Scientific literature applicable to chiropractic practice proliferates in quantity, quality, and source. Chiropractic is a worldwide profession and varies in scope between states or provinces and from country to country. It is logical to consider that the focus and emphasis of chiropractic education varies between programs as well. This original research study endeavored to determine “essential literature” recommended by chiropractic faculty. The purpose of this article is (1) to share our results and (2) to promote discussion and explore means for future collaboration of chiropractic faculty through a worldwide platform.
A 2-phase recruitment occurred initially at the institutional level and subsequently at the faculty level. A Web-based survey used qualitative data collection methods to gather bibliographic citations. Descriptive statistics were calculated for demographics, and citation responses were ranked per number of recommendations, grouped into categories, and tabulated per journal source and publication date.
Forty-one chiropractic programs were contacted, resulting in 30 participating chiropractic programs (16 US and 14 international). Forty-five faculty members completed the entire survey, submitting 126 peer-reviewed publications and 25 additional citations. Readings emphasized clinical management of spine pain, the science of spinal manipulation, effectiveness of manual therapies, teaching of chiropractic techniques, outcomes assessments, and professional issues.
A systematic approach to surveying educators in international chiropractic institutions was accomplished. The results of the survey provide a list of essential literature for the chiropractic profession. We recommend establishing a chiropractic faculty registry for improved communication and collaboration.
The proliferation of the scientific literature poses a challenge to the clinician and educator who desires to be conversant in the research status of a profession. Our study aimed to develop a mechanism to identify and disseminate literature “essential” to the chiropractic profession.1 Available research continues to grow at an astounding pace.2 Literature affecting the practice of chiropractic is found in a wider variety of resources as research continues to evolve, as recently demonstrated in the American College of Physicians recent clinical guideline for acute, subacute, and chronic low back pain.3 The quality of research available also continues to improve through the editorial use of transparency instruments available through the EQUATOR Network, such as CONSORT, STROBE, PRISMA, CARE, STARD, and AGREE,4 and quality database resources, such as Cochrane Collaboration5 and ClinicalTrials.gov.6
Chiropractic is a worldwide profession. In the United States, many chiropractic programs are private educational institutions and focused predominantly if not solely on the education of chiropractors and chiropractic staff. Internationally, chiropractic programs may exist independently or as part of a larger university system. Chiropractic practice varies in scope between states or provinces and from country to country. It is logical to consider that the focus and emphasis of chiropractic education, philosophy, and research varies between programs as well.
Our current students are the future leaders of our profession; we strive to know how they are molded. What we do not know, however, is whether how or when quality literature disperses through our educational system. Consequently, we wondered, what literature do chiropractic faculty deem “essential” for every chiropractor of which to be aware? The purpose of this study was to survey chiropractic faculty worldwide to determine what literature these faculty deem essential reading for chiropractors and chiropractic students. We share these results not only as a reference of teaching faculty “essential literature” but also to promote discussion and find ways for future collaboration of chiropractic faculty through a worldwide platform.
We conducted an online, descriptive survey to understand what chiropractic program faculty consider to be essential reading for the chiropractic profession. The human protections administrator for Palmer College of Chiropractic determined that this study was exempt per 45 CFR 46, IRB Assurance # X2014-10-17-M. The survey was conducted from March through May 2015.
Participant recruitment occurred on 2 levels: chiropractic educational institutions and individual faculty members (Fig. 1). We first obtained a list of international and US (n = 41) chiropractic programs and their contact information from the World Federation of Chiropractic (WFC) (http://www.wfc.org). The detailed list included accreditation agency, country, school, department (if applicable), physical address, phone, fax, and general e-mail address, as well as a contact name with their professional designation, job title, and phone number, fax, and e-mail address. We e-mailed the designated representative from each chiropractic program requesting a procedure to acquire e-mail addresses for all faculty members in their program; 21 programs replied to this e-mail request. Personalized follow-up by phone call was necessary to determine appropriate channels for other institutions (n = 4). Several lists (n = 5) were obtained via hand retrieval of faculty listings from a program website. Human resources departments were also used as a source for obtaining e-mail contact information. In total, 30 of 41 chiropractic institutions participated in this study, with 11 chiropractic educational institutions (1 US, 10 international) not responding to requests for information. In addition to direct and indirect recruitment of chiropractic faculty, we also introduced the survey to prospective respondents via verbal announcements and handouts at the 2015 Association of Chiropractic Colleges Research Agenda Conference.
