We searched the following 4 electronic databases up till March 6, 2023: MEDLINE (using Ovid), Embase, Cochrane, and Epistemonikos. The search strategy included both controlled vocabularies (eg, MeSH and Emtree) and keywords related to (1) the term “misinformation,” which included “infodemic,” “false news,” “disinformation” and (2) “systematic reviews.” We limited the search to reviews addressing misinformation and published within the past 5 years, starting from January 1, 2017. The final search strategies were developed with the help of an expert librarian after pilot testing with seed articles. The full search strategy for each database is provided in Multimedia Appendix 1.

In this study, we included review articles that stated misinformation or related terms as part of their objectives. A review was eligible if it conducted a systematic search of at least 1 database and reported on at least 1 definition for misinformation or related terms. Although the search was not restricted to English reviews, all of the eligible reviews were in English. We included qualitative and quantitative reviews. We excluded all abstracts, nonreviews, narrative reviews without any database search, studies not focusing on misinformation or related terms, studies unrelated to health, and reviews not providing any definition. Textbox 1 summarizes the eligibility criteria used in this scoping review.

Three reviewers (IKE, RH, and TH) worked in teams of 2, in duplicate and independently, to screen for potential eligibility of the titles and abstracts of the articles captured by the search. After obtaining the full texts of articles judged as potentially eligible, reviewers included eligible reviews. The principal investigator served as a third independent reviewer for resolving disagreements.

Teams of 2 review authors extracted the data from each included review in duplicate and independently. We used a standardized data abstraction form in Excel (Microsoft Corp). We met regularly to discuss progress and resolve any discrepancy through discussion. We abstracted definitions for misinformation and related terms (see Multimedia Appendix 2 [23-61]). We also abstracted the following information for each review: specific health topic, number of searched databases, and the misinformation themes addressed (see Table 1).

We used content data analysis to identify concepts within the identified definitions. After reading through the definitions several times to obtain a sense of all the definitions, we derived codes that captured key concepts [62]. We used deductive coding to map the definition concepts for each of the misinformation-related terms (see Table 2). Refinements to the language of the definition featured were done after discussions with all authors. When available, the source of the reported definition was noted, and the most used source was tracked (see Table 3).

Misinformation poses a challenge to decision-making. In the field of health, this can affect the clinical decision shared by the caregiver and patient and can affect health care policy making if any of the involved parties is misinformed. In this paper, we assess available definitions of misinformation and related terms used in health research systematic reviews. Across the reviews, there were concepts that were generally agreed upon. Misinformation includes false information that may or may not be intentional. Disinformation, on the other hand, includes intentional dissemination of false information. Fake news includes fabricated, false information disseminated in the format of official news. Infodemic is the information overload that happens in the setting of outbreaks or crises. Finally, malinformation includes accurate information that is used in the wrong context.

The definitions of misinformation and related terms in the literature on health are only 1 part of the extant literature. Fields such as political sciences and media have been well aware of this phenomenon and have studied it extensively. The effect of misinformation on the field of health has become clearer with the recent prominent public health crises including climate change and the COVID-19 pandemic. Our results showed that the definitions used in the field of health are consistent in key concepts but continue to show variability and inconsistency in others.

Definitions of misinformation and related terms vary in definition concepts. One of the clear variabilities in the health literature is related to the intentionality of misinformation. Seven definitions characterized misinformation as unintentional, while 5 definitions characterized it oppositely to be intentional. Another example is the definition of infodemic. Although almost all definitions mentioned the information overload concept, 6 definitions restricted it to false information while 9 definitions attributed it to a mix of valid and invalid information. A third example is the “based on expert opinion” definition concept. Only 2 definitions of misinformation included this concept and this is problematic since expert opinion can be considered a form of evidence. This observed variability and discrepancy highlights the importance of performing a formal consensus process in the field of health to reach a consensus around those definitions.

Definitions of misinformation and related terms contain concepts that require operationalization and clarity. Take for example the concepts of “false/inaccurate/incorrect” and the concept of “intentional.” The label of “false/inaccurate/incorrect” depends on how one defines accuracy and whether the certainty or quality of the evidence is considered. Evidence based on low certainty evidence (eg, a single observational case series) would differ from a higher level of certainty (eg, a systematic review of randomized controlled trials). As for intentionality, it is difficult to assess this as it relates to the intentions of the originator. To reliably assign intentionality to a published piece of false information, a researcher would need to investigate the original source and discern their intentions and purposes. This is not possible for much of the circulating misinformation, particularly those with unverifiable sources. These issues highlight that in addition to the need for a formal consensus process to agree on definitions, these definitions need to be clear and operationalized.

This scoping review has its own strengths and limitations. First, we followed a standard methodology for retrieving relevant articles using 4 distinct databases: Ovid MEDLINE, Embase, Cochrane, and Epistemonikos. Second, we used content data analysis to identify concepts of the retrieved definitions and map them across the misinformation-related terms. This scoping review, however, does not represent all definitions of misinformation in the extant literature, particularly from outside the health field. Also, limiting the search to the past 5 years may have resulted in missing relevant reviews published before that timeframe. However, since reviews published in the last 5 years should have included all the previously published original articles and since we are interested in looking at the current issues and definitions related to misinformation, we are not concerned about this limitation.

As for the implications of this work, our assessment of the definitions highlighted the presence of inconsistencies in the available definitions and some concepts that are difficult to operationalize. Health practitioners need to exert caution before labeling a piece of information as misinformation or any other related terms and only do so after ascertaining few characteristics of the piece of information at hand. A question one should ask is “How certain am I that this information is incorrect?” For disinformation, another question to ask is “How certain am I that this information is disseminated with the knowledge that it is incorrect?” Future work is needed to reach a consensus around clear and operational definitions of misinformation and related terms. This includes performing efforts to reach a formal consensus around those definitions and possibly undergoing qualitative exploratory efforts and interviews with stakeholders.

Misinformation poses a serious challenge to clinical and policy decision-making in the health field, both of which rely on accurate and reliable information. In this scoping review, we aimed to assess definitions of misinformation and related terms used in the health-related literature. We identified several definitions for misinformation and related terms that showed variability and included concepts that are not conducive to operationalization. Health practitioners need to exert caution before labeling a piece of information as misinformation or any other related term and only do so after ascertaining few characteristics of the piece of information at hand including the accurateness. Additional research is needed to reach a consensus around clear and operational definitions of misinformation and related terms, in order to more effectively study how misinformation affects health policies and research.