Identifying Factors Likely to Influence the Use of Diagnostic Imaging Guidelines for Adult Spine Disorders Among North American Chiropractors

The high prevalence of back and neck pain results in enormous social, psychological, and economic burden. Most seeking help for back or neck pain consult general practitioners or chiropractors. Chiropractic is a regulated health profession (serving approximately 10 – 15% of the population) that has contributed to the health and well-being of North Americans for over a century. Despite available evidence for optimal management of back and neck pain, poor adherences to guidelines and wide variations in services have been noted. For instance, overuse and misuse of imaging services have been reported in the chiropractic literature. Inappropriate use of spine imaging has a number of potential adverse outcomes, including inefficient and potentially inappropriate invasive diagnosis and subsequent treatment, and unnecessary patient exposure to ionizing radiation. Although evidence-based diagnostic imaging guidelines for spinal disorders are available, chiropractors are divided on whether these guidelines apply to them. While guidelines can encourage practitioners to conform to best practices and lead to improvements in care, reviews have demonstrated that dissemination of guidelines alone is rarely sufficient to optimise care. Evidence regarding effective methods to promote the uptake of guidelines is still lacking. There is growing acceptance that problem analysis and development of interventions to change practice should be guided by relevant theories and tailored to the target audience. To date, very little knowledge translation research has addressed research-practice gaps in chiropractic. This thesis reports rigorous methods to: (1) assess practice and providers’ characteristics, (2) determine baseline rates and variations in spine x-ray ordering, (3) evaluate the impact of disseminating guidelines to optimise spine x-ray ordering, and (4) assess determinants of spine x-ray ordering and potential targets for change prior to the design of a tailored intervention. A mixed method using two disciplinary perspectives (epidemiology and psychology) was undertaken. A cross-sectional analysis of administrative claims data was carried out on a sample of chiropractors enlisted in a large American provider network. Despite available clinical practice guidelines, wide geographical variations in x-ray use persist. Higher x-ray ordering rates were associated with practice location (Midwest and South US census regions), setting (urban, suburban), chiropractic school attended, male provider, employment, and years in practice. The impact of web-based guideline dissemination was evaluated over a five year period using interrupted time series and demonstrated a stepwise relative reduction of 5.3% in the use of x-rays. Passive guidelines dissemination appeared to be a simple, cost effective strategy in this setting to improve but not optimise x-ray ordering rates. Focus groups using the theoretical domains framework were conducted among Canadian and US chiropractors to explore their beliefs about managing back pain without x-rays. Findings were used to develop a theory-based survey to identify theoretical constructs predicting spine x-ray ordering practice. Psychological theories and theoretical constructs explained a significant portion of the variance in both behavioural simulation and intention. Results from this thesis provide an empirically-supported, theoretical basis to design quality improvement strategies to increase guidelines adherence and promote behaviour change in chiropractic. Other researchers interested in improving uptake of evidenced-based information could use this method in their own setting to investigate determinants of behaviour among other professional groups. Future research may use knowledge gained to inform the development and evaluation of a theory-based tailored intervention to improve guideline adherence and reduce the use of spine x-rays among targeted providers