Survey Development and Implementation
We developed a Web-based survey in ASP.NET v4.0 in C# and Structured Query Language (SQL) using Microsoft Visual Studio 2010 (Microsoft Corporation, Redmond, WA). All data were stored on an internal Microsoft SQL Server 2014. The survey was pretested among chiropractic faculty at our home institution for clarity, ease of use, and content validity.
The survey was launched in March 2015. Recipients received a survey link, pass code, and cover letter with a short explanation regarding the purpose and methods of the study via e-mail. Recipients received an e-mail and link either directly from our Web page/server (direct recipients) or from an individual designated from the program responsible for survey dissemination (indirect recipients). Direct recipients received up to 4 automated reminder messages, depending on their response status within the software. Institutional contacts for indirect recipients received up to 3 prompts to disseminate reminders to faculty.
The survey used qualitative data collection methods. Respondents listed the author, title, journal, and year of an article the respondent considered essential reading for chiropractors and chiropractic students and included a short statement indicating why the recommended article was important. Demographic data collected included respondents' age, gender, hours per week reading professional literature, years of teaching experience, chiropractic program affiliation, primary assignment (administration, classroom, clinical, research, or other), full-time or part-time status, whether a chiropractor or not (if yes, chiropractic program of training), highest degree achieved, and clinical practice status.
Descriptive statistics were calculated for demographics using SAS v9.4 (SAS Institute Inc, Cary, NC). Citations were ranked per number of recommendations, with the submission results divided into 2 categories: peer-reviewed and non–peer-reviewed publications. Further, submissions were tabulated per journal source and publication date.
We established a method of distribution with 16 of the 17 US chiropractic programs: 5 responded to the initial e-mail contact, 1 responded to a follow-up e-mail contact, 4 responded after contacting an individual known personally by 1 of the authors, 5 program faculty lists were obtained via hand retrieval from a program website, and 1 list was retrieved by contacting the program's human resources department. Of the US programs, 6 programs did not share faculty e-mail lists but agreed to distribute the survey via an e-mail to faculty members on our behalf. Five programs shared complete faculty e-mail lists. We manually retrieved e-mail lists from the websites of 5 additional US programs due to an absence of response after multiple attempts and approaches. One program was unresponsive to multiple e-mail requests to direct individuals, general Web inquiry, and voice mails left at human resources.
We established a method of distribution with 14 of 24 programs outside the United States: 9 responded to the initial email inquiry, 2 responded to follow-up inquiries, and 2 responded to inquiries submitted via Web inquiry or program website. Of those, 5 chiropractic program faculty received direct e-mails, while 9 programs agreed to forward the survey invitation to their faculty. The 11 chiropractic programs that did not participate were unresponsive to at least 2 e-mail requests to direct individuals as well as general Web inquiry. E-mails were primarily sent in English but also included duplicate text converted via Google Translate when appropriate. The authors chose not to attempt to communicate with human resource departments via phone in some cases due to time zone differences and potential language barriers.
The survey was e-mailed directly to 713 chiropractic program faculty members (108 international in 5 programs and 605 US in 10 programs) and indirectly to 14 programs worldwide (6 US and 9 international). Figure 2 shows a map of chiropractic program distribution worldwide.
While 173 respondents completed the welcome screen and 24 declined participation, only 45 respondents completed the entire survey through the demographic information section; 47 respondents submitted articles. The response rate is not possible to compute due to the unknown distribution number, but we estimate that it is below 5%. The mean age of respondents was 50.2 (SD = 9.8) years, with the majority female (n = 30) and chiropractors (n = 34). Slightly over half were full-time (n = 24), with the average time teaching in a chiropractic program at 12.97 (SD = 10.6) years. Thirty reported formal training in an evidence-based practice within the past 5 years and spent an average of 7.2 (SD = 3.36) hours per week reading professional literature. Most respondents were involved in classroom instruction of clinical sciences (n = 16) or research (n = 13), with most nonengaged in clinical practice (n = 28). Table 1 presents the remaining demographic information for the sample.
