Interpreting the Clinical Importance of Treatment Outcomes in Chronic Pain Clinical Trials: IMMPACT Recommendations

Acquadro, 2003, Incorporating the patient’s perspective into drug development and communication: An ad hoc task force report of the Patient-Reported Outcomes (PRO) Harmonization group Meeting at the Food and Drug Administration, February 16, 2001, Value Health, 6, 522, 10.1046/j.1524-4733.2003.65309.x Altmaier, 1992, The effectiveness of psychological interventions for the rehabilitation of low back pain: A randomized controlled trial evaluation, Pain, 49, 329, 10.1016/0304-3959(92)90240-C Anastasi, 1997 Anderson, 2005, Role of cutpoints: Why grade pain intensity?, Pain, 113, 5, 10.1016/j.pain.2004.10.024 Anderson, 2001, How to assess cancer pain, 579 Atkinson, 1998, A placebo-controlled randomized clinical trial of nortriptyline for chronic low back pain, Pain, 76, 287, 10.1016/S0304-3959(98)00064-5 Beaton, 2000, Understanding the relevance of measured change through studies of responsiveness, Spine, 25, 3192, 10.1097/00007632-200012150-00015 Beaton, 2001, Looking for important change/differences in studies of responsiveness, J Rheumatol, 28, 400 Beck, 1993 Beck, 1961, An inventory for measuring depression, Arch Gen Psychiatry, 4, 561, 10.1001/archpsyc.1961.01710120031004 Beilin, 2003, The numeric rating scale and labor epidural analgesia, Anesth Analg, 96, 1794, 10.1213/01.ANE.0000061581.23351.29 Bellamy, 1988, 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, 15, 1833 Bellamy, 1992, Osteoarthritis antirheumatic drug trials, III: Setting the delta for clinical trials—results of a consensus development (Delphi) exercise, J Rheumatol, 19, 451 Bellamy, 2001, Towards a definition of “difference” in osteoarthritis, J Rheumatol, 28, 427 Bergstrom, 1999, A psychometric evaluation of the Swedish version of the Multidimensional Pain Inventory (MPI-S): A gender differentiation evaluation, Eur J Pain, 3, 261, 10.1016/S1090-3801(99)90053-8 Bernstein, 1995, On the utility of the West Haven-Yale Multidimensional Pain Inventory, Spine, 8, 956, 10.1097/00007632-199504150-00014 Bird, 2001, Clinically significant changes in pain along the visual analog scale, Ann Emerg Med, 38, 639, 10.1067/mem.2001.118012 Bombardier, 2001, Minimal clinically important difference: Low back pain: Outcome measures, J Rheumatol, 28, 431 Cella, 2002, Group vs individual approaches to understanding the clinical significance of differences or changes in quality of life, Mayo Clin Proc, 77, 384, 10.4065/77.4.384 Cella, 2002, What is clinically meaningful change on the Functional Assessment of Cancer Therapy–Lung (FACT-L) Questionnaire?, J Clin Epidemiol, 55, 285, 10.1016/S0895-4356(01)00477-2 Cella, 2002, Meaningful change in cancer-specific quality of life scores: Differences between improvement and worsening, Qual Life Res, 11, 207, 10.1023/A:1015276414526 Cella, 2002, Combining anchor and distribution-based methods to derive minimal clinically important differences on the Functional Assessment of Cancer Therapy (FACT) Anemia and Fatigue Scales, J Pain Symptom Manage, 24, 547, 10.1016/S0885-3924(02)00529-8 Cepeda, 2003, What decline in pain intensity is meaningful to patients with acute pain?, Pain, 105, 151, 10.1016/S0304-3959(03)00176-3 Cleeland Cleeland, 1996, Dimensions of the impact of cancer pain in a four country sample: New information from multidimensional scaling, Pain, 67, 267, 10.1016/0304-3959(96)03131-4 Cleeland, 1994, Pain assessment: Global use of the Brief Pain Inventory, Ann Acad Med, 23, 129 Clinch, 2001, Individualized functional priority approach to the assessment of health related quality of life in rheumatology, J Rheumatol, 28, 445 Cohen, 1988 Crosby, 2003, Defining clinically meaningful change in health-related quality of life, J Clin Epidemiol, 56, 395, 10.1016/S0895-4356(03)00044-1 Crosby, 2004, An integrated method to determine meaningful changes in health-related quality of life, J Clin Epidemiol, 57, 1153, 