Journal of Clinical Epidemiology
Volume 56, Issue 1 , Pages 52-60 , January 2003

Comparative responsiveness of generic and specific quality-of-life instruments

  • Samuel Wiebe

      Affiliations

    • Corresponding Author InformationCorresponding author. Tel.: 519- 663-3984; fax: 519-663-3164.
    • Department of Clinical Neurological Sciences and Epidemiology and Biostatistics, University of Western Ontario, University Campus, London Health Sciences Centre, 339 Windermere Road, London, Ontario, Canada N6A 5A5
  • ,
  • Gordon Guyatt

      Affiliations

    • Department of Clinical Epidemiology and Biostatistics, McMaster University, 1200 Main Street West, L8N 3Z5, Hamilton, Ontario, Canada
    • Department of Medicine, McMaster University, 1200 Main Street West, L8N 3Z5, Hamilton, Ontario, Canada
  • ,
  • Bruce Weaver

      Affiliations

    • Department of Clinical Epidemiology and Biostatistics, McMaster University, 1200 Main Street West, L8N 3Z5, Hamilton, Ontario, Canada
  • ,
  • Suzan Matijevic

      Affiliations

    • The London Health Sciences Centre, 339 Windermere Road, London, Ontario, N6A 5A5, Canada
  • ,
  • Casey Sidwell

      Affiliations

    • The London Health Sciences Centre, 339 Windermere Road, London, Ontario, N6A 5A5, Canada

Received 31 May 2001 ,Revised 2 May 2002 ,Accepted 20 August 2002.

