/bmjopen-2024-086527
VO 15
IS 1
A1 Abozaid, Ghada Mohammed
A1 Kerr, Katie
A1 Alomary, Hiba
A1 Al-Omar, Hussain A
A1 McKnight, Amy
YR 2025
UL http://bmjopen.bmj.com/content/15/1/e086527.abstract
AB Objectives This study sheds light on the available global definitions, classifications, and criteria used for rare diseases (RDs), ultrarare diseases (URDs), orphan drugs (ODs) and ultraorphan drugs (UODs) and provides insights into the rationale behind these definitions.Design A systematic literature review was conducted to identify existing definitions and the criteria used to define RDs, ODs and their subtypes.Data sources Searches were performed in the PubMed/Medline, Embase, Scopus and Web of Science (Science and Social Sciences Citation Index) databases covering articles published from 1985 to 2021.Eligibility criteria for selecting studies English-language studies on the general human population were included if they provided definitions or criteria for RDs, ODs and/or their subtypes without restrictions on publication year, country or jurisdiction.Data extraction and synthesis Two independent reviewers conducted the search, screening and data extraction. Narrative synthesis, content analysis and descriptive analyses were conducted to extract and categorise definitions and criteria from these sources. Study quality was assessed using the Joanna Briggs Institute (JBI) critical appraisal tools.Results Online searches identified 2712 published articles. Only 93 articles met the inclusion criteria, with 209 distinct definitions extracted. Specifically, 93 of these articles pertained to 119 RDs, 11 URDs, 67 ODs and 12 UODs. These definitions varied in their reliance on prevalence based and other contextual criteria.Conclusion Prevalence-based criteria alone pose challenges, as disease frequencies differ by country. Establishing country-specific definitions can enhance understanding, support intercountry evaluations, improve healthcare efficiency and access to ODs, and strengthen equity and equality in healthcare. Such efforts would also promote research and development and support better outcomes for patients with complex and rare conditions.PROSPERO registration number CRD42021252701.All data relevant to the study are included in the article or uploaded as supplementary information. All of the study's data were fully accessible to the author(s), who also bear responsibility for the data's accuracy and integrity. This study has no more unpublished data. There are no more statistics available.