Variation in use of radiographs in chiropractic care: a cross-sectional study.

Background: There appears to be a substantial variation in the use of radiographs in chiropractic clinics, but the reasons for this variation are not well understood. This study examined the use of radiography over a one-year period in Danish chiropractic clinics and explored its associations with clinic- and chiropractor-level characteristics.

Methods: Data on the number of unique patients consulting a chiropractor and those receiving radiography between 1 January 2022 and 31 December 2022 were obtained from a Danish national registry. Information on clinics including the number of chiropractors, geographical region, multidisciplinary status, and types of other healthcare professionals employed, as well as chiropractor characteristics (age, gender, seniority, and country of education) was collected from clinic websites and a national register of Danish healthcare professionals. The proportion of patients undergoing radiography was calculated for each clinic. Associations with clinic and chiropractic characteristics were tested using chi-square or t-tests, as appropriate. Characteristics were also compared between clinics with and without in-house radiographic imaging facilities.

Results: A total of 237 chiropractic clinics and 657 chiropractors were included. The mean age of chiropractors was 47 years (SD 12.8), 53% were women and 61.8% were educated in Denmark. Clinics with radiographic facilities (n = 161, 68%) tended to be larger and more likely to be multidisciplinary than clinics without (n = 76, 32%). Among clinics with radiographic facilities, the proportion of patients receiving radiography was 9.5% (95% CI 8.4-10.6%), ranging from 0 to 39%. No associations were found between radiography use in clinics with in-house radiographic facilities and clinic or chiropractic characteristics. In clinics without radiographic facilities, only 1.1% of patients were referred for radiography via chiropractic service codes, although this is likely an underestimation, as referrals to public hospitals were not captured.

Conclusion: Although considerable variation in radiography use was observed across Danish chiropractic clinics with radiographic facilities, this was not explained by measured clinic or chiropractic characteristics. The true extent of radiography use in clinics without in-house facilities remains uncertain. Further research into clinical decision-making is needed to support evidence-based, transparent and consistent practice, potentially using qualitative methods to better understand the reasons behind the observed variation.