Defining complementary, alternative and integrative medicine (CAIM) has been both complex and dynamic. The US National Centre for Complementary and Integrative Health (NCCIH) defines “complementary” medicine as a non-mainstream practice that is used together with conventional medicine and “alternative” medicine as a non-mainstream practice used in place of it. They defined “integrative health” as the bringing together of conventional and complementary approaches in a coordinated way [1]. In all three instances, these terms imply a relationship to conventional medicine, which may limit the categorization of therapies that have an undefined or non-existent relationship to conventional care [2]. Another challenge is that many of these terms are used interchangeably in the medical literature despite having marked differences in their meanings, and there is no universal consensus regarding which term ought to be used or is most “correct”. Other, less frequently used terms to describe these therapies also include “unconventional”, “unorthodox”, and “non-mainstream”, which are all reflective of therapies that are not typically taught at and/or provided by Western health care systems. Historically, subsets of such therapies have also been referred to as “quackery” and “charlatanism”, among other pejorative terms that are generally not used to describe them in the medical literature today [2].
Despite the difficulties in defining CAIM, it is well-documented that therapies described as complementary, alternative, traditional, or integrative are used with a high prevalence across the world. Many patients use CAIM in combination with, and a minority in lieu of, conventional care. Eighty-eight percent of World Health Organization member states (170 countries) have acknowledged the use of CAIM, having formally developed policies, laws, regulations, programs and offices for CAIM, as examples [3, 4]. The prevalence of CAIM use among many Western countries is highly variable, though in some countries it can be high; for example, among Canadians it is approximately 80% [5]. Across European countries, CAIM use has been found to vary from 0.3–86% [6, 7]. The use of CAIM is also known to be highly prevalent among patients living with a wide range of diseases/conditions; in cancer patients, as many as 90% report using some form of CAIM [8–10]. While one reason for these large differences in the prevalence of CAIM use across different jurisdictions may indeed be attributed to cultural norms or true preferences for or against CAIM, another reason includes the fact that there is simply no consensus, and therefore standard, for what is or is not included in an operational definition of CAIM. Even national surveys, themselves, do not contain an identical list of therapies when compared across time within countries.
The popularity and acceptance of different CAIM therapies have also not remained equal, but instead have varied over time, culture, and geographical region. For example, in the 1900s, animal magnetism (also known as mesmerism) was a type of CAIM that had gained some popularity in Europe and the United States, though conventional medical practitioners at the time viewed it with skepticism [11, 12]. Today, however, it is largely unpracticed and could arguably be excluded from an operational definition of CAIM. Other CAIMs have gained increased popularity, as well as greater acceptance from conventional healthcare practitioners in some regions of the world, such as chiropractic [13], naturopathy [14, 15], acupuncture [16, 17], and traditional Chinese medicine [18, 19]
Regardless of how CAIM therapies gain popularity among patients, the reasons that motivate patients to use CAIM are well-studied and some of the most common ones include: symptom relief, improved quality of life, augmentation of conventional therapy, support of one’s philosophical orientations towards health, and achievement in control over one’s care [20–22]. Due to the popularity of these therapies in some populations [23] and even some significant results of efficacy [24], they could arguably be offered in conventional healthcare settings including family physician practices, hospitals and hospices. The very fact that patients actively choose to use CAIM therapies, with many lacking safety and efficacy profiles, justifies the conducting of research in this field. New knowledge gained in turn, can be incorporated into the medical curriculum, and can help inform shared decision-making between healthcare practitioners and patients. Unsurprisingly, it is also known that the quantity of CAIM research being conducted has increased greatly over the past few decades [2, 25].
