Abstract
Rating scales are increasingly the primary outcome measures in clinical trials. However, clinically meaningful interpretation of such outcomes requires that the scales used satisfy basic requirements (scaling assumptions) within the data. These are rarely tested. The SF-36 is the most widely used patient-reported rating scale. Its scaling assumptions have been challenged in neurological disorders but remain untested in Parkinson's disease (PD). We therefore tested these by analyzing SF-36 data from 202 PD patients (54% men; mean age 70) to determine if it was legitimate to report scores for the eight SF-36 scales and its two summary measures of physical and mental health, and if those scores were reliable and valid. Results supported generation of the eight SF-36 scale scores and their reliabilities were generally good (≥ 0.74 in all but one instance). However, we found limitations that question the meaningfulness of four scales and other limitations that restrict the ability of four scales to detect change in clinical trials (floor/ceiling effects, 19.6–46.2 %). The two SF-36 summary measures were not found to be valid indicators of physical and mental health. This study demonstrates important limitations of the SF-36 and provides the first evidence-based guidelines for its use in PD. The limitations of the SF-36 demonstrated here may explain some unexpected findings in previous studies. However, the main implication is a general one for the clinical research community regarding requirements for reporting rating scale endpoints. Specifically, investigators should routinely provide scale evaluations based on data from within major clinical trials.
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Baron R, Elashaal A, Germon T, Hobart J (2006) Measuring outcomes in cervical spine surgery: think twice before using the SF-36. Spine 31:2575–2584
Bourke SC, Tomlinson M, Williams TL, et al. (2006) Effects of non-invasive ventilation on survival and quality of life in patients with amyotrophic lateral sclerosis: a randomised controlled trial. Lancet Neurol 5:140–147
Byrne BM (2001) Structural equation modeling with AMOS. Basic concepts, applications, and programming. Lawrence Erlbaum Associates, Inc., Mahwah
Cano SJ, Thompson AJ, Bhatia K, et al. (2007) Evidence-based guidelines for using the Short Form 36 in cervical dystonia. Mov Disord 22:122–126
Clancy CM, Eisenberg JM (1998) Outcomes research: measuring the end results of health care. Science 282:245–246
Dallmeijer AJ, Dekker J, Knol DL, et al. (2006) Dimensional structure of the SF-36 in neurological patients. J Clin Epidemiol 59:541–543
Damiano AM, McGrath MM, Willian MK, et al. (2000) Evaluation of a measurement strategy for Parkinson's disease: assessing patient health-related quality of life. Qual Life Res 9:87–100
Defer GL, Widner H, Marié RM, et al. (1999) Core Assessment Program for Surgical Interventional Therapies in Parkinson's Disease (CAPSIT-PD). Mov Disord 14:572–584
Duruöz MT, Poiraudeau S, Fermanian J, Menkes CJ, Amor B, Dougados M, Revel M (1996) Development and validation of a rheumatoid hand functional disability scale that assesses functional handicap. J Rheumatol 23:1167–1172
Fénelon G, Giménez-Roldán S, Montastruc JL, et al. (2003) Efficacy and tolerability of entacapone in patients with Parkinson's disease treated with levodopa plus a dopamine agonist and experiencing wearing-off motor fluctuations. A randomized, double-blind, multicentre study. J Neural Transm 110:239–251
Floyd FJ, Widaman KF (1995) Factor analysis in the development and refinement of clinical assessment instruments. Psychol Assess 7:286–299
Food and Drug Administration (2006) Draft guidance for industry on patient- reported outcome measures: use in medical product development to support labeling claims. Federal Register 71:5862–5863 (Available at: http:// www, fda, gov/cber/gdlns/prolbl, htm)
Fugl-Meyer AR, Melin R, Fugl-Meyer KS (2002) Life satisfaction in 18- to 64- year-old Swedes: in relation to gender, age, partner and immigrant status. J Rehabil Med 34:239–246
Hagell P (2007) Self reported health in people with Parkinson's disease left untreated at diagnosis. J Neurol Neurosurg Psychiatry 78:442
Hobart J (2005) How severe is chronic pain in multiple sclerosis? Nat Clin Pract Neurol 1:80–81
