Composite Disease Activity Measures

Composite disease activity measures can reflect multiple aspects of RA disease and can provide information regarding treatment response.⁴

These measures may incorporate data from a variety of sources, including physician assessments, laboratory values, and patient report.¹

Composite disease activity measures requiring physician assessment

* HAQ is most commonly employed as patient measure of physical function.

Details of composite measures

Measurements of disease remission

While different remission assessment tools may be applied depending on the patient context, EULAR and ACR have established consensus on definitions of disease remission in RA.^2,9

Summary—DAS28 remission^7,9

• Remission defined as DAS28-ESR/CRP <2.6
• Measures SJC, TJC, PtGA, and an acute phase reactant
• Index-based
• May not predict good outcomes as well as lower thresholds or other index measures

Summary—SDAI remission⁷

• Remission defined as ≤3.3
• Measures SJC, TJC, PhGA, PtGA, and an acute phase reactant
• Index-based
• Utility in both clinical trials and practice

Summary—CDAI remission⁷

• Remission defined as ≤2.8
• Measures SJC, TJC, PhGA, PtGA
• Index-based
• Utility in clinical trials and practice

Summary—Boolean-based definition of disease remission⁸

• Provides a yes/no evaluation of remission based on achievement of specified thresholds for patient, physician, and laboratory reports
• Achieved when all of the following are met:
    - SJC ≤1
    - TJC ≤1
    - CRP ≤1 mg/dL
    - PtGA ≤1 (on a 0-10 scale)
• A score that omits CRP has also been validated and may be easier to use in clinical practice

Radiographic progression

Radiographic outcomes are an important component of measuring treatment efficacy, with better radiographic outcomes associated with disease remission.^2,9,10

Assessing radiographic progression can help to establish the impact of treatment on the functional impairment and structural damage associated with RA.¹⁰

PROs are an important tool for evaluating the patient’s experience of disease and treatment.¹³

While PROs may have some limitations, they have been validated in RA to reflect changes in disease activity over time.²

ACR, American College of Rheumatology; CDAI, Clinical Disease Activity Index; CRP, C-reactive protein; DA, disease activity; DAS, Disease Activity Score; DAS28; Disease Activity Score in 28 joints; DMARD, disease-modifying antirheumatic drug; ESR, erythrocyte sedimentation rate; EULAR, European Alliance of Associations for Rheumatology; HAQ, Health Assessment Questionnaire; mTSS, modified Total Sharp Score; PhGA, physician global assessment; PRO, patient-reported outcome; PtGA, patient global assessment; RA, rheumatoid arthritis; SDAI, Simplified Disease Activity Index; SJC, swollen joint count; TJC, tender joint count; VAS, visual analogue scale.

REFERENCES

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