10.1016/j.jclinepi.2004.04.004 Curran, 1995, Short Form of the Profile of Mood States (POMS-SF): Psychometric information, Psychol Assess, 7, 80, 10.1037/1040-3590.7.1.80 de Vet, 2006, Minimal changes in health status questionnaires: distinction between minimally detectable change and minimally important change, Health Qual Life Outcomes, 4, 54, 10.1186/1477-7525-4-54 Dworkin, 2003, Pregabalin for the treatment of postherpetic neuralgia: A randomized, placebo-controlled trial, Neurology, 60, 1274, 10.1212/01.WNL.0000055433.55136.55 Dworkin, 2005, Core outcome measures for chronic pain clinical trials: IMMPACT recommendations, Pain, 113, 9, 10.1016/j.pain.2004.09.012 Edwards, 2004, Mood swings: Variability in the use of the Profile of Mood States, J Pain Symptom Manage, 28, 534, 10.1016/j.jpainsymman.2004.10.004 Endler, 2003, Coping with chronic pain, Pers Indiv Differences, 34, 323, 10.1016/S0191-8869(02)00048-X Eton, 2004, A combination of distribution- and anchor-based approaches determined minimally important differences (MIDs) for four end points in a breast cancer scale, J Clin Epidemiol, 57, 898, 10.1016/j.jclinepi.2004.01.012 Fairbank, 1980, The Oswestry Low Back Pain Disability Questionnaire, Physiotherapy, 66, 271 Farrar Farrar, 2003, Clinically important changes in acute pain outcome measures: A validation study, J Pain Symptom Manage, 25, 406, 10.1016/S0885-3924(03)00162-3 Farrar, 2006, Use of the cumulative proportion of responders analysis graph to present pain data over a range of cut-off points: Making clinical trial data more understandable, J Pain Symptom Manage, 31, 369, 10.1016/j.jpainsymman.2005.08.018 Farrar, 2000, Defining the clinically important difference in pain outcome measures, Pain, 88, 287, 10.1016/S0304-3959(00)00339-0 Farrar, 2001, Clinical importance of changes in chronic pain intensity measured on an 11-point numerical pain rating scale, Pain, 94, 149, 10.1016/S0304-3959(01)00349-9 Ferrari, 2000, Internal structure and validity of the Multidimensional Pain Inventory, Italian language version, Pain Med, 1, 123, 10.1046/j.1526-4637.2000.00020.x Finnerup, 2005, Algorithm for neuropathic pain treatment: An evidence based proposal, Pain, 118, 289, 10.1016/j.pain.2005.08.013 Fischer, 1999, Capturing the patient’s view of change as a clinical outcome measure, JAMA, 282, 1157, 10.1001/jama.282.12.1157 Flor, 1990, Zur anwendbarkeit des West Haven-Yale Multidimensional Pain Inventory im Deutschen sprachraum, Der Schmerz, 4, 82, 10.1007/BF02527839 Forouzanfar, 2003, What is a meaningful pain reduction in patients with complex regional pain syndrome type 1?, Clin J Pain, 19, 281, 10.1097/00002508-200309000-00001 Frost, 2002, Patient, clinician, and population perspectives on determining the clinical significance of quality of life scores, Mayo Clin Proc, 77, 488, 10.1016/S0025-6196(11)62219-2 Gallagher, 2002, Reliability and validity of a Visual Analog Scale for acute abdominal pain in the ED, Am J Emerg Med, 20, 287, 10.1053/ajem.2002.33778 Gallagher, 2001, Prospective validation of clinically important changes in pain severity measured on a visual analog scale, Ann Emerg Med, 38, 633, 10.1067/mem.2001.118863 Geisser, 1997, Assessing depression among persons with chronic pain using the Center for Epidemiological Studies—Depression Scale and the Beck Depression Inventory: A comparative analysis, Clin J Pain, 13, 163, 10.1097/00002508-199706000-00011 Geurts, 2003, Radiofrequency lesioning of dorsal root ganglia for chronic lumbosacral radicular pain: A randomized, double-blind, controlled trial, Lancet, 361, 21, 10.1016/S0140-6736(03)12115-0 Greco, 2003, Adaptation to chronic pain in systemic lupus erythematosus: Applicability of the Multidimensional Pain Inventory, Pain Med, 4, 39, 10.1046/j.1526-4637.2003.03001.x Guy, 1976 Guyatt, 2000, Making sense of quality-of-life data, Med Care, 38, II-175 Guyatt, 2002, A critical look at transition ratings, J Clin Epidemiol, 55, 900, 10.1016/S0895-4356(02)00435-3 Guyatt, 2002, Methods