Development and Validation of the PatientDevelopment and Validation of the PatientDevelopment and Validation of the PatientDevelopment and Validation of the Patient----Reported ImpactReported ImpactReported ImpactReported Impact of Scars Measure (PRISM)of Scars Measure (PRISM)of Scars Measure (PRISM)of Scars Measure (PRISM)

Wilburn J1, McKenna SP1, Brown BC2, Solomon M2, McGrouther DA2, Bayat A2 1Galen Research, Manchester, UK; 2University of Manchester, Manchester, UK

PRISM is the first scientifically rigorous patient-reported instrument de-

signed specifically for scar patients. It consists of two unidimensional

scales with good psychometric and scaling properties: QoL (24 items)

and symptoms (13 items).

PRISM is well accepted by patients, easy to use and should prove valu-

able for assessing scar-related symptoms and QoL in clinical trials and

practice.

All wounds leave scars unless they are very small or superficial. Over

100,000,000 people acquire post-surgical scars each year worldwide.1

• Western societies value physical perfection, therefore, scars can

cause significant psychosocial disability.2,3

• Up to half of patients with disfiguring conditions suffer anxiety, social

avoidance and impairment of quality of life (QoL).4

• Several instruments are available to quantify the distress caused by

general dermatological5,6 or disfiguring conditions.7

• These generic instruments are not specific to scars and are less sen-

sitive than disease-specific measures.8,9

• No scientifically sound scar-specific measure exists.

Patients were recruited through a specialist service at a plastic surgery

clinic in Manchester, UK.

Item generation

• Qualitative interviews conducted with scar patients were recorded

and transcripts produced.

• Thematic content analysis conducted to identify key areas of impact.

• Draft questionnaire produced.

Cognitive Debriefing Interviews

• Semi-structured interviews conducted with patients to assess face

and content validity.

Validation survey

• Test-retest validation survey conducted.

• PRISM and a demographic questionnaire completed.

• Clinician-assessed scar severity rated from 5 (good) to 28 (poor) us-

ing the Manchester Scar Scale (MSS).10

Item reduction / scaling assessment

• Rasch analysis (one-parameter logistic item response theory)11 ap-

plied to PRISM data.

• Items displaying misfit, redundancy or differential item functioning

(DIF) were removed.

Assessment of psychometric properties

• Internal consistency assessed using Cronbach’s Alpha.

• Test-retest reliability calculated.

• Known groups validity was examined by relating PRISM scores to

self-perceived severity, self-perceived general health and MSS

scores.

• Convergent validity was examined by correlating the PRISM with the

Hospital Anxiety and Depression Scale (HADS)12 and the General

Well-Being Index (GWBI).13

Results

Conclusions

Methods

Table 1: Participant’s details

Qualitative Interviews

n=34

Cognitive Debriefing

n=16

Validation Survey n=103

Demographic details

% Female 70.6 62.5 67.0

Mean Age (SD) 35.7 (17.9) 32.8 (17.4) 35.5 (15.0)

% Married 13.9 31.3 31.1

% Employed 41.1 43.7 52.4

Scar details

% Visible 47.3 62.5 51.5

Time since scarring (SD) years

8.4 (10.0) 6.1 (7.1) 6.8 (7.3)

Scar Type (%)

Keloid Stretched Hypertrophic Depressed Normal

38.2 8.8 14.7 8.8 29.4

31.2 18.8 31.2 6.2 12.5

41.7 31.1 17.5 2.9 5.8

Item generation 567 potential items were extracted from 34 transcripts. These interviews

revealed two key areas of impact; physical symptoms and QoL. After

review and reduction, a draft PRISM was produced containing 16 symp-

tom and 36 QoL items.

Cognitive debriefing interviews All 16 patients were able to respond to every item and generally found

the measure relevant and easy to understand. Two items were removed

from the QoL scale because they were considered too extreme by par-

ticipants.

Validation survey Table 1 presents demographic details of the validation survey. 103 pa-

tients participated, 51 of whom completed the measures on two occa-

sions to assess reproducibility. High scores on all measures represent

worse health states or QoL.

• Three items were removed from the symptom scale;

- One misfit the Rasch model

- Two were redundant

- The final scales both fit the Rasch model.

• Ten items were removed from the QoL scale;

- Seven misfit the Rasch model

- Two were redundant

- One demonstrated DIF by age (‘I avoid going to places that are

brightly lit’).

• Each scale demonstrated unidimensionality, indicating measurement

of one concept only.

• Internal consistency was good for the symptoms (0.85) and QoL

(0.93) scale.

