Skip to main content
NCBI home page
Annals of the Rheumatic Diseases logoLink to Annals of the Rheumatic Diseases
. 2004 Jan;63(1):36–42. doi: 10.1136/ard.2002.001784

Satisfactory cross cultural equivalence of the Dutch WOMAC in patients with hip osteoarthritis waiting for arthroplasty

L Roorda 1, C Jones 1, M Waltz 1, G Lankhorst 1, L Bouter 1, J W van der Eijken 1, W Willems 1, I Heyligers 1, D Voaklander 1, K Kelly 1, M Suarez-Almazor 1
PMCID: PMC1754708  PMID: 14672889

Abstract

Background: Cross cultural validity is of vital importance for international comparisons.

Objective: To investigate the validity of international Dutch-English comparisons when using the Dutch translation of the Western Ontario and McMaster Universities osteoarthritis index (WOMAC).

Patients and Methods: The dimensionality, reliability, construct validity, and cross cultural equivalence of the Dutch WOMAC in Dutch and Canadian patients waiting for primary total hip arthroplasty was investigated. Unidimensionality and cross cultural equivalence was quantified by principal component and Rasch analysis. Intratest reliability was quantified with Cronbach's α, and test-retest reliability with the intraclass correlation coefficient. Construct validity was quantified by correlating sum scores of the Dutch WOMAC, Arthritis Impact Measurement Scales (Dutch AIMS2), Health Assessment Questionnaire (Dutch HAQ), and Harris Hip Score (Dutch HHS).

Results: The WOMAC was completed by 180 Dutch and 244 English speaking Canadian patients. Unidimensionality of the Dutch WOMAC was confirmed by principal component and Rasch analysis (good fit for 20/22 items). The intratest reliability of the Dutch WOMAC for pain and physical functioning was 0.88 and 0.96, whereas the test-retest reliability was 0.77 and 0.92, respectively. Dutch WOMAC pain sum score correlated 0.69 with Dutch HAQ pain, and 0.39 with Dutch HHS pain. Dutch WOMAC physical functioning sum score correlated 0.46 with Dutch AIMS2 mobility, 0.62 with Dutch AIMS2 walking and bending, 0.67 with Dutch HAQ disability, and 0.49 with Dutch HHS function. Differential item functioning (DIF) was shown for 6/22 Dutch items.

Conclusions: The Dutch WOMAC permits valid international Dutch-English comparisons after correction for DIF.

Full Text

The Full Text of this article is available as a PDF (199.4 KB).

Figure 1 .

Figure 1

Open in a new tab

Pain item calibrations for the Dutch WOMAC and the English WOMAC. English calibrations on the x axis, and Dutch on the y axis. Calibrations are expressed in logits. Negative calibrations indicate easier items. Positive calibrations indicate more difficult items. An identity line is drawn through the origin, with a slope of 1. Statistical control lines (95% CI) are drawn around the identity line (dotted lines). The area between the dotted lines depicts acceptable item deviation. Items outside the control lines demonstrate DIF. The numbers near the data points refer to the WOMAC item numbers. For a full explanation of the items see table 1.

Figure 2 .

Figure 2

Open in a new tab

Physical functioning item calibrations for the Dutch WOMAC and the English WOMAC. English calibrations on the x axis, and Dutch on the y axis. Calibrations are expressed in logits. Negative calibrations indicate easier items. Positive calibrations indicate more difficult items. An identity line is drawn through the origin, with a slope of 1. Statistical control lines (95% CI) are drawn around the identity line (dotted lines). The area between the dotted lines depicts acceptable item deviation. Items outside the control lines demonstrate DIF. The numbers near the data points refer to the WOMAC item numbers. For a full explanation of the items see table 1.