Respondents submitted a mean (SD, range) of 4.5 (2.5, 1–10) articles. One hundred and twenty-six peer-reviewed publications were submitted as essential literature for the chiropractic profession. Twenty-five submissions were non–peer reviewed in nature, 19 of which were published textbooks. Recommended articles were published in the Journal of Manipulative and Physiological Therapeutics (n = 30), Spine (n = 14), The Spine Journal (n = 9), Chiropractic and Manual Therapy (n = 8), Journal of the Canadian Chiropractic Association (n = 7), and a variety of other chiropractic, manual/physical therapy, and internal medicine journals. Publication years ranged from 1979 to 2015; most publication dates fell in the 2006–2010 (n = 38) and 2011–2015 (n = 63) ranges.
Table 2 reports the 126 peer-reviewed submissions. Citations are listed first by the number of recommendations by survey respondents and then alphabetically by title and author/citation. A quotation from the recommending respondents is provided demonstrating the importance of the article. Articles highlighted in gray are available currently on the WFC Suggested Reading List for Chiropractic (accessed May 18, 2017).
Table 3 reports the 25 non–peer-reviewed submissions, listed first by number of recommendations and then alphabetically by title and author/publisher or source, also with a quotation from the recommending respondent.
Literature With Multiple Recommendations
Eighteen peer-reviewed articles and 1 textbook received multiple recommendations. An article by Cassidy and colleagues, “Risk of vertebrobasilar stroke and chiropractic care: results of a population-based case control and case-crossover study,” received 11 submissions as essential literature for chiropractors.7 Second in ranking was Bronfort et al,8 “Effectiveness of manual therapies: the UK evidence report.” Five articles received 3 recommendations: “A theoretical model for the development of a diagnosis-based clinical decision rule for the management of patients with spinal pain” (Murphy9), “Clinical effectiveness of manual therapy for the management of musculoskeletal and non-musculoskeletal conditions: a systematic review and update of the UK evidence report” (Clar et al10), “Diagnosis and treatment of low back pain: a joint clinical practice guideline from the American College of Physicians and the American Pain Society” (Chou et al3), “Dose-response and efficacy of spinal manipulation for care of chronic low back pain: a randomized controlled trial” (Haas et al11), and “Review of methods used by chiropractors to determine the site for applying manipulation” (Triano et al12).
Peer-Reviewed Literature With Single Recommendations
The predominance of submissions primarily referenced clinically applicable topics, including treatment of neck/back pain/headaches, diagnostic accuracy, specific case studies, and treatment of certain populations.21,25–73 Many articles considered essential addressed basic science issues, such as mechanisms, biomechanics, chemical effects, and other investigations.29,74–99 There were several educationally themed submissions regarding ethics, consensus terminology, attitudes, and learning techniques.100–109 Another theme was a significant amount of clinical decision-making or guideline-based treatment topics.70,110–118 Several submissions regarded profession-wide issues, including future direction and the subluxation debate, and others regarded current state of research and profession-wide policies.119–127
Non–Peer-Reviewed Literature With Single Recommendations
Nine textbooks were recommended encompassing clinical examination,128,129 decision making/management,130–132 or technique/treatment133–136 of and by chiropractors. Six textbooks were recommended, including evidence-based clinical practice,137 neurobiologic mechanisms,138 biomedical ethics,139 biochemistry,140 a single-volume anatomy atlas,141 and 2 regarding immunology.142,143 Five submissions in this category were summaries or overviews.144,145 Three submissions were compilations available through governmental process or distribution.146–148
Comparison of Essential Literature Findings to WFC Suggested Reading List
Articles highlighted in Table 2 identify readings common to the Essential Literature for Chiropractic: International Faculty survey and the WFC Suggested Reading List. Forty-five (36%) of the readings were shared by both lists. Among the Essential Literature readings not included in the WFC offerings, many recommendations were for articles that would guide the thinking of novice chiropractic practitioners. For example, chiropractic faculty recommended 13 papers on key clinical trials or observational studies on chiropractic, spinal manipulation, or manual therapy techniques.25,29,32,34,44,60,62,64,65,72 These teachers cited numerous articles (n = 9) on clinical decision making, such as classification systems, algorithms, or clinical prediction rules.9,19,42,51,70,102,110,111,149 Recent systematic reviews, clinical guidelines, and best practices related to conservative care of musculoskeletal conditions also garnered many endorsements (n = 9).37,39,47,109,114,115,118,150,151 Faculty also suggested articles on clinical assessment or training methods (n = 7), case studies (n = 4), outcomes assessment (n = 3), and adverse events (n = 3). Other common topics included those on models or mechanisms of pathology or interventions (n = 14) as well as professional issues or debates (n = 11).