to explain the clinical significance of health status measures, Mayo Clin Proc, 77, 371, 10.4065/77.4.371 Hägg, 2003, The clinical importance of changes in outcome scores after treatment for chronic low back pain, Eur Spine J, 12, 12, 10.1007/s00586-002-0464-0 Hanley, 2006, Clinically significant changes in pain intensity ratings in persons with spinal cord injury or amputation, Clin J Pain, 22, 25, 10.1097/01.ajp.0000148628.69627.82 Hays, 2000, The concept of clinically meaningful difference in health-related quality-of-life research: How meaningful is it?, Pharmacoeconomics, 18, 419, 10.2165/00019053-200018050-00001 Haythornthwaite Heald, 1997, The shoulder pain and disability index: The construct validity and responsiveness of a region-specific disability measure, Phys Ther, 77, 1079, 10.1093/ptj/77.10.1079 Hoffman, 2007, Meta-analysis of psychological interventions for chronic back pain, Health Psychol, 25, 1, 10.1037/0278-6133.26.1.1 Holdgate, 2003, Comparison of a verbal numeric rating scale with the visual analogue scale for the measurement of acute pain, Emerg Med, 15, 441, 10.1046/j.1442-2026.2003.00499.x Huff, 1954 Huse, 2001, The effect of opioids on phantom limb pain and cortical reorganization, Pain, 90, 47, 10.1016/S0304-3959(00)00385-7 Jacobson, 1999, Methods for defining and determining the clinical significance of treatment effects: Description, application, and alternatives, J Consult Clin Psychol, 67, 300, 10.1037/0022-006X.67.3.300 Jaeschke, 1989, Measurement of health status: Ascertaining the minimal clinically important difference, Control Clin Trials, 10, 407, 10.1016/0197-2456(89)90005-6 Jenkins, 1976, Tofranil in the treatment of low back pain, J Int Med Res, 4, 28 Jensen, 2003, Interpretation of visual analog scale ratings and change scores: A reanalysis of two clinical trials of postoperative pain, J Pain, 4, 407, 10.1016/S1526-5900(03)00716-8 Jensen, 1994, Correlates of improvement in multidisciplinary treatment of chronic pain, J Consult Clin Psychol, 62, 172, 10.1037/0022-006X.62.1.172 Johansson, 2000, Low back pain patients in primary care: Subgroups based on the Multidimensional Pain Inventory, Int J Behav Med, 7, 340, 10.1207/S15327558IJBM0704_05 Johansson, 1998, Effects of a cognitive-behavioral pain-management program, Behav Res Ther, 36, 915, 10.1016/S0005-7967(98)00079-5 Juniper, 1994, Determining a minimal important change in a disease-specific quality of life questionnaire, J Clin Epidemiol, 47, 81, 10.1016/0895-4356(94)90036-1 Kazdin, 1999, The meanings and measurement of clinical significance, J Consult Clin Psychol, 67, 332, 10.1037/0022-006X.67.3.332 Kazis, 1989, Effect sizes for interpreting changes in health status, Med Care, 27, S178, 10.1097/00005650-198903001-00015 Kelly, 1998, Does the clinically significant difference in visual analog scale pain scores vary with gender, age, or cause of pain?, Acad Emerg Med, 5, 1086, 10.1111/j.1553-2712.1998.tb02667.x Kelly, 2001, The minimum clinically significant difference in visual analogue scale pain score does not differ with severity of pain, Emerg Med J, 18, 205, 10.1136/emj.18.3.205 Kerns Kerns, 1985, The West Haven-Yale Multidimensional Pain Inventory (WHYMPI), Pain, 23, 345, 10.1016/0304-3959(85)90004-1 King, 2002, Predictors of success of intervention programs for persons with fibromyalgia, J Rheumatol, 29, 1034 Kosinski, 2000, Determining minimally important changes in generic and disease-specific health-related quality of life questionnaires in clinical trials of rheumatoid arthritis, Arthritis Rheum, 43, 1478, 10.1002/1529-0131(200007)43:7<1478::AID-ANR10>3.0.CO;2-M Kraemer, 2003, Measures of clinical significance, J Am Acad Child Adolesc Psychiatry, 42, 1524, 10.1097/00004583-200312000-00022 Lai, 2003, Can an item response theory–based pain item bank enhance measurement precision?, Clin Ther, 25, D34, 10.1016/S0149-2918(03)80267-9 Lin, 2003, Effect of cancer pain on performance status, mood states, and level of hope among