Hobart JC, Freeman JA, Lamping DL (1996) Physician and patient-oriented outcomes in progressive neurological disease: which to measure? Curr Opin Neurol 9:441–444
Hobart J, Freeman J, Lamping D, et al. (2001) The SF-36 in multiple sclerosis: why basic assumptions must be tested. J Neurol Neurosurg Psychiatry 71:363–370
Hobart JC, Williams LS, Moran K, Thompson AJ (2002) Quality of life measurement after stroke: uses and abuses of the SF-36. Stroke 33:1348–1356
Hoehn MM, Yahr M (1967) Parkinsonism: Onset, progression and mortality. Neurology 17:427–442
Hunt SM, McKenna SP, McEwen J, Backett EM, Williams J, Papp E (1980) A quantitative approach to perceived health status: A validation study. J Epidemiol Community Health 34:281–286
Jenkinson C, Hobart J, Chandola T, et al. (2002) Use of the short form health survey (SF-36) in patients with amyotrophic lateral sclerosis: tests of data quality, score reliability, response rates and scaling assumptions. J Neurol 249:178–183
Kosinski M, Keller SD, Hatoum TH, et al. (1999) The SF-36 Health Survey as a generic outcome measure in clinical trials of patients with osteoarthritis and rheumatoid arthritis: Tests of data quality, scaling assumptions and score reliability. Med Care 37(5 Suppl):MS10–MS22
Likert R (1932) A technique for the measurement of attitudes. Arch Psychol 140:1–55
Marshall M, Lockwood A, Bradley C, et al. (2000) Unpublished rating scales: a major source of bias in randomised controlled trials of treatments for schizophrenia. Br J Psychiatry 176:249–252
McDowell I (2006) Measuring health: a guide to rating scales and questionnaires, 3rd ed. Oxford University Press, Inc. , New York
McHorney CA, Tarlov AR (1995) Individual- patient monitoring in clinical practice: are available health status surveys adequate? Qual Life Res 4:293–307
McHorney CA, Ware JE Jr, Lu JFR, Sherbourne CD (1994) The MOS 36- Item Short-Form Health Survey (SF- 36): III. Tests of data quality, scaling assumptions and reliability across diverse patient groups. Med Care 32:40–66
Moher D, Schulz KF, Altman DG, the CONSORT Group (2001) The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomised trials. Lancet 357:1191–1194
Nunnally JC, Bernstein IH (1994) Psychometric theory, 3rd ed. McGraw- Hill, New York
Peto V, Jenkinson C, Fitzpatrick R, Greenhall R (1995) The development and validation of a short measure of functioning and well being for individuals with Parkinson's disease. Qual Life Res 4:241–248
Rubenstein LM, Voelker MD, Chrischilles EA, et al. (1998) The usefulness of the Functional Status Questionnaire and Medical Outcomes Study Short Form in Parkinson's disease research. Qual Life Res 7:279–290
Saris-Baglama RN, Dewey CJ, Chisholm GB, et al. (2004) SF health outcomes™ scoring software user's guide. QualityMetric, Inc. , Lincoln
Scientific Advisory Committee of the Medical Outcomes Trust (2002) Assessing health status and quality-oflife instruments: attributes and review criteria. Qual Life Res 11:193–205
Sullivan M, Karlsson J, Ware JE (1994) Hälsoenkät SF-36. Svensk manual och tolkningsguide (SF-36 Health Survey. Swedish manual and interpretation guide). Sahlgrenska University Hospital, Göteborg, Sweden
Ware JE Jr, Harris WJ, Gandek B, et al. (1997) MAP-R for Windows: multitrait/ multi-item analysis program – revised user's guide. Health Assessment Lab, Boston, MA
Ware JE Jr, Kosinski MA, Keller SD (1994) SF-36 physical and mental health summary scales: a user's manual. Boston: New England Medical Center, The Health Institute
Ware JE Jr, Sherbourne CD (1992) The MOS 36-item short-form health survey (SF-36). I Conceptual framework and item selection. Med Care 30:473–483
Ware JE Jr, Snow KK, Kosinski M, Gandek B (1993) SF-36 Health Survey manual and interpretation guide. Nimrod Press, Boston, MA
Wheatley K, Stowe RL, Clarke CE, et al. (2002) Evaluating drug treatments for Parkinson's disease: how good are the trials? BMJ 324:1508–1511
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Hagell, P., Törnqvist, A.L. & Hobart, J. Testing the SF-36 in Parkinson's disease. J Neurol 255, 246–254 (2008). https://doi.org/10.1007/s00415-008-0708-y
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DOI: https://doi.org/10.1007/s00415-008-0708-y