Qualitative Comments to the Survey
Some respondents included qualitative comments in their responses to the survey. Several who declined participation stated they were not chiropractors or that they taught nonchiropractic courses, such as business. This response contrasted with the survey invitation, which was open to all chiropractic program faculty regardless of their training as chiropractors or the types of classes they taught. Others declined, as they considered themselves administrators or researchers rather than faculty members. Several other declines noted that they were not up to date with chiropractic professional literature, stating, “I can't think of 3” or “not something I do regularly.” Other nonrespondents noted that they had declined participation but received another request or were concerned that there was not information about how the survey would be used and that “what is essential today might be outdated next year.” Finally, 1 respondent suggested that the time and effort of this survey was redundant to a program under development through the WFC for a suggested reading list for chiropractic.
This survey of international chiropractic program faculty was a follow-up evaluation from a survey of chiropractic research leaders on the essential literature for the chiropractic profession. We made a concerted effort to reach faculty members in all chiropractic educational programs (n = 41) listed on the WFC Web page; however, only 47 respondents from 16 chiropractic programs submitted citations. While the estimated response rate (<5%) was disappointing, and much lower than is typical of surveys of chiropractors,152 those who participated provided thoughtful responses, resulting in a lengthier list than our previous survey.1 The greater response rate from female faculty is unexpected. We suspect that chiropractic faculty worldwide is not represented by more females than males—particularly a 3:1 ratio—although these statistics are not readily known. An online study of faculty in 2008 showed a response rate of females 12% higher than males.153 Although we cannot speculate regarding the percentage of respondents, this is an interesting correlation. Note also that respondents are primarily from “classroom: clinical sciences” and “research.”
The results of the survey provide a useful resource for clinicians, educators, and students and provide a list for essential reading, and should be considered a complement to the WFC Suggested Reading List for Chiropractic, an online resource inspired by our initial survey of Essential Literature for the Chiropractic Profession and first published as this current survey was in its implementation stage. Essential readings with numerous recommendations from multiple participants included the management of low back pain and neck pain, basic science and biomechanical investigations of spinal manipulation, the effectiveness of manual therapy interventions, teaching and application of chiropractic techniques, outcomes assessment, and professional issues for chiropractic. Interestingly, our comparison of the Essential Literature and the WFC Suggested Reading List found important gaps in topics of interest to chiropractic faculty. Indeed, 64% of Essential Literature articles were not included on the Reading List, such as those on chiropractic education or clinical prediction rules. Chiropractic faculty in this survey also recommended many recent articles not added to WFC Suggested Reading List (although some may have been disseminated through the “This Week's Papers” function of the website). Reading List curators may bear our findings in mind when updating articles to ensure that the offerings are useful not only for readers well versed in the chiropractic literature who might be seeking new information but also for students, novice clinicians, and chiropractic faculty who require access to foundational works.
Most of the recommended peer-reviewed literature included studies high in strength of research or generalizability/applicability (systematic reviews, clinical trials, consensus panels, and so on). A few lower-level-evidence pieces (e.g., case studies and case series) were recommended. Conflict may arise regarding whether lower-level evidence may be considered “essential.” While the rationale for choosing case studies over other, higher levels of evidence is not known, some respondents may consider case reports “essential” due to the uniqueness of the case or for the lessons they offer chiropractic students who are learning to recognize common clinical presentations and diagnose complex health conditions. Chiropractic faculty members are encouraged to frame case studies within the context of the level of evidence they provide and to train students to seek information from systematic reviews and randomized clinical trials whenever these are available.137
The challenges we encountered while implementing this survey may be of similar concern for researchers attempting to conduct studies with chiropractic faculty both in the United States and internationally. We discovered that there is no established, reliable, and current mechanism for communicating with faculty members across chiropractic programs. The WFC was efficient and responsive in sharing contact information. However, we had difficulty reaching several institutions either because the contact was not current or because the school officials did not respond to our requests for information. When chiropractic institutions did not reply to our requests, we attempted to gather faculty contact information directly from the educational institution's website. However, the chiropractor faculty and departments at some educational institutions were not identifiable on the designated website. While this may be understandable in some instances, we found some nonresponse (to phone calls or e-mails) somewhat unexpected from an academic institution. Of more concern is that prospective and current chiropractic students may not have access to up-to-date background or contact information about their faculty members, nor is the composition of the faculty at some chiropractic institutions transparent to those outside their organizations.