Taiwanese cancer patients, J Pain Symptom Manage, 25, 29, 10.1016/S0885-3924(02)00542-0 Lipscomb, 2002, The outcomes of cancer outcomes research: Focusing on the National Cancer Institute’s quality-of-care initiative, Med Care, 40, III3, 10.1097/00005650-200206001-00002 Lousberg, 1999, Psychometric properties of the Multidimensional Pain Inventory, Dutch Language version (MPI-DLV), Behav Res Ther, 37, 167, 10.1016/S0005-7967(98)00137-5 Lydick, 1993, Interpretation of quality of life changes, Qual Life Res, 2, 221, 10.1007/BF00435226 Man-Son-Hing, 2002, Determination of the clinical importance of study results: A review, J Gen Intern Med, 17, 469, 10.1046/j.1525-1497.2002.11111.x Marhold, 2001, A cognitive-behavioral return-to-work program: Effects on pain patients with a history of long-term versus short-term sick leave, Pain, 91, 155, 10.1016/S0304-3959(00)00431-0 McNair, 1992 McQuay, 1998 Mendoza, 2006, Reliability and validity of a modified Brief Pain Inventory short form in patients with osteoarthritis, Eur J Pain, 10, 353, 10.1016/j.ejpain.2005.06.002 Miller, 1956, The magical number seven, plus or minus two: Some limits on our capacity for processing information, Psychol Rev, 63, 81, 10.1037/h0043158 Montoya, 2005, Abnormal affective modulation of somatosensory brain processing among patients with fibromyalgia, Psychosom Med, 67, 957, 10.1097/01.psy.0000188401.55394.18 Moore, 1998, Size is everything: Large amounts of information are needed to overcome random effects in estimating direction and magnitude of treatment effects, Pain, 78, 209, 10.1016/S0304-3959(98)00140-7 Morley, 1999, Systematic review and meta-analysis of randomized controlled trails of cognitive behavior therapy and behavior therapy for chronic pain in adults, excluding headache, Pain, 80, 1, 10.1016/S0304-3959(98)00255-3 Morley, 2002, A confirmatory factor analysis of the Beck Depression Inventory in chronic pain, Pain, 99, 289, 10.1016/S0304-3959(02)00137-9 Nicholas, 1991, Operant-behavioral and cognitive-behavioral treatment for chronic low back pain, Pain, 48, 339, 10.1016/0304-3959(92)90082-M Norman, 2003, Interpretation of changes in health-related quality of life: The remarkable universality of half a standard deviation, Med Care, 41, 582, 10.1097/01.MLR.0000062554.74615.4C Norman, 1997, Methodological problems in the retrospective computation of responsiveness to change: The lessons of Cronbach, J Clin Epidemiol, 50, 869, 10.1016/S0895-4356(97)00097-8 Nunnally, 1994 Osborne, 2006, The reliability and validity of pain interference measures in persons with multiple sclerosis, J Pain Symptom Manage, 32, 217, 10.1016/j.jpainsymman.2006.03.008 Pincus, 2005, Continuous indices of core data set measures in rheumatoid arthritis clinical trials, Arthritis Rheum, 52, 1031, 10.1002/art.20995 Raichle, 2006, The reliability and validity of pain interference measures in persons with spinal cord injury, J Pain, 7, 179, 10.1016/j.jpain.2005.10.007 Redelmeier, 1997, Interpreting small differences in functional status: The Six Minute Walk test in chronic lung disease patients, Am J Respir Crit Care Med, 155, 1278, 10.1164/ajrccm.155.4.9105067 Redelmeier, 1996, Spirometry and dyspnea in patients with COPD, Chest, 109, 1163, 10.1378/chest.109.5.1163 Redelmeier, 1996, Assessing the minimal important difference in symptoms: A comparison of two techniques, J Clin Epidemiol, 49, 1215, 10.1016/S0895-4356(96)00206-5 Reitsma, 1997, Pain and patienthood, Clin J Pain, 13, 9, 10.1097/00002508-199703000-00004 Revicki, 2006, Responsiveness and minimal important differences for patient reported outcomes, Health Qual Life Outcomes, 4, 70, 10.1186/1477-7525-4-70 Robinson, 2005, Multidimensional success criteria and expectations for treatment of chronic pain: The patient perspective, Pain Med, 6, 336, 10.1111/j.1526-4637.2005.00059.x Roland, 1983, A study of the natural history of back pain, part I: Development of a reliable and sensitive measure of disability in low-back pain, Spine, 