Chronic Pain Grade Scale

Last Updated

July 22, 2020

Purpose

The Chronic Pain Grade Scale (CPGS), also referred to as the Chronic Pain Grade Questionnaire, is a 7-item objective measure designed to evaluate pain intensity and pain-related disability in adults with chronic pain conditions.

Acronym CPGS, CPG

Area of Assessment

Pain
Life Participation
Quality of Life
General Health

Assessment Type

Patient Reported Outcomes

Administration Mode

Paper & Pencil

Cost

Not Free

Actual Cost

$0.00

Cost Description

Cost of Materials

CDE Status

Not a CDE (7/24/2020)

Chronic Pain

7-item self-report questionnaire, 0-10 Likert scale
3 subscales are scored to describe 2 dimensions of chronic pain over the past 3-6 months: Pain intensity (characteristic pain intensity) and pain-related disability (disability score; disability points score)
Characteristic pain intensity score and disability score range from 0-100; Disability score and disability days are used to calculate disability points score, which ranges from 0-3
Scores are used to classify chronic pain severity on a 0-IV scale: Grade 0 (no pain), Grade I (low disability-low intensity), Grade II (low disability-high intensity), grade III (high disability-moderately limiting) and grade IV (high disability-severely limiting)

Number of Items

Paper survey
Writing utensil

2-10 minutes

Average completion time is 3-4 minutes.

Required Training

No Training

Required Training Description

Should be administered by a trained health care professional.

Adult

18 - 64

years

Older Adult

65 - 100

years

Instrument Reviewers

Jennifer Burns; Ashley Lea, Sophie Quigg, Cayla Faverio, Colton Phelps, Michael Losensky (Duke Doctor of Physical Therapy Students); Derek Clewley, PT, DPT, PhD (faculty)

Body Part

Head
Back
Neck
Upper Extremity
Lower Extremity

ICF Domain

Participation
Activity
Body Function
Body Structure

Measurement Domain

Participation & Activities
General Health

Considerations

Cognitive status, Level of understanding

Normative Data

Chronic Pain: (Von Korff, 1992; n = 2389 [n = 1213 back pain, n = 779 headache, n = 397 temporomandibular disorder {TMD}]; Age Range = 18-75 years)

Pain Grade	Back pain (n, %)	Headache (n, %)	TMD pain (n, %)
Grade I	414, 34.9%	229, 29.7%	159, 40.7%
Grade II	330, 27.9%	309, 40.1%	170, 43.5%
Grade III	237, 20%	156, 20.2%	41, 10.5%
Grade IV	204, 17.2%	77, 10%	21, 5.4%
Missing	28	8	6

Chronic Musculoskeletal Pain: (Salaffi et al. 2006; n = 576; Mean Age (SD) = 61.5 (13.5) years; Italian sample; Italian version of CPG)

Mean (SD) scores on the CPG items:
- Mean current pain intensity = 4.90 (2.18)
- Mean average pain intensity in the past 6 months = 5.21 (1.93)
- Worst pain intensity in the past 6 months = 6.40 (2.14)
- Mean level of interference of musculoskeletal pain with daily activities = 3.97 (2.56)
- Mean level of interference of musculoskeletal pain with recreational, social, and family activities = 3.56 (2.70)
- Mean level of interference of musculoskeletal pain with work/housework = 3.77 (2.76)

Chronic Pain in Emergency Department: (Bernard, 2004; n = 476, Mean Age = 43.4 (16.3) years; Emergency Department patients reporting chronic pain)

Grade 0 (null); Grade I (null); Grade II (n = 19, 9.8%); Grade III (n = 62, 32.1%); Grade IV (n = 69, 35.8%)

Chronic Upper Extremity Pain: (Roy, 2012; n = 448, Mean Age = 45 (10) years; Mean symptom duration = 22 (55) months; Work-related upper-extremity injury resulting in disability)

At baseline (n=557): Grade 0 (null), Grade I (n=28, 5%), Grade II (n=39, 7%), Grade II (n=101, 18%), Grade IV (n=389, 70%)
At follow-up visit (+6 months, n=448): Grade 0 (n=2, 0.4%), Grade I (n=55, 11%), Grade II (n=40, 8%), Grade III (n=61, 12%), Grade IV (n=340, 68%)

Test/Retest Reliability

Chronic Low Back Pain: (Dunn, 2003; n = 259; Mean Age = 45 (8.1) years; UK sample)

Moderate test-retest reliability after 2-weeks (weighted kappa = 0.81 for chronological questionnaire and = 0.60 for traditional questionnaire)

Internal Consistency

Chronic Back Pain: (Von Korff, 1992)

Adequate internal consistency (Cronbach’s alpha = 0.74)

Chronic Pain: (Smith, 1997; n = 293; Scottish sample)

Excellent internal consistency (Cronbach's alpha = 0.91)
High item-total correlations:
- Question #1: 0.7085
- Question #2: 0.6885
- Question #3: 0.7673
- Question #4: 0.6951
- Question #5: 0.8285
- Question #6: 0.8291
- Question #7: 0.8061

Chronic Musculoskeletal Pain: (Salaffi, 2006; n = 576; Mean Age (SD) = 61.5 (13.5) years; Italian sample, Italian version of CPGS)

Good internal consistency (Cronbach’s alpha = 0.89 for Disability Score; = 0.81 for characteristic pain intensity)
Significant correlation between the pain and disability dimensions of CPG (Spearman’s rho = 0.48)
Moderate to high item-total correlations
- Highest item-total correlation for item 7 (r=0.77)
- Lowest item-total correlation for
- item 1 (r=0.50)

Chronic Hip Pain: (Papaioannou, 2018; n = 87; Mean Age = 67 (9.34) years; Greek sample, Greek translation [CPGQ-Gr])

Excellent internal consistency for total scale, disability scale, and chronic pain intensity (Cronbach’s alpha = 0.90, 0.95, 0.83 respectively) (ICC = 0.84, 0.92, 0.91 respectively)

Criterion Validity (Predictive/Concurrent)

Chronic Upper Extremity: (Roy, 2012)

No significant predictive validity for CPG Grades on the probability of work productivity loss, work instability, or outcomes of upper-extremity disability after 6 months.

