Measure of Intermittent and Constant Osteoarthritis Pain
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Measure of Intermittent and Constant Osteoarthritis Pain

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Purpose

The ICOAP is an 11-item measure that assesses pain in individuals with hip or knee osteoarthritis taking into account both constant and intermittent pain experiences.

Link to Instrument

Instrument Details

Acronym ICOAP

Area of Assessment

Pain
Quality of Life

Assessment Type

Patient Reported Outcomes

Administration Mode

Paper & Pencil

Cost

Free

Diagnosis/Conditions

  • Arthritis + Joint Conditions
  • Pain Management

Populations

Osteoarthritis

Key Descriptions

  • 11-item tool with 2 versions: one to assess pain at knee joint and one to assess pain at hip joint.
  • Scores:
    1) Constant pain subscale ranges from 0-20
    2) Intermittent pain subscale ranges from 0-24
    3) Total pain score ranges from 0-44
  • The 11 items are scored from 0-4 with 0 being no pain and 4 being extreme pain.
  • Items 1-5 assess Constant pain and 6-11 assesses Intermittent pain.
  • Maximum score = 100.

Number of Items

11

Equipment Required

  • Pen/pencil
  • Telephone
  • 11-item questionnaire

Time to Administer

10 minutes

Required Training

No Training

Age Ranges

Adult

18 - 64

years

Elderly Adult

65 +

years

Instrument Reviewers

Initially reviewed by Vaidehi Datar, PT, MHS.

Body Part

Lower Extremity

ICF Domain

Body Structure
Body Function

Measurement Domain

Motor
Sensory

Considerations

  • The ICOAP Knee is a multidimensional osteoarthritis -specific measure designed to evaluate the pain experience in people with knee OA, including pain intensity, frequency, and impact on mood, sleep, and quality of life, independent of the effect of pain on physical function. It includes evaluation of two distinct types of pain: "Constant pain" and "Intermittent pain" that were identified by people with OA as important.
  • Several authors report that the measure is intended to be used with a measure of physical disability.
  • A Rasch analysis was also performed and the results supported the use of Constant and Intermittent subscales as one-dimensional measures of pain (Moreton et al., 2012; n = 175).
  • The ICOAP has been found to be responsive to changes in OA pain in response to pharmacologic interventions and joint replacement surgery with good reliability and validity.
  • The ICOAP scores have been translated and cross-cultural validated in Czech, Dutch, French (France), German, Italian, Norwegian, Spanish (Castilian), North and Central American Spanish, Swedish (Maillefert et al., 2009).
  • The measure was also translated into Portuguese, Greek, Romanian and Russian as reported by a study. However, very few have been evaluated for validity, reliability and responsiveness (Hawker, Mian, Kenzerska, & French, 2011).
  • The measure is endorsed by OARSI/OMERACT Initiative (Hawker, Mian, Kenzerska, & French, 2011).

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Osteoarthritis

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Minimal Detectable Change (MDC)

Patients with Hip or Knee OA: (Singh, 2014; n = 195; 141 knee OA patients and 54 hip OA patients) 

  • MDC for pain: 46.6
  • MDC for constant pain: 49.6 
  • MDC for intermittent pain: 50.8

Minimally Clinically Important Difference (MCID)

Patients with Hip or Knee OA (Singh, 2014) 

 

MCID for total pain:

  • Moderate improvement (“great deal better”) = -26.7
  • Improvement (“somewhat better”) = -18.5 

 

MCID for constant pain: 

  • Moderate improvement (“great deal better”) = -29.6
  • Improvement (“somewhat better”) = - 18.7 

 

MCID for intermittent pain: 

  • Moderate improvement (“great deal better”) = -24.3
  • Improvement (“somewhat better”) = -18.4

Test/Retest Reliability

Patients with Hip or Knee OA (Singh, 2014)

  • Excellent test-retest reliability (ICC = 0.86) in patients with hip OA
  • Adequate test-retest reliability (ICC=0.63) in patients with knee OA

 

Patients with Hip or Knee OA (Hawker et al, 2008)

  • Excellent test-retest reliability (ICC=0.85)

Interrater/Intrarater Reliability

Patients with Hip and Knee OA  (Bombardier et al, 1995; n = 76, age ≥ 40 years)

  • Excellent inter-rater/intra-rater reliability (ICC = 0.85)

 

Patients with Hip and Knee OA (Manolarakis et al, 2016; n = 89, mean age = 71.07; with 2 treatment cycles of 4 intra-articular injections of sodium hyaluronate for the OA pain)

  • Excellent test-retest reliability (ICC > 0.75)

Internal Consistency

Patients with Hip and Knee OA (Hawker et al, 2008)

  • Excellent internal consistency (Cronbach's alpha = 0.93) 

 

Patients with Hip and Knee OA (Manolarakis et al, 2016)

  • Excellent internal consistency for ICOAP Constant pain and Intermittent pain (Cronbach’s alpha > 0.9)
  • Excellent internal consistency for ICOAP Total pain (Cronbach’s alpha = 0.878)

Construct Validity

Patients with Hip and Knee OA (Hawker et al, 2008) descriptive analyses of items demonstrated good distribution of response options across all items.