While we spent considerable time and thought developing and testing our Web mechanism for data entry and ease of use, we strive to clarify the extensive work that was necessary to compile the list of faculty. The WFC was efficient in responding to our list of international chiropractic programs, which included contact information and multiple names. The Association for Chiropractic Colleges (ACC) is another resource for information and collaboration. Membership in both organizations (1 by individual and 1 by institution) does come with a fee. Involvement is either on an administrative level or by incurring substantial cost in attending conferences. Further, membership in such chiropractic associations may be closed to faculty members who are nonchiropractors, as were 20% of our survey respondents. We are aware of only 1 other resource for connecting faculty through a listserv of members through the American Chiropractic Association (ACA), although the European Chiropractors' Union (ECU) also appears to have that capacity.154 To our knowledge, the ACA list is not widely used, and we were unable to ascertain if the ECU maintains a faculty listserv by a review of their website.
In our information age, should we be able to easily form a chiropractic faculty association? Should this be a subset of the WFC? Whether through the rigors of existing organizational structure or through a more informal social media prospect, this seems a viable and beneficial option. While we are no longer interested in pursuing a compilation of essential literature, a grassroots platform (as well as a vetting mechanism for its use) would surely provide for a low-cost, feasible mechanism for establishing communication, fostering collaborations, and conducting research with chiropractic faculty worldwide.
The response rate to this survey was poor. While the acquisition of faculty contact information was favorable for some chiropractic programs, it was very challenging to obtain cooperation and/or responses from many others. While we could contact most of the US chiropractic programs, many international chiropractic programs did not reply to our requests for information. Therefore, we are not able to make a comparison of readings lists provided by faculty from different geographic regions, as any conclusions we might make based on such an underrepresentative analysis would be spurious at best.
A systematic approach to surveying educators in all international chiropractic institutions was accomplished. The results of this survey provide a cursory list of essential literature for the chiropractic profession. An interesting follow-up or related study would be an examination of the scientific literature used in chiropractic program syllabi. We recommend establishment of a chiropractic faculty registry for ease of communication and collaboration. This could be done under a current established organization, such as the WFC, or alternatively as an international entity affiliated with the ACC.
The authors wish to acknowledge the Palmer College of Chiropractic and the Palmer Center for Chiropractic Research for supporting the human and technical resources allocated to this project.
FUNDING AND CONFLICTS OF INTEREST
No conflicts of interest and no disclaimers to declare. Although Palmer College of Chiropractic supported this research efforts indirectly, no specific funding was received or requested to support this study.
Barbara Mansholt is an associate professor in the clinic at Palmer College of Chiropractic (1000 Brady Street, Davenport, IA 52803; firstname.lastname@example.org). Stacie Salsbury is an assistant professor at the Palmer Center for Chiropractic Research, Palmer College of Chiropractic (741 Brady Street, Davenport, IA 52803; email@example.com). Lance Corber is the data core manager in the office of data management and biostatistics at Palmer Center for Chiropractic Research, Palmer College of Chiropractic (741 Brady Street, Davenport, IA 52803; firstname.lastname@example.org). John Stites is a professor and director of community clinics with Palmer College of Chiropractic (2001 52nd Avenue, Moline, IL 61265; email@example.com). Address correspondence to Barbara Mansholt, 1000 Brady Street, Davenport, IA 52803; firstname.lastname@example.org. This article was received March 7, 2017, revised May 24, 2017, and accepted June 18, 2017.
Concept development: BM, SS, JS. Design: BM, SS, JS, LC. Supervision: BM. Data collection/processing: BM, LC. Analysis/interpretation: LC, SS. Literature search: BM, SS, JS. Writing: BM, SS, LC. Critical review: BM, SS.