A Scoping Review of Chronic Low Back Pain Classification Schemes Based on Patient-Reported Outcomes

Background: In 2014, the National Institutes of Health Pain Consortium Research Task Force recommended that patients with chronic low back pain (CLBP) be stratified by its impact on their lives. They proposed the Impact Stratification Score (ISS) to help guide therapy and facilitate study comparability. The ISS has been evaluated as a continuous measure, but not for use as a stratification or classification scheme.

Objectives: Identify the characteristics of successful schemes to inform the use of the ISS for stratification or classification.

Study design: Scoping review of the peer-reviewed literature.

Methods: Search of PubMed, CINAHL, and APA PsycInfo to identify patient self-report-based classification schemes applicable to CLBP. Data were captured on the methods used for each scheme's development, the domains covered, their scoring criteria and what the classification has successfully measured. The study was reviewed and approved by the RAND Human Subjects Protection Committee (2019-0651-AM02).

Results: The search identified 87 published articles about the development and testing of 5 classification schemes: 1) The Subgroups for Targeted Treatment (STarT) Back Screening Tool, 2) Multiaxial Assessment of Pain, 3) Graded Chronic Pain Scale, 4) Back Pain Classification Scale, and 5) Chronic Pain Risk Score. All have been shown to be predictive of future outcomes and the STarT Back has been found useful in identifying effective classification-specific treatment. Each scheme had a different classification scoring structure, was developed using different methods, and 3 included domains not found in the ISS.

Limitations: Expanding the search to other databases may have identified more classification schemes. Our minimum number of publications inclusion criterion eliminated dozens of cluster analyses, some of which may have eventually been replicated.

Conclusions: The methods used to develop these successful classification schemes, especially those that use straightforward scoring schemes, should be considered for use in the development of a scheme based on the ISS.