A theoretical definition of CAIM, however, is arguably not enough to inform certain types of CAIM research. Aside from studies testing specific CAIM therapies, such as those conducted through randomized controlled trials, currently published systematic reviews and bibliometric analyses on CAIM in general address multiple CAIM therapies and lack complete search strategies [26]. This can be attributed to the fact that no standard list of CAIM therapies is agreed upon within the research community, largely due to the lack of an existing comprehensive operational definition. This, in turn, results in a great omission of potentially eligible studies across these research methods, which yield biased or incomplete results. This justifies the development of an operational definition of CAIM, which if comprehensive, can serve as a solution. An operational definition serves a different purpose than a theoretical definition, as it identifies all (if not, as many as possible) therapies that can be categorized as CAIM, yet it is also a far more challenging definition to create. Like CAIM itself, an operational definition of it is dynamic, changing based on both historical time period in light of new evidence generated from medical research, and geographical location whereby many jurisdictions may integrate or consider their traditional system(s) of medicine as conventional care.
Developing an Operational Definition of CAIM
To date, only one operational definition of complementary and alternative medicine (CAM, not CAIM) has been published by Wieland et al. in 2011. They began by considering ways in which the 2005 Institute of Medicine theoretical definition of CAM, as therapies “other than those intrinsic to the politically dominant health system of a particular society or culture in a given historical period”, was relevant to the landscape of the early 21st century. To obtain a list of specific therapies, they examined sources in the US National Library of Medicine (NLM) PubMed database including the Medical Subject Heading (MeSH) definition of “Complementary Therapies” and the CAM on PubMed subset search strategy. They created an initial list of 70 alphabetical CAM terms or combinations of terms under subtopics according to the 5 categories of CAM therapies set by the National Center for Complementary and Alternative Medicine (NCCAM, the former name of the NCCIH at the time), and then subjected these terms to further qualifications and refinements based on setting, route of administration, and therapy/indication pairings [27]. Although the term “integrative” medicine had been in use as early as 1995 [28, 29], it remained a relatively infrequently used term at the time that Wieland et al.’s study was published [2]; thus, it is understandable why their definition did not include this term. Over the last decade, however, the use of the term “integrative” to refer to such therapies has become increasingly popular by both healthcare practitioners and researchers alike [2, 30, 31]. Considering that the NCCAM was renamed the National Centre for Complementary and Integrative Health (NCCIH) in December 2014, the update to their name is significant and indicates the emergence of patient, clinician, researcher and policy maker interest in an integrative approach in medical treatment plans [32]. It thus follows that a new operational definition that includes “integrative” is created.
Despite the omission of the term “integrative”, Wieland et al.’s study is a valuable starting point for the development of the present study’s operational definition, as they detailed how they constructed their definition, such as considering the historical context of a therapy, whether it is a standard treatment within the dominant medical system, whether it is a standard treatment for a given condition, and the setting in which the therapy is provided [27]. A number of sentiments shared by Wieland et al., with respect to the value of an operational definition, therefore, equally apply to the present study. An operational definition of CAIM would support the harmonization of research, as CAIM-specific research databases can be developed in a more standardized fashion with respect to classifying what constitutes included therapies. This may also allow for more effective collaboration among research groups, as a general consensus can be reached rapidly [27]. Operationalization also enables the precise comparison of different CAIM areas over time and across investigators [27]. Undoubtedly, value has emerged from Wieland et al.’s (2011) work, as a variety of studies have utilized their operational definition to inform their research. Some examples include a literature review of traditional and complementary medicine in the context of mental health services in low- or middle-income countries [33] and a systematic review of the cost-effectiveness of common complementary and integrative therapies [34]. Studies have also used Wieland et al.’s operational definition with some modification [6], or in combination with other approaches to propose an operational definition for clinical pathways [35].
The methods used by Wieland et al. (2011) to construct their operational definition, was not without its weaknesses, however, and the present study aims to update and build on their work in a few ways. Wieland et al. (2011) only reviewed two sources within the US National Library of Medicine’s PubMed database, the MeSH definition of ‘Complementary Therapies’ and the Complementary Medicine subset search strategy, to generate a listing of specific therapies [27]. In light of these shortcomings, the objective of the present study is to create an operational definition of CAIM derived from a systematic search, and to construct search strategies for common academic databases based on our findings to improve and standardize search strategies pertinent to future CAIM research.