Summary
Seventeen patients with primary osteoarthritis of the knee were evaluated with respect to the severity and clinical importance of pain, stiffness and physical function during the conduct of a double-blind randomized controlled trial of flurbiprofen SR versus diclofenac sodium SR using the WOMAC Osteoarthritis Index. Mean importance scores were similar for items within the same dimension as well as between items in different dimensions. In general, low levels of correlation were noted between the severity and importance of symptoms. Analysis of individual WOMAC items within a given subscale indicated that, although highly correlated, they differed from one another. Factor analysis further supported the contention that scores from items within a subscale could be summated into subscale scores. These observations are of importance in the weighting and aggregation of items within discrete dimensions and have the potential for reducing sample size requirements for clinical trials in osteoarthritis.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bombardier, C., Tugwell, P., Sinclair, A., Dok, C., Anderson, G., Buchanan, W.W. Preference for endpoint measures in clinical trials: results of structured workshops. J Rheumatol 1982, 9, 5, 798–801.
Spector, T.D. Epidemiological aspects of studying outcome in rheumatoid arthritis. Br J Rheumatol 1988, 27 (Suppl. I), 5–11.
Altman, R.D., Meenan, R.F., Hochberg, M.C., Bole, G.G.Jr., Brandt, K., Cooke, T.D.V., Greenwald, R.A., Howell, D.S., Kaplan, D., Koopman, W.J., Mankin, H., Mikkelsen, W.M., Moskowitz, R., Sokoloff, L. An approach to developing criteria for the clinical diagnosis and classification of osteoarthritis: A status report of the American Rheumatism Association Diagnostic Subcommittee on Osteoarthritis. J Rheumatol 1983, 10, 2, 180–183.
Bellamy, N., Buchanan, W.W. Outcome measurement in osteoarthritis clinical trials: the case for standardisation. Clin Rheumatol 1984, 3, 3, 293–303.
Guidelines for the clinical evaluation of anti-inflammatory and antirheumatic drugs (adults and children). US Department of Health and Human Services, Public Health Service, Food and Drug Administration, April 1988, 12–15.
Guidelines for the clinical investigation of drugs used in rheumatic diseases. World Health Organization Regional Office for Europe, European League Against Rheumatism, 1983, 1–33.
Feinstein, A.R. Scientific decisions for data and hypotheses. In: Clinical Epidemilogy — The Architecture of Clinical Research. Philadelphia, W.B. Saunders Company, 1985, 515–517.
Stewart, A.L., Ware, J.E.Jr., Brook, R.H. Advances in the measurement of functional status: Construction of aggregate indexes. Med Care 1981, XIX(5), 473–488.
Symthe, H.A., Helewa, A., Goldsmith, C.H. “Independent assessor” and “Pooled Index” as techniques for measuring treatment effects in rheumatoid arthritis. J Rheumatol 1977, 4, 2, 144–152.
Gade, H.G. A contribution to the surgical treatment of osteoarthritis of the hip joint: A clinical study. III. Comments on the follow-up examinations and the evaluation of the therapeutic results. Acta Chir Scand (Suppl) 1947, 120, 37–45.
Freeman, M.A.R., Swanson, S.A.V., Todd, R.C. Total replacement of the knee using the Freeman-Swanson knee prothesis. Orthop Related Res 1973, 94, 153–170.
Bellamy, N. Osteoarthritis-An Evaluative Index for Clinical Trials. M. Sc. Thesis, McMaster University, Hamilton, Canada, 1982.
Bellamy, N., Buchanan, W.W. A preliminary evaluation of the dimensionality and clinical importance of pain and disability in osteoarthritis of the hip and knee. Clin Rheumatol 1986, 5, 2, 231–241.
Bellamy, N., Buchanan, W.W., Goldsmith, C.H., Campbell, J., Stitt, L. Validation study of WOMAC: A health status instrument for measuring clinically-important patient-relevant outcomes following total hip or knee arthroplasty in osteoarthritis. J Orthop Rheumatol 1988, 1, 95–108.
Bellamy, N., Buchanan, W.W., Goldsmith, C.H., Campbell, J., Stitt, L.W. Validation study of WOMAC: A health status instrument for measuring clinically important patient relevant outcomes to antirheumatic drug therapy in patients with osteoarthritis of the hip or knee. J Rheumatol 1988, 15, 12, 1833–1840.
Bellamy, N., Goldsmith, C.H., Buchanan, W.W., Campbell, J., Duku, E. Prior score availability: Observations using the WOM-AC Osteoarthritis Index. Br J Rheumatol 1991, 30, 150–151.
Likert, R., A technic for the measurement of arthritis. Arch Psychol 1932, 140, 44–60.
Scott, J., Huskisson, E.C. Graphic representation of pain. Pain, 1976, 2, 175–184.
Kellgren, J.H., Lawrence, J.S. Radiological assessment of osteoarthrosis. Ann Rheum Dis 1957, 16, 494–502.
The Cooperating Clinics Committee of the American Rheumatism Association. A seven-day variability study of 499 patients with peripheral rheumatoid arthritis. Arthritis Rheum 1965, 8, 2, 302–334.
Guyatt, G.H., Berman, L.B., Townsend, M., Taylor, D.W. Should study subjects see their previous responses? J Chron Dis 1985, 38, 12, 1003–1007.
Scott, J., Huskisson, E.C. Accuracy of subjective measurements made with or without previous scores: an important source of error in serial measurement of subjective states. Ann Rheum Dis 1979, 38, 558–559.
Tugwell, P., Bombardier, C., Buchanan, W.W., Goldsmith, C.H., Grace, E., Hanna, B. The MACTAR patient preference disability questionnaire — an individualized functional priority approach for assessing improvement in physical disability in clinical trials in rheumatoid arthritis. J Rheumatol 1987, 14, 3, 446–451.
Colton, T. Inference on Means. Statistics in Medicine, Boston. Little, Brown and Company, 1974, p. 142.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bellamy, N., Wells, G. & Campbell, J. Relationship between severity and clinical importance of symptoms in osteoarthritis. Clin Rheumatol 10, 138–143 (1991). https://doi.org/10.1007/BF02207652
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02207652