The use of diagnostic coding in chiropractic practice

Diagnostic coding has several potential benefits, including improving the feasibility of data collection for research and clinical audits and providing a common language to improve interdisciplinary collaboration. The primary aim of this study was to determine the views and perspectives of chiropractors about diagnostic coding and explore the use of it in a chiropractic setting. A secondary aim was to compare the diagnostic coding undertaken by chiropractors and an independent coder.

A codin exercise based on the International Classification of Primary Care version 2, PLUS extension (ICPC-2 PLUS) provided the 14 chiropractors with some experience in diagnostic coding, followed by an interview on the topic. The interviews were analysed thematically. The participating chiropractors and an independent coder applied ICPC-2 PLUS terms to the diagnoses of 10 patients. Then the level of agreement between the chiropractors and the coder was determined and Cohen's Kappa was used to determine the agreement beyond that expected by chance.

From the interviews the three emerging themes were: 1) Advantages and disadvantages of using a clinical coding system in chiropractic practice, 2) ICPC-2 PLUS terminology issues for chiropractic practice and 3) Implementation of a coding system into chiropractic practice. The participating chiropractors did not uniformly support or condemn the idea of using diagnostic coding. However there was a strong agreement that the terminology in ICPC-2 PLUS would not be applicable or desirable for all practice types. In the coding exercise the chiropractors in total coded 202 diagnoses for 135 patients. The overall percentage agreement between the chiropractors and the coder was 52% (17% expected by chance) with a Kappa score of 0.4 (95% CI 0.3-0.7). Agreement was lower for more detailed coding (percentage agreement 35%; Kappa score of 0.3 (95% CI 0.2-0.5)).

It appears that implementation of diagnostic coding would be possible in the majority of the chiropractic practices that participated in this study. However for those chiropractors who do not focus on symptoms in their approach to clinical care, it could be challenging to use the ICPC-2 PLUS coding system, since ICPC-2 PLUS is a symptom-based classification.