Clinicians diagnosing virtual patients with the classification algorithm for chronic pain in the ICD-11 (CAL-CP) achieve better diagnoses and prefer the algorithm to standard tools: An experimental validation study

Background: The ICD-11 classification of chronic pain comprises seven categories, each further subdivided. In total, it contains over 100 diagnoses each based on 5-7 criteria. To increase diagnostic reliability, the Classification Algorithm for Chronic Pain in the ICD-11 (CAL-CP) was developed. The current study aimed to evaluate the CAL-CP regarding the correctness of assigned diagnoses, utility and ease of use.

Methods: In an international online study, n = 195 clinicians each diagnosed 4 out of 8 fictitious patients. The clinicians interacted via chat with the virtual patients to collect information and view medical histories and examination findings. The patient cases differed in complexity: simple patients had one chronic pain diagnosis; complex cases had two. In a 2 × 2 repeated-measures design with the factors tool (algorithm/standard browser) and diagnostic complexity (simple/complex), clinicians used either the algorithm or the ICD-11 browser for their diagnoses. After each case, clinicians indicated the pain diagnoses and rated the diagnostic process. The correctness of the assigned diagnoses and the ratings of the algorithm's utility and ease of use were analysed.

Results: The use of the algorithm resulted in more correct diagnoses. This was true for chronic primary and secondary pain diagnoses. The clinicians preferred the algorithm over the ICD-11 browser, rating it easier to work with and more useful. Especially novice users benefited from the algorithm.

Conclusions: The use of the algorithm increases the correctness of the diagnoses for chronic pain and is well accepted by clinicians. The CAL-CP's use should be considered in routine care and research contexts.

Significance statement: The ICD-11 has come into effect in January 2022. Clinicians and researchers will soon begin using the new classification of chronic pain. To facilitate clinicians training and diagnostic accuracy, a classification algorithm was developed. The paper investigates whether clinicians using the algorithm-as opposed to the generic tools provided by the WHO-reach more correct diagnoses when they diagnose standardized patients and how they rate the comparative utility of the diagnostic instruments available.