Rheumatoid Arthritis

Clinical Outcome Measures in RA

Measures

RA clinical outcome measures are critical to the evaluation of treatment efficacy and support treat-to-target strategies that improve patient outcomes.1,2

 

A variety of measures are available that can be used to assess various aspects of the disease and help to inform treatment decisions.2

Different clinical outcome measures can be employed depending on informational needs and patient context.1,3

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

Endpoint

ACR response criteria2,4,5

Description

Represents a relative change in disease activity from baseline

Score

Based on average percentage improvement in core measures of disease activity, including patient, physician, and laboratory reports

Attributes

  • Reduces outcome reporting to one measure
  • Used in most studies, facilitating comparisons between drugs
  • Sensitive to change
  • Response measure, reflects change in disease over time

Endpoint

DAS28-ESR/CRP7

Description

Measures disease activity using patient, physician, and laboratory reports

Score

Attributes

  • Excellent reliability, responsiveness, and validity
  • Remission criteria are less conservative than for other measures (including CDAI and SDAI)
  • Weighs the components, making calculation more complex

Endpoint

CDAI7

Description

Measures disease activity using patient and physician reports

Score

Attributes

  • Excellent responsiveness and validity
  • Depends on performing joint counts reliably and consistently
  • Simple score addition; no weighted components requiring calculators
  • Independent of laboratory biomarkers

Endpoint

SDAI2,7

Description

Measures disease activity using patient, physician, and laboratory reports

Score

Attributes

  • Excellent responsiveness and validity
  • Most sensitive and specific predictor for clinical decisions on switching DMARDs
  • Simple score addition; no weighted components requiring calculators
  • Not a measure of change over time

Endpoint

Boolean-based definition of disease remission8

Description

Measures disease activity using patient, physician, and laboratory reports

Score

Achieved or not achieved

Attributes

  • Easier to use in clinical practice because does not require an acute-phase reactant
  • Dichotomy provides less information than score of a continuum
 
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 remission7,9
  • 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

Endpoint

mTSS11,12

Description

Examines radiographic progression of RA (in hands, wrists, and feet)

Score

Range: variable based on number of joints examined and scaling system

Higher score indicates more joint destruction

Attributes

  • More sensitive than the Genant/Sharp and Larsen scores
  • Relatively more tedious to use
  • Shows treatment effect on radiographic progression
  • Baseline score can predict joint damage progression

PROs

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

Endpoint

HAQ14,15

Description

Examines patient’s functional ability across 8 domains (dressing, rising, eating, walking, maintaining hygiene, reaching, gripping, and performing other usual activities) using a self-administed questionnaire

Score

Range: 0-3

Higher score means more functional disability

Attributes

  • Reliable and valid across many formats (e.g., mail, phone, in-office)
  • Sensitive to early changes
  • Correlates with:

    - Other self-report measures (e.g., Beck Depression
      Scale, DAS)
    - Clinical measures (e.g., joint/muscle activity, bone
      health)
    - Biochemical measures (e.g., CRP)
    - Mortality
    - Patient-perceived risk of work instability 

Endpoint

PAIN VAS16

Description

Examines patient’s level of pain using a VAS

Score

Range: 0-100 mm

Higher score indicates greater pain intensity

Minimal clinically significant change: 11

Attributes

  • Adaptable to many settings
  • Vertical VAS tends to have higher scores than horizontal VAS, so consistency is recommended
  • Simple to calculate; only need a ruler
  • May be difficult for older patients with cognitive or motor impairment

Related

Treatment Guidelines

Explore treatment guidelines for patients with RA

PROs

Explore and learn more about patient-reported outcomes

Discover our product information for rheumatoid arthritis

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

1. England BR, Tiong BK, Bergman MJ, et al. Arthritis Care Res (Hoboken). 2019;71(12):1540-1555. 2. Salomon-Escoto K, Kay J. Rheum Dis Clin North Am. 2019;45(4):487-504. 3. Kirkham JJ, Boers M, Tugwell P, Clarke M, Williamson PR. Trials. 2013;14:324. 4. Ranganath VK, Yoon J, Khanna D, et al. Ann Rheum Dis. 2007;66(12):1633-1640. 5. Felson DT, LaValley MP. Arthritis Res Ther. 2014;16(1):101. 6. Landewé RBM, van der Heijde D. Ann Rheum Dis. 2020;annrheumdis-2020-216999. 7. Anderson J, Caplan L, Yazdany J, et al. Arthritis Care Res (Hoboken). 2012;64(5):640-647. 8. Felson DT, Smolen JS, Wells G, et al. Ann Rheum Dis. 2011;70(3):404-413. 9. Felson D. Ann Rheum Dis. 2012;71 Suppl 2(0 2):i86-i88. 10. Combe B, Lula S, Boone C, Durez P. Clin Exp Rheumatol. 2018;36(4):658-667. 11. Ory PA. Ann Rheum Dis. 2003;62(7):597-604. 12. Landewé RB, Connell CA, Bradley JD, et al. Arthritis Res Ther. 2016;18(1):212. 13. Fautrel B, Alten R, Kirkham B, et al. Rheumatol Int. 2018;38(6):935-947. 14. Bruce B, Fries JF. Clin Exp Rheumatol. 2005;23(5 Suppl 39):S14-S18. 15. Macedo A, Oakley S, Gullick N, Kirkham B. J Rheumatol. 2009;36(2):225-230. 16. Hawker GA, Mian S, Kendzerska T, French M. Arthritis Care Res (Hoboken). 2011;63 Suppl 11:S240-S252.