Reply to Goebel and Molloy

Making chronic pain count: empirical support for the ICD-11 classification of chronic pain

PURPOSE OF REVIEW

The purpose is to review the evidence that has been collected with regard to the new classification of chronic pain. In 2022, the World Health Assembly endorsed the 11 th revision of the International Classification of Diseases and Related Health Problems (ICD-11), and with it a new classification of chronic pain.

RECENT FINDINGS

The evidence from the formative field testing indicated that the categories were clearly delineated and the coverage of chronic pain excellent (<3% in remainder categories). Official WHO field tests showed that the classification works well within the technical parameters WHO classifications must conform to and outperformed the ICD-10 diagnoses in all respects. International field tests, in which clinicians diagnosed consecutive patients in settings of medium and high resources, showed substantial interrater reliability (κ = 0.596 to κ = 0.783) for the diagnoses and the clinicians rated their clinical utility as very high. Studies using complete hospital records demonstrated that with the information they contain, retrospective coding of the new diagnoses is possible and provides much more meaningful information than the ICD-10 diagnoses.

SUMMARY

The evidence supports the use of the new classification and highlights its informational gains - using it will contribute to making chronic pain count in many contexts.

Reliability and clinical utility of the chronic pain classification in the 11th Revision of the International Classification of Diseases from a global perspective: results from India, Cuba, and New Zealand

ABSTRACT

Chronic pain affects 1 in 5 persons and contributes substantially to the global burden of disease. The 11th Revision of the International Classification of Diseases (ICD-11) includes a comprehensive classification of chronic pain. The aim of this ecological implementation field study was to evaluate the classification's interrater reliability and clinical utility in countries with different income levels. The study was conducted in 4 pain clinics in Cuba, India, and New Zealand. Twenty-one clinicians used the ICD-11 to diagnose and code n = 353 patients with chronic pain. Of these, 111 were assessed by 2 clinicians, and Fleiss' kappa was calculated to establish interrater reliability for any diagnosis assigned to ≥15 patients. The clinicians rated the clinical utility of all diagnoses. The interrater reliability could be calculated for 11 diagnoses. It was substantial for 10 diagnoses and moderate for 1 (kappa: 0.596-0.783). The mean clinical utility of the ICD-11 chronic pain diagnoses was rated as 8.45 ± 1.69/10. Clinical utility was rated higher for ICD-11 than for the commonly used classification systems (P < 0.001, η2 = 0.25) and differed between all centers (P < 0.001, η2 = 0.60). The utility of the ICD-11 diagnoses was rated higher than the commonly used diagnoses in Dunedin and Havana, and no difference was found in Kolkata and Hyderabad. The study showed the high interrater reliability of the new chronic pain diagnoses. The perceived clinical utility of the diagnoses indicates their superiority or equality compared with the classification systems currently used in pain clinics. These results suggest the global applicability of the classification in specialized pain treatment settings.

Chronic pain in the 11th revision of the International Classification of Diseases: users' questions answered

ABSTRACT

The upcoming 11th revision of the International Classification of Diseases (ICD-11) will include a comprehensive classification of chronic pain for the first time, which is based on the biopsychosocial definition of chronic pain. This presents a great opportunity for pain research and clinical practice. The new classification consists of seven main diagnostic categories of chronic pain, which are further divided into increasingly specific levels of diagnoses. Each diagnosis is characterized by clearly defined operationalized criteria. Future users will need to familiarize themselves with the new system and its application. The aim of the present publication is to provide users of the ICD-11 chronic pain classification with answers to frequently asked questions regarding the ICD-11 as a whole, the ICD-11 chronic pain classification, and its application to common pain syndromes. The questions compiled here reached the International Association for the Study of Pain Task Force via different routes (e.g., at conferences, by letter, or during field testing). Furthermore, the authors collected questions posted to the ICD-11 browser and contacted early users of the classification to enquire about their most frequent difficulties when applying the new diagnoses. The authors of the present publication prepared answers to these frequently asked questions. This publication intends to act as a guide for the future users of the new ICD-11 chronic pain classification, hence facilitating its implementation.