8, 141, 10.1097/00007632-198303000-00004 Ross, 1989, Relation of implicit theories to the construction of personal histories, Psychol Rev, 96, 341, 10.1037/0033-295X.96.2.341 Rowbotham, 1998, Gabapentin for the treatment of postherpetic neuralgia: A randomized controlled trial, JAMA, 280, 1837, 10.1001/jama.280.21.1837 Rowbotham, 2003, Oral opioid therapy for chronic peripheral and central neuropathic pain, N Engl J Med, 348, 1223, 10.1056/NEJMoa021420 Rudy, 1987 Ruta, 1994, A new approach to the measurement of quality of life: The Patient Generated Index, Med Care, 32, 1109, 10.1097/00005650-199411000-00004 Ruta, 1999, Patient centered assessment of quality of life for patients with four common conditions, Qual Health Care, 8, 22, 10.1136/qshc.8.1.22 Salaffi, 2004, Minimal clinically important changes in chronic musculoskeletal pain intensity measured on a numerical rating scale, Eur J Pain, 283, 10.1016/j.ejpain.2003.09.004 Sator-Katzenschlager, 2003, Does pain relief improve pain behavior and mood in chronic pain patients?, Anesth Analg, 97, 791, 10.1213/01.ANE.0000078584.03856.D3 Scharff, 1995, Psychosocial and behavioral characteristics in chronic headache patients: Support for a continuum and dual-diagnostic approach, Cephalalgia, 15, 216, 10.1046/j.1468-2982.1995.015003216.x Schwartz, 2002, Measurement of fatigue: Determining minimally important clinical differences, J Clin Epidemiol, 55, 239, 10.1016/S0895-4356(01)00469-3 Serlin, 1995, When is cancer pain mild, moderate or severe?, Pain, 61, 277, 10.1016/0304-3959(94)00178-H Slater, 1997, The clinical significance of behavioral treatment for chronic low back pain: An evaluation of effectiveness, Pain, 71, 257, 10.1016/S0304-3959(97)03374-5 Sloan, 2005, Clinical significance of patient-reported questionnaire data: Another step toward consensus, J Clin Epidemiol, 58, 1217, 10.1016/j.jclinepi.2005.07.009 Sloan, 2003, Practical guidelines for assessing the clinical significance of health-related quality of life changes within clinical trials, Drug Inf J, 37, 23, 10.1177/009286150303700105 Smith, 1993, Effects of present pain level on recall of chronic pain and medication use, Pain, 55, 355, 10.1016/0304-3959(93)90011-D Smith, 1998, The meaning of pain: Cancer patients’ rating and recall of pain intensity and affect, Pain, 78, 123, 10.1016/S0304-3959(98)00122-5 Speca, 2000, A randomized, wait-list controlled clinical trial: The effect of a mindfulness meditation-based stress reduction program on mood and symptoms of stress in cancer outpatients, Psychosom Med, 62, 613, 10.1097/00006842-200009000-00004 Sterner, 2001, Early interdisciplinary rehabilitation programme for whiplash associated disorders, Disabil Rehabil, 23, 422, 10.1080/09638280010008852 Stratford, 1996, Defining the minimal level of detectable change for the Roland Morris questionnaire, Phys Ther, 76, 359, 10.1093/ptj/76.4.359 Stucki, 1996, Interpretation of change scores in ordinal clinical scales and health status measures: The whole may not equal the sum of the parts, J Clin Epidemiol, 49, 711, 10.1016/0895-4356(96)00016-9 Symonds, 2002, The clinical significance of quality-of-life results: Practical considerations for specific audiences, Mayo Clin Proc, 77, 572, 10.4065/77.6.572 ten Klooster, 2006, Patient-perceived satisfactory improvement (PPSI): Interpreting meaningful change in pain from the patient’s perspective, Pain, 121, 151, 10.1016/j.pain.2005.12.021 Testa, 2000, Interpretation of quality-of-life outcomes: issues that affect magnitude and meaning, Med Care, 38, II-166 Thieme, 2003, Operant behavioral treatment of fibromyalgia: A controlled study, Arthritis Care Res, 49, 314, 10.1002/art.11124 Todd, 1996, Clinical significance of reported changes in pain severity, Ann Emerg Med, 27, 485, 10.1016/S0196-0644(96)70238-X Todd, 2001, Patient-oriented outcome measures: The promise of definition, Ann Emerg Med, 38, 672, 10.1067/mem.2001.119746 Tubach, 2006, Feeling good rather than feeling better matters more