References 

  1. Kantz ME, Harris WJ, Levitsky K, Ware JE, Davies AR. Methods for assessing condition-specific and generic functional status outcomes after total knee replacement. Med Care. 1992;30:MS240–MS252
  2. Guyatt GH, Eagle DJ, Sackett B, Willan A, Griffith L, McIlroy W, et al.  Measuring quality of life in the frail elderly. J Clin Epidemiol. 1993;46:1433–1444
  3. Wiebe S, Rose K, Derry PA, McLachlan RS. Outcome assessment in epilepsy (comparative responsiveness of quality of life and psychosocial instruments). Epilepsia. 1997;38:430–438
  4. Buchbinder R, Bombardier C, Yeung M, Tugwell P. Which outcome measures should be used in rheumatoid arthritis clinical trials? Clinical and quality-of-life measures' responsiveness to treatment in a randomized controlled trial. Arthritis Rheum. 1995;38:1568–1580
  5. Murawski MM, Miederhoff PA. On the generalizability of statistical expressions of health related quality of life instrument responsiveness (a data synthesis). Qual Life Res. 1998;7:11–22
  6. Bouchet C, Guillemin F, Briancon S. Nonspecific effects in longitudinal studies (impact on quality of life measures). J Clin Epidemiol. 1996;49:15–20
  7. Ahlmen M, Sullivan M, Bjelle A. Team versus non-team outpatient care in rheumatoid arthritis (a comprehensive outcome evaluation including an overall health measure). Arthritis Rheum. 1988;31:471–479
  8. Applegate WB, Phillips HL, Schnaper H, Shepherd AMM, Schocken D, Luhr JC, et al.  A randomized controlled trial of the effects of three antihypertensive agents on blood pressure control and quality of life in older women. Arch Intern Med. 1991;151:1817–1823
  9. Boline PD, Kassak K, Bronfort G, Nelson C, Anderson AV. Spinal manipulation vs. amitriptyline for the treatment of chronic tension-type headaches (a randomized clinical trial). J Manipulative Physiol Ther. 1995;18:148–154
  10. Bombardier C, Ware J, Russell IJ, Larson M, Chalmers A, Leighton Read J. Auranofin therapy and quality of life in patients with rheumatoid arthritis (results of a multicentre trial). Am J Med. 1986;81(4):565–578
  11. Borson S, Mcdonald GJ, Gayle T, Deffebach M, Lakshminarayan S, VanTuinen C. Improvement in mood, physical symptoms, and function with nortriptyline for depression in patients with chronic obstructive pulmonary disease. Psychosomatics. 1992;33:190–201
  12. Burman P, Broman JE, Hetta J, Wiklund I, Erfurth EM, Hagg E, et al. Quality of life in adults with growth hormone (GH) deficiency (response to treatment with recombinant human GH in a placebo-controlled 21-month trial). J Clin Endocrinol Metab. 1995;80:3585–3590
  13. Chang SW, Fine R, Siegel D, Chesney M, Black D, Hulley SB. The impact of diuretic therapy on reported sexual function. Arch Intern Med. 1991;151:2402–2408
  14. Churchill DN, Bird DR, Taylor DW, Beecroft ML, Gorman J, Wallace JE. Effect on high-flux hemodialysis on quality of life and neuropsychological function in chronic hemodialysis patients. Am J Nephrol. 1992;12:412–418
  15. Coates A, Gebski V, Stat M, Bishop JF, Jeal PN, Woods RL, et al.  Improving the quality of life during chemotherapy for advanced breast cancer (a comparison of intermittent and continuous treatment strategies). N Engl J Med. 1987;317:1490–1495
  16. Coats AJS, Adamopoulos S, Meyer TE, Conway J, Sleight P. Effects of physical training in chronic heart failure. Lancet. 1990;335:63–66
  17. Croog SH, Levine S, Testa MA, Brown B, Bulpitt CJ, Jenkins CD, et al.  The effects of antihypertensive therapy on the quality of life. N Engl J Med. 1986;314:1657–1664
  18. Croog SH, Kong BW, Levine S, Weir MR, Baume RM, Saunders E. The Black Hypertension Quality of Life Multicenter Trial Group. Hypertensive black men and women (quality of life and effects of antihypertensive medications). Arch Intern Med. 1990;150:1733–1741
  19. Fletcher A, McLoone P, Bulpitt C. Quality of life on angina therapy (a randomized controlled trial of transdermal glyceryl trinitrate against placebo). Lancet. 1988;2:4–8
  20. Goldstein RS, Gort EH, Stubbing D, Avendano MA, Guyatt GH. Randomised controlled trial of respiratory rehabilitation. Lancet. 1994;344:1394–1397
  21. Grunfeld E, Mant D, Yudkin P, Adewuyi-Dalton R, Cole D, Stewart J, et al.  Routine follow up of breast cancer in primary care (randomised trial). BMJ. 1996;313:665–669
  22. Hilbrands LB, Hoitsma AJ, Koene RA. The effect of immunosuppressive drugs on quality of life after renal transplantation. Transplantation. 1995;59:1263–1270
  23. Jacoby A, Johnson A, Chadwick D. Psychosocial outcomes of antiepileptic drug discontinuation. The Medical Research Council Antiepileptic Drug Withdrawal Study Group. Epilepsia. 1992;33:1123–1131
  24. Jaeschke R, Guyatt GH, Willan A, Cook D, Harper S, Morris J, et al.  Effect of increasing doses of beta agonists on spirometric parameters, exercise capacity, and quality of life in patients with chronic airflow limitation. Thorax. 1994;49:479–484
  25. Jones BM, Taylor FJ, Wright OM, Harvison A, McBride M, Spratt PM, et al. Quality of life after heart transplantation in patients assigned to double- or triple-drug therapy. J Heart Transplant. 1990;9:392–396
  26. Jones PW, Bosh TK. Quality of life changes in COPD patients treated with salmeterol. Am J Respir Crit Care Med. 1997;155:1283–1289
  27. Keoghane SR, Lawrence KC, Jenkinson CP, Doll HA, Chappel DB, Cranston DW. The Oxford Laser Prostate Trial (sensitivity to change of three measures of outcome). Urology. 1996;47:43–47