• Reproducibility was adequate for the symptom scale (0.83) and good

for the QoL scale (0.89).

• There were no significant differences in QoL or Symptom scores re-

lated to age or gender.

• There were relatively low correlations between the QoL scale and the

comparator instruments (HADS & GWBI) (Table 2).

• There were moderate correlations between the symptoms scale and

the comparator measures. The symptom scale differentiated be-

tween scores on the HADS scales and the clinician-completed MSS,

but not patient-reported scar severity. The QoL scale differentiated

between scores on all four comparator scales.

Contact details Jeanette Wilburn, Research Associate, Galen Research Ltd, En-

terprise House, Manchester Science Park, Lloyd Street North, Man-

chester, M15 6SE, UK.

Tel: +44 (0)161 226 4446

Email: jwilburn@galen-research.com

Table 2: Correlations between PRISM scales and HADS and GWBI

HADS Anxiety HADS Depression GWBI

Symptom 0.21* 0.22* 0.37**

QoL 0.55** 0.51** 0.63**

Interview Quotes “I’d never do a job when I have to deal with peo-ple face to face like in a shop or something like that because I just couldn’t stand it at all” “If I go out I’ll go out in the middle of the night or dead early in the morning when there’s no-one around” “It’s affected me in a big way in terms of my abil-ity to form relationships and not just intimate re-lationships but relationships in general”

**p< 0.01 (2-tailed) *p< 0.05 (2-tailed)

Figure 1: QoL scores by self-perceived scar severity (p<0.01)

Figure 3: QoL scores by MSS score (p<0.05)

• To develop and validate the first scar-specific PRO measure.

The Patient-Reported Impact of Scars Measure (PRISM) contains

two scales: Symptoms and QoL. This poster describes the develop-

ment and validation of the PRISM.

Stretched scar Keloid scar

Aim

References

[1] Sund B. New developments in wound care. London: PJB Publications, 2000:1-255. (Clinica Reprt CBS 836). [2] Beuf AH. Beauty is the beast: appearance-impaired children in America. Philadelphia: University of Pennsylvania Press; 1990. [3] Thompson TK, Heinberg LJ, Altabe M, Tantleff-Dunn S. Exacting beauty: theory, assessment, and treatment of body image disturbance. Washington, DC: American Psychological Association; 1999. [4] Rumsey N, Clarke A, Musa M. Altered body im-age: the psychosocial needs of patients. Br J Community Nurs. 2002;7(11):563-6. [5] Chren MM, Lasek RJ, Quinn LM, Mostow EN, Zyzanski SJ. Skindex, a quality-of-life measure for patients with skin disease: reliability, validity, and responsiveness. J In-vest Dermatol. 1996;107(5):707-13. [6] Finlay AY, Khan GK: Dermatology Life Quality Index (DLQI)—A simple practical meas-ure for routine clinical use. Clin Exp Dermatol. 1994:210–216. [7] Harris DL, Carr AT. The Derriford appearance scale (DAS59): a new psychometric scale for the evaluation of patients with disfigurements and aesthetic problems of appearance. Br J Plast Surg. 2001;54:216e22. [8] Bradley C. Importance of differentiating health status from quality of life. Lancet. 2001;357(9249):7-8. [9] Ritva K, Pekka R, Harri S. Agreement between a generic and disease-specific quality-of-life instrument: the 15D and the SGRQ in asthmatic patients. Qual Life Res. 2000;9(9):997-1003. [10] Rasch G. Probabilistic Models for some Intelligence and Attainment Tests. Chicago: University of Chicago Press, 1980. [11] Beausang E et al. A new quantitative scale for clinical scar assessment. Plast Reconstr Surg 1998; 102:1954-61. [12] Zigmond AS, Snaith RP. The Hospital Anxiety and Depression Scale. Acta Psychiatr Scand 1983, 67:361-70. [13] Hunt, SM, McKenna, SP. A British adaptation of the General Well-Being In-dex: a new tool for clinical research. British Journal of Medical Economics 1992, 2:49-60.

Figure 2: Symptom scores by MSS score (p<0.01)

0

2

4

6

8

10

12

14

16

Self-perceived scar severity

Mean

Qo

L S

co

re

Very good

Good

Fair

Poor

Very Poor

0

2

4

6

8

10

12

MSS Scores

Mean

Qo

L S

co

re

< 14

≥ 14 AND ≤17

> 17

0

1

2

3

4

5

MSS Scores

Mean

Sym

pto

m S

co

re

< 14

≥ 14 AND ≤17

> 17

Background