A self-report Thompson articular index: what does it measure?

Area of Science:

• Rheumatology
• Clinical Assessment
• Patient-Reported Outcomes

Background:

• Rheumatoid arthritis (RA) management requires accurate joint assessment.
• The Thompson articular index (ThAI) is used to evaluate joint involvement.
• Assessing the reliability and validity of patient self-reported measures is crucial for clinical utility.

Purpose of the Study:

• To evaluate the reliability and validity of the self-report Thompson articular index (ThAI) in Dutch rheumatoid arthritis (RA) patients.
• To compare patient-assessed ThAI scores with rheumatologist-assessed scores.
• To determine the correlation of ThAI scores with clinical and laboratory markers of RA disease activity.

Main Methods:

• 43 RA patients completed the self-report ThAI and AIMS-2 questionnaire.
• A rheumatologist independently assessed the ThAI in the same patients.
• Test-retest reliability was assessed after 4 weeks.
• Erythrocyte sedimentation rate (ESR) was measured.
• Agreement and correlation analyses were performed.

Main Results:

• The self-report ThAI demonstrated adequate test-retest reliability (ICC=0.83).
• Low agreement was found between patient and rheumatologist ThAI scores (ICC=0.44), with patient scores being significantly higher.
• Rheumatologist scores correlated with ESR and physical function, while patient scores correlated with physical function, pain, and mood.
• Patient self-reported joint involvement was more strongly related to physical function than to objective measures of disease activity like ESR.

Conclusions:

• The self-report ThAI is a reliable tool for RA patients.
• The validity of the self-report ThAI is questionable due to poor agreement with rheumatologist assessments and weak correlation with ESR.
• Self-reported joint involvement in RA appears more influenced by physical function and pain perception than by underlying inflammatory activity.