Construct Validity

Chronic Pain: (Smith, 1997)

“All seven questions included in this analysis had a factor loading greater than 0.75…therefore all contributed substantially to the variance explained by this factor. Since the CPG was designed to measure a single concept, i.e., pain, it appeared reasonable that only one factor represented most of the variance between patients.”
Factor analysis values:
- Question #1: 0.7808
- Question #2: 0.7677
- Question #3: 0.8302
- Question #4: 0.7691
- Question #5: 0.8866
- Question #6: 0.8843
- Question #7: 0.8652
Adequate convergent validity between the Pain dimension of the SF-36 and the CPGS Pain Intensity Score (Spearman’s correlation coefficient = -0.71); Disability points score ( = -0.71) and Chronic Pain Grade (= -0.84)
Highly significant correlation between the CPGS and all eight dimensions of the SF-36 (Spearman’s correlation coefficients range from -0.28 to -0.84, p<0.001)

Chronic Pain: (Penny, 1999; n = 6940 [n = 3605 general population, n = 3335 repeat prescription]; UK sample)

Significant convergent validity between SF-36 and CPGS such that higher CPG correlates with lower mean scores for all eight SF-36 subscales (p<0.001 for eight Kruskal-Wallis Tests)
Significant convergent validity between Glasgow Pain Questionnaire (GPQ) and CPGS such that higher CPG correlates with higher mean scores for all five GPQ dimensions (p<0.001 for five Kruskal-Wallis Tests)

Chronic Musculoskeletal Pain: (Salaffi, 2006)

Convergent validity

Significant convergent validity between CPGS and all SF-36 subscales measuring pain and physical health:
- Characteristic Pain Intensity subscale and SF-36 Bodily Pain subscale (Spearman’s rho = -0.55, p<0.0001)
- Disability Score subscale and SF-36 Physical Component Summary Scale Score (PCS) dimension (= -0.62, p<0.0001)
Significant convergent validity between CPGS Grade and presence of comorbid conditions (Chi squared = 36.37)
Significant convergent validity between CPGS Grade and older age (Chi squared = 64.34)

Discriminant validity

Significant discriminant validity between CPGS and SF-36 subscales measuring mental health:
- CPGS Characteristic Pain Intensity, CPGS Disability Score and SF-36 Mental Health subscale (= -0.28, -0.39 respectively)

Chronic Upper Extremity Pain: (Roy, 2012)

Significant discriminant validity of CPGS on different levels of disability and work status after 6 months as indicated by significantly poorer scores (P<0.008) on the QuickDASH, WLQ-25, and RA-WIS for higher Grades (IV, III) versus lower Grades (I, II)

Responsiveness

Chronic Musculoskeletal Pain: (Elliott, 2000; n = 450; Scottish sample)

Significant correlations between change in CPG and change in multiple SF-36 subscales: Physical functioning (-0.29), Social Functioning (-0.32), Role Physical (-0.34), Bodily Pain (-0.42), General Health (-0.28).

Chronic Musculoskeletal Pain: (Hawker, 2011)

Moderate responsiveness after 12 months of treatment in Pain Intensity and Disability subscales (standardized effect size = 0.41, 0.43 respectively)

Bibliography

Bernard, AM, Wright, SW. Chronic Pain in the ED. American Journal of Emergency Medicine, 2004; 22(6): 444-7.

Dunn KM, Jordan K, Croft PR. Does questionnaire structure influence response in postal surveys? J Clin Epidemiol 2003; 56: 10-6.

Elliot AM, Smith BH, Smith WC, Chambers WA. Changes in chronic pain severity over time: the Chronic Pain Grade as a valid measure. Pain, 2000; 88: 303-8.

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 bps), and measure of intermittent and constant osteoarthritis pain (icoap). Arthritis Care & Research, 2011; 63(S11): 240-252.

Papaioannou, M, Diakomi, M, Georgoudis, G, Argyra, E, Vadalouca, A, Siafaka, I. The Chronic Pain Grade Questionnaire: validity, reliability, and responsiveness in Greek chronic hip pain sufferers. Hippokratia, 2018; 22(1): 37-42.

Penny KI, Purves AM, Smith BH, Chambers WA, Smith WC. Relationship between the chronic pain grade and measure of physical, social and psychological well-being. Pain, 1999; 79: 275-9.

Roy, JS, MacDermid, JC, Tang, K, Beaton, DE. Construct and Predictive Validity of the Chronic Pain Grade in Workers with Chronic Work-related Upper-extremity Disorders. The Clinical Journal of Pain, 2013; 29(10): 891-897.

Salaffi F, Stancati A, Grassi W. Reliability and validity of the Italian version of the Chronic Pain Grade questionnaire in patients with musculoskeletal disorders. Clin Rheumatol. 2006; 25(5): 619-31.

Smith BH, Penny KI, Purves AM, et al. The Chronic Pain Grade questionnaire: validation and reliability in postal research. Pain, 1997; 71(2):141-7.

Von Korff M, Ormel J, Keefe FJ, Dworkin SF. Grading the severity of chronic pain. Pain, 1992; 50: 133-49.