  • Excellent correlation with scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scale (r = 0.81)
  • Excellent correlation with scores on the Knee Injury and OA Outcome Score (KOOS) symptoms scale (r = 0.60)

Content Validity

Patients with Hip and Knee OA (Hawker et al, 2008) 

  • Content and face validity were determined through focus groups used to develop the ICOAP.

 

Patients with Hip and Knee OA (Manolarakis et al, 2016)

  • Content validity advocated by comparing ICOAP to the standard SF-36 Health Survey.

Face Validity

Patients with Hip and Knee OA (Hawker et al, 2008) 

  • Content and face validity were determined through focus groups used to develop the ICOAP.

Floor/Ceiling Effects

Patients with Knee OA (Gonçalves et al, 2012; n = 109; age> 50unilateral or bilateral severe Knee OA validated according to clinical and radiological criteria of American College of Rheumatology)

  • Adequate floor effects < 20% for Constant pain subscale (Floor effects = 6.4%) 
  • Adequate floor effects < 20% for Intermittent pain subscale  (Floor effects = 0.9%) 

Floor effects were considered to be present when more than 15% of the patients received the lowest possible score on pre-treatment ICOAP subscales and total pain.

 

Patients with Knee OA (Gonçalves et al, 2012)

  • Adequate ceiling effects < 20% for Constant pain subscale (Ceiling effects= 1.8)
  • Adequate ceiling effects < 20% for Intermittent pain subscale (Ceiling effects= 1.8)

Ceiling effects were considered to be present when more than 15% of the patients received the highest possible score on pre-treatment ICOAP subscales and total pain score

Responsiveness

Patients with Knee OA (Gonçalves et al, 2012)

  • Moderately responsive within 4 weeks of physical therapy with 55 (55.5%) patients reported at least moderate improvement (score higher or equal to 4) on the Global Rating Change Scale (GRCS).

Bibliography

Bombardier, C., Melfi, C., Paul, J., Green, R., Hawker, G., Wright, J., & Coyote, P. (1995). Comparison of a generic and a disease-specific measure of pain and physical function after knee replacement surgery. Med Care, 33(4), 131-144.

Gonçalves, R., Meireles, A., Gil, J., Cavalheiro, L., Rosado, J., & Cabri, J. (2012). Responsiveness of intermittent and constant osteoarthritis pain (ICOAP) after physical therapy for knee osteoarthritis. Osteoarthritis and Cartilage, 20(10), 1116-1119.

Hawker, G., Davis, A., French, M., Cibere, J., Jordan, J., March, L., . . . Dieppe, P. (2008). Development and preliminary psychometric testing of a new OA pain measure – an OARSI/OMERACT initiative. Osteoarthritis and Cartilage, 16(4), 409-414.

Hawker GA, Mian S, Kendzerska T, French M. (2011). Measures of adult pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36). Arthritis Care Res Arthritis Care & Research, 63(S11).

Manolarakis GE, Kontodimopoulos N, Sifaki-Pistolla D, Niakas D. (2016). Establishing the Psychometric Properties of the ICOAP Questionnaire through Intra-Articular Treatment of Osteoarthritic Pain: Implementation for the Greek Version. Arthritis 2016;1–11.

Maillefert, J., Kloppenburg, M., Fernandes, L., Punzi, L., Günther, K., Mola, E. M., . . . Hawker, G. (2009). Multi-language translation and cross-cultural adaptation of the OARSI/OMERACT measure of intermittent and constant osteoarthritis pain (ICOAP). Osteoarthritis and Cartilage, 17(10), 1293-1296.

Moreton, B., Wheeler, M., Walsh, D., & Lincoln, N. (2012). Rasch analysis of the intermittent and constant osteoarthritis pain (ICOAP) scale. Osteoarthritis and Cartilage, 20(10), 1109-1115.

Singh, J. A., Luo, R., Landon, G. C., & Suarez-Almazor, M. (2014). Reliability and Clinically Important Improvement Thresholds for Osteoarthritis Pain and Function Scales: A Multicenter Study. The Journal of Rheumatology, 41(3), 509-515.

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