Summary of findings
Focus groups using the TDF  identified the complex interplay between chiropractors’ beliefs about implementing diagnostic-imaging guidelines for adult spinal disorders in private practice. Our findings were consistent with previous research exploring factors influencing general practitioners’ [33, 38, 43, 73–79] and chiropractors’ [5, 19, 47] use of guideline recommendations. Factors perceived to strongly influence lumbar x-ray–ordering practice clustered in five theoretical domains: beliefs about consequences (consequence of ordering x-rays and attitudes about the guidelines and professional experiences), social/professional role and identity (professional role, norms, boundary, autonomy, professional dignity or wanting to do the right thing, and agreement), social influences (influence from formal training, colleagues, publication), beliefs about capabilities (particularly when the patient’s diagnosis is unclear), and knowledge of the evidence base.
Having very few utterances coded in the skills domains in our study could be due to a number of reasons, including the low relevance of the domain as x-ray ordering differs from performing highly technical procedures, the nature of the questions themselves, coders’ interpretation of the domains and associated constructs, and coding within multiple domains. Only four utterances were elicited in the domain of emotion. Possible reasons for this low number of utterances include the following: (1) seeing back pain patients with a range of pain and disability levels may fail to elicit strong emotional reactions after several years in practice as one gains self-confidence ( beliefs about capabilities) and (2) focus groups may not be well suited to assess emotions among a group of healthcare professionals. Past reviews of barriers to guidelines and implementation have grouped attitudinal and emotional barriers together [33, 78]. In the current study, statements implying lack of self-efficacy, confidence, sense of authority, and accurate self-assessment were classified under the TDF domain of beliefs about capabilities.
Influence of professional identity
Heterogeneous and contradictory beliefs were expressed by participants about professional identity and cultural authority (social/professional role and identity). We observed disagreements among chiropractors about the scope of practice, professional autonomy, choice of lexicon (concept of chiropractic subluxation), and role of evidence. Professional identity remains an important source of tension between chiropractors [65, 80, 81], with paradigm differences (experiential vs evidence-based practice) likely driving other domains toward intention to manage back pain with or without x-rays. Such influence seems particularly important on the domains of beliefs about consequences (practice style, including x-ray–driven techniques), social influences (choice of literature and continuing education seminars), knowledge (guideline agreement), memory attention and decision making (taking x-rays if results are likely to change treatment protocols), and nature of the behaviors (ordering x-rays routinely or only in presence of red flags). A recent review of factors influencing health professionals’ intentions and behaviors found social/professional role and identity to be a substantial determinant of intention . The domain of social/professional role and identity may act as a mediator of x-ray ordering among chiropractors. This will be further considered in a predictive study.
The main differences observed between US and Canadian chiropractors included perceived threat of litigation and HMO incentives to conform with evidence-based practice, two factors known to influence adoption of guidelines in general [47, 73, 75, 83] and utilization of imaging studies in particular . Perceptions of organizational influences, reimbursement system, incentives for particular procedures, resources available to help implement CPGs, and logistics were elicited through the domains beliefs about consequences and, to a lesser extent, social influences and social/professional role and identity. For instance, maintaining a higher tier was deemed important as it provided increased practice latitude by reducing the volume of paper work needed to justify ordering of spine x-rays. Providers’ perceptions of the ASH tier administrative system fell under the domain of beliefs about consequences. Corresponding constructs (reinforcement/punishment/consequences, incentives/rewards, and sanctions/rewards) may be important to consider when designing a behavior-change intervention among chiropractors enlisted with networks of providers and HMOs.
While this study has provided valuable insight into the factors that may influence routine x-ray–ordering practices of chiropractors, there were several limitations. Recruitment was challenging, and two potential Canadian participants failed to show up. As a result, the number of participants in focus groups conducted was relatively small, and inclusion of other participants may have provided different beliefs either in favor of or against the targeted behavior . This is particularly relevant to our secondary objective aiming to compare responses from American (n = 14) and Canadian (n = 7) chiropractors. However, the age, gender, and years in practice were representative of North American chiropractors. Further, the diversity of views, attitudes, and beliefs and the wide range of self-reported behavior (from rarely using x-rays to routinely doing so) reported by practitioners in four distinct geographical locations suggest that this may not be a major problem .
It is likely that other important barriers to guideline implementation would have surfaced had we also interviewed patients. Interviews of back pain sufferers suggested that lumbar x-rays were very important . Patient’s views and expectations may considerably influence physician ordering and can be a barrier to appropriate use [38, 41, 43]. In the current study, chiropractors admitted ordering nonindicated x-rays to maintain trust, limit conflict, reduce patient anxiety, or protect professional dignity. Various strategies have been suggested to assist clinician and back pain patient encounter . Engagement of patients in the decision process is another avenue to explore .
One important challenge when coding focus groups into the theoretical domains was the lack of clear definitions and the overlaps between multiple domains (e.g.
beliefs about consequences and motivations and goals), rendering consensus difficult at times. In addition to using two independent coders with different professional backgrounds who reconciled differences at every step, findings were reviewed by a behavior psychologist (JJF) with in-depth knowledge of the TDF. Coding and subsequent agreement greatly improved after the first two transcripts. Validation of the TDF has resulted in a refined version addressing these shortcomings .
Although care was taken so participants would not get cues to answer in certain ways, agreement with other participants for fear of feeling marginalized by colleagues or to please the interviewer is a known weakness of focus groups. To account for social desirability, the interviewer asked participants to clarify nonverbal communication and coders considered patterns (e.g., changed or reversed statements after hearing from others, recurrent comments, and themes supported or rejected by more than one participant) when linking utterances with specific beliefs. Discussions after each focus group suggested the interview guide did not feel repetitive and questions relating to domains felt relevant to the participants. Furthermore, the frequency of responses throughout focus groups (Table 1) indicated that participants remained engaged despite the number of questions asked (43 with prompts) and associated length of focus group interviews (around 90 minutes).