to patients, Arthritis Rheum, 55, 526, 10.1002/art.22110 Tubach, 2005, Evaluation of clinically relevant states in patient reported outcomes in knee and hip osteoarthritis: The patient acceptable symptom state, Ann Rheum Dis, 64, 34, 10.1136/ard.2004.023028 Turk Turk, 2003, Core outcome domains for chronic pain clinical trials: IMMPACT recommendations, Pain, 106, 337, 10.1016/j.pain.2003.08.001 Turk, 2006, Developing outcome measures for pain clinical trials: IMMPACT recommendations, Pain, 125, 208, 10.1016/j.pain.2006.09.028 Turk, 1996, Pain, disability, and physical functioning in subgroups of fibromyalgia patients, J Rheumatology, 23, 1255 Turk, 1990, Robustness of an empirically derived taxonomy of chronic pain patients, Pain, 43, 27, 10.1016/0304-3959(90)90047-H Turk, 1998, Adaptation to metastatic cancer pain, regional/local cancer pain, and non-cancer pain: Role of psychological and behavioral factors, Pain, 73, 247, 10.1016/S0304-3959(97)00187-5 Turner-Stokes, 2003, Outpatient cognitive-behavioral pain management programs: A randomized comparison of a group-based multidisciplinary versus an individual therapy model, Arch Phys Med Rehabil, 84, 781, 10.1016/S0003-9993(03)00015-7 Van Kleef, 1996, Radiofrequency lesion adjacent to the dorsal root ganglion for cervicobrachial pain: A prospective double blind randomized study, Neurosurgery, 38, 1127 Vlaeyen, 1995, Behavioural rehabilitation of chronic low back pain: Comparison of an operant treatment, an operant-cognitive treatment, and an operant-respondent treatment, Br J Clin Psychol, 34, 95, 10.1111/j.2044-8260.1995.tb01443.x Weiner, 2003, Efficacy of percutaneous electrical nerve stimulation for the treatment of chronic low back pain in older adults, J Am Geriatr Soc, 51, 599, 10.1034/j.1600-0579.2003.00202.x Wells, 2001, Minimal clinically important differences: Review of methods, J Rheumatol, 28, 406 Wells, 2006, Low disease activity state in rheumatoid arthritis: Concepts and derivation of minimal disease activity, Clin Exp Rheumatol, 24, S52 Wells, 1993, Minimum important difference between patients with rheumatoid arthritis: The patient’s perspective, J Rheumatol, 20, 557 Wernicke, 2006, A randomized controlled trial of duloxetine in diabetic peripheral neuropathic pain, Neurology, 67, 1411, 10.1212/01.wnl.0000240225.04000.1a Widar, 1999, Pain in persons with post-polio: The Swedish version of the Multidimensional Pain Inventory (MPI), Scand J Caring Sci, 13, 33 Wolinsky, 1998, Changes in the SF-36 in 12 months in a clinical sample of disadvantaged older adults, Med Care, 36, 1589, 10.1097/00005650-199811000-00008 Wright, 2003, Interpreting health-related quality of life scores: The simple rule of seven may not be so simple, Med Care, 41, 597, 10.1097/00005650-200305000-00006 Wyrwich, 2005, Estimating clinically significant differences in quality of life outcomes, Qual Life Res, 14, 285, 10.1007/s11136-004-0705-2 Wyrwich, 2003, Clinically important changes in health-related quality of life for patients with chronic obstructive pulmonary disease: An expert consensus panel report, J Gen Intern Med, 18, 196, 10.1046/j.1525-1497.2003.20203.x Wyrwich, 1999, Linking clinical relevance and statistical significance in evaluating intra-individual changes in health related quality of life, Med Care, 37, 469, 10.1097/00005650-199905000-00006 Wyrwich, 1999, Further evidence supporting an SEM-based criterion for identifying meaningful intra-individual changes in health-related quality of life, J Clin Epidemiol, 52, 861, 10.1016/S0895-4356(99)00071-2 Wyrwich, 2000, Identifying meaningful intra-individual change standards for health-related quality of life measures, J Eval Clin Pract, 6, 39, 10.1046/j.1365-2753.2000.00238.x Yost, 2005, Minimally important differences were estimated for the Functional Assessment of Cancer Therapy—Colorectal (FACT-C) instrument using a combination of distribution- and anchor-based approaches, J Clin Epidemiol, 58, 1241, 10.1016/j.jclinepi.2005.07.008