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Bae S. C., Lee H. S., Yun H. R., Kim T. H., Yoo D. H., Kim S. Y. Cross-cultural adaptation and validation of Korean Western Ontario and McMaster Universities (WOMAC) and Lequesne osteoarthritis indices for clinical research. Osteoarthritis Cartilage. 2001 Nov;9(8):746–750. doi: 10.1053/joca.2001.0471. [DOI] [PubMed] [Google Scholar]
  2. Beaton D. E., Bombardier C., Guillemin F., Ferraz M. B. Guidelines for the process of cross-cultural adaptation of self-report measures. Spine (Phila Pa 1976) 2000 Dec 15;25(24):3186–3191. doi: 10.1097/00007632-200012150-00014. [DOI] [PubMed] [Google Scholar]
  3. Bellamy N., Kirwan J., Boers M., Brooks P., Strand V., Tugwell P., Altman R., Brandt K., Dougados M., Lequesne M. Recommendations for a core set of outcome measures for future phase III clinical trials in knee, hip, and hand osteoarthritis. Consensus development at OMERACT III. J Rheumatol. 1997 Apr;24(4):799–802. [PubMed] [Google Scholar]
  4. Fries J. F., Spitz P. W., Young D. Y. The dimensions of health outcomes: the health assessment questionnaire, disability and pain scales. J Rheumatol. 1982 Sep-Oct;9(5):789–793. [PubMed] [Google Scholar]
  5. Harris W. H. Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by mold arthroplasty. An end-result study using a new method of result evaluation. J Bone Joint Surg Am. 1969 Jun;51(4):737–755. [PubMed] [Google Scholar]
  6. Jones C. A., Voaklander D. C., Johnston D. W., Suarez-Almazor M. E. Health related quality of life outcomes after total hip and knee arthroplasties in a community based population. J Rheumatol. 2000 Jul;27(7):1745–1752. [PubMed] [Google Scholar]
  7. Kelly K. D., Voaklander D. C., Johnston D. W., Newman S. C., Suarez-Almazor M. E. Change in pain and function while waiting for major joint arthroplasty. J Arthroplasty. 2001 Apr;16(3):351–359. doi: 10.1054/arth.2001.21455. [DOI] [PubMed] [Google Scholar]
  8. Kelly K. D., Voaklander D., Kramer G., Johnston D. W., Redfern L., Suarez-Almazor M. E. The impact of health status on waiting time for major joint arthroplasty. J Arthroplasty. 2000 Oct;15(7):877–883. doi: 10.1054/arth.2000.9061. [DOI] [PubMed] [Google Scholar]
  9. Kelly Karen D., Voaklander Donald C., Johnston William C., Suarez-Almazor Maria E. Equity in waiting times for major joint arthroplasty. Can J Surg. 2002 Aug;45(4):269–276. [PMC free article] [PubMed] [Google Scholar]
  10. Liang M. H. Longitudinal construct validity: establishment of clinical meaning in patient evaluative instruments. Med Care. 2000 Sep;38(9 Suppl):II84–II90. [PubMed] [Google Scholar]
  11. McConnell S., Kolopack P., Davis A. M. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): a review of its utility and measurement properties. Arthritis Rheum. 2001 Oct;45(5):453–461. doi: 10.1002/1529-0131(200110)45:5<453::aid-art365>3.0.co;2-w. [DOI] [PubMed] [Google Scholar]
  12. Meenan R. F., Mason J. H., Anderson J. J., Guccione A. A., Kazis L. E. AIMS2. The content and properties of a revised and expanded Arthritis Impact Measurement Scales Health Status Questionnaire. Arthritis Rheum. 1992 Jan;35(1):1–10. doi: 10.1002/art.1780350102. [DOI] [PubMed] [Google Scholar]
  13. Riemsma R. P., Taal E., Rasker J. J., Houtman P. M., Van Paassen H. C., Wiegman O. Evaluation of a Dutch version of the AIMS2 for patients with rheumatoid arthritis. Br J Rheumatol. 1996 Aug;35(8):755–760. doi: 10.1093/rheumatology/35.8.755. [DOI] [PubMed] [Google Scholar]
  14. Rojkovich B., Gibson T. Day and night pain measurement in rheumatoid arthritis. Ann Rheum Dis. 1998 Jul;57(7):434–436. doi: 10.1136/ard.57.7.434. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Ryser L., Wright B. D., Aeschlimann A., Mariacher-Gehler S., Stucki G. A new look at the Western Ontario and McMaster Universities Osteoarthritis Index using Rasch analysis. Arthritis Care Res. 1999 Oct;12(5):331–335. doi: 10.1002/1529-0131(199910)12:5<331::aid-art4>3.0.co;2-w. [DOI] [PubMed] [Google Scholar]
  16. Stucki G., Meier D., Stucki S., Michel B. A., Tyndall A. G., Dick W., Theiler R. Evaluation einer deutschen Version des WOMAC (Western Ontario und McMaster Universities) Arthroseindex. Z Rheumatol. 1996 Jan-Feb;55(1):40–49. [PubMed] [Google Scholar]
  17. Söderman P., Malchau H. Validity and reliability of Swedish WOMAC osteoarthritis index: a self-administered disease-specific questionnaire (WOMAC) versus generic instruments (SF-36 and NHP). Acta Orthop Scand. 2000 Feb;71(1):39–46. doi: 10.1080/00016470052943874. [DOI] [PubMed] [Google Scholar]
  18. Thumboo J., Chew L. H., Soh C. H. Validation of the Western Ontario and Mcmaster University osteoarthritis index in Asians with osteoarthritis in Singapore. Osteoarthritis Cartilage. 2001 Jul;9(5):440–446. doi: 10.1053/joca.2000.0410. [DOI] [PubMed] [Google Scholar]
  19. Wigler I., Neumann L., Yaron M. Validation study of a Hebrew version of WOMAC in patients with osteoarthritis of the knee. Clin Rheumatol. 1999;18(5):402–405. doi: 10.1007/s100670050126. [DOI] [PubMed] [Google Scholar]
  20. Wolfe F., Kong S. X. Rasch analysis of the Western Ontario MacMaster questionnaire (WOMAC) in 2205 patients with osteoarthritis, rheumatoid arthritis, and fibromyalgia. Ann Rheum Dis. 1999 Sep;58(9):563–568. doi: 10.1136/ard.58.9.563. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Annals of the Rheumatic Diseases are provided here courtesy of BMJ Publishing Group

RESOURCES