  28. Laupacis A, Wong C, Churchill DN. The Canadian Erythropoietin Study Group. The use of generic and specific quality-of-life measures in hemodialysis in patients treated with erythropoietin. Control Clin Trials. 1991;12:168S–179S
  29. Levenstein JH. Quality of life, symptoms and pulmonary function in asthma. A year-long multicentre double-blind trial of nedocromil sodium versus placebo. Fam Pract. 1991;8:402–403
  30. Lonnqvist J, Sintonen H, Syvalahti E, Appelberg B, Koskinen T, Mannikko T, et al.  Antidepressant efficacy and quality of life in depression (a double-blind study with moclobemide and fluoxetine). Acta Psychiatr Scand. 1994;89:363–369
  31. Omvik P, Thaulow E, Herland OB, Eide I, Midha R, Turner RR. Double-blind, parallel, comparative study on quality of life during treatment with amlodipine or enalapril in mild or moderate hypertensive patients (a multicentre study). J Hypertens. 1993;11:103–113
  32. Petajan JH, Gappmaier E, White AT, Spencer MK, Mino L, Hicks RW. Impact of aerobic training on fitness and quality of life in multiple sclerosis. Ann Neurol. 1996;39:432–441
  33. Regensteiner JG, Steiner JF, Hiatt WR. Exercise training improves functional status in patients with peripheral arterial disease. J Vasc Surg. 1996;23:104–115
  34. Regensteiner JG, Meyer TJ, Krupski WC, Cranford LS, Hiatt WR. Hospital vs home-based exercise rehabilitation for patients with peripheral arterial occlusive disease. Angiology. 1997;48:291–300
  35. Ries AL, Kaplan RM, Limberg TM, Prewitt LM. Effects of pulmonary rehabilitation on physiologic and psychosocial outcomes in patients with chronic obstructive pulmonary disease. Ann Intern Med. 1995;122:823–832
  36. Rutten van Molken MP, Custers F, van Doorslaer EK, Jansen CC, Heurman L, Maesen FP, et al.  Comparison of performance of four instruments in evaluating the effects of salmeterol on asthma quality of life. Eur Respir J. 1995;8:888–898
  37. Salek MS, Finlay AY, Luscombe DK, Allen BR, Berth Jones J, Camp RD, et al.  Cyclosporin greatly improves the quality of life of adults with severe atopic dermatitis. A randomized, double-blind, placebo-controlled trial. Br J Dermatol. 1993;129:422–430
  38. Singh NA, Clements KM, Fiatarone MA. A randomized controlled trial of the effect of exercise on sleep. Sleep. 1997;20:95–101
  39. Smith DF, Baker GA, Davies G, Dewey M, Chadwick DW. Outcomes of add-on treatment with lamotrigine in partial epilepsy. Epilepsia. 1993;34(2):312–322
  40. Stenstrom CH, Arge B, Sundbom A. Dynamic training versus relaxation training as home exercise for patients with inflammatory rheumatic diseases. A randomized controlled study. Scand J Rheumatol. 1996;25:28–33
  41. Testa MA, Hollenberg NK, Anderson RB, Williams GH. Assessment of quality of life by patient with spouse during antihypertensive therapy with atenolol and nifedipine gastrointestinal therapeutic system. Am J Hypertens. 1991;4:363–373
  42. Testa MA, Anderson RB, Nackley JF, Hollenberg NK. The Quality-of-Life Hypertension Study Group. Quality of life and antihypertensive therapy in men (a comparison of captopril with enalapril). N Engl J Med. 1993;328:907–913
  43. Tugwell P, Bombardier C, Buchanan WW, Goldsmith C, Grace E, Bennett KJ, et al.  Methotrexate in rheumatoid arthritis. Impact on quality of life assessed by traditional standard-item and individualized patient preference health status questionnaires. Arch Intern Med. 1990;150:59–62
  44. Watson RG, Tham TC, Johnston BT, McDougall NI. Double blind cross-over placebo controlled study of omeprazole in the treatment of patients with reflux symptoms and physiological levels of acid reflux—the “sensitive oesophagus.”. Gut. 1997;40:587–590
  45. Wiklund I, Karlberg J, Mattsson LA. Quality of life of postmenopausal women on a regimen of transdermal estradiol therapy: a double-blind placebo-controlled study. Am J Obstet Gynecol 1993 168(3pt1):824–830.
  46. Worsfold C, Langridge J, Spalding A, Mullee MA. Comparison between primary care physiotherapy education/advice clinics and traditional hospital based physiotherapy treatment (a randomized trial). Br J Gen Pract. 1996;46:165–168
  47. Block G, Liss C, Reines S, Irr J, Nibbelink D. Comparison of immediate-release and controlled release carbidopa/levodopa in Parkinson's disease. A multicenter 5-year study. The CR First Study Group. Eur Neurol. 1997;37:23–27
  48. Coleman EA, Buchner DM, Cress ME, Chan BK, de Lateur BJ. The relationship of joint symptoms with exercise performance in older adults. J Am Geriatr Soc. 1996;44:14–21
  49. Heiligenstein JH, Ware JE, Beusterien KM, Roback PJ, Andrejasich C, Tollefson GD. Acute effects of fluoxetine versus placebo on functional health and well-being in late-life depression. Int Psychogeriatr. 1995;7(Suppl):125–137
  50. Hilding MB, Backbro B, Ryd L. Quality of life after knee arthroplasty. A randomized study of 3 designs in 42 patients, compared after 4 years. Acta Orthop Scand. 1997;68:156–160
  51. Leanderson J, Wredmark T. Treatment of acute ankle sprain. Comparison of a semi-rigid ankle brace and compression bandage in 73 patients. Acta Orthop Scand. 1995;66:529–531
  52. Bousquet J, Duchateau J, Pignat JC, Fayol C, Marquis P, Mariz S, et al.  Improvement of quality of life by treatment with cetirizine in patients with perennial allergic rhinitis as determined by a French version of the SF-36 questionnaire. J Allergy Clin Immunol. 1996;98:309–316
  53. Greenfield S, Kaplan S, Ware JE. Expanding patient involvement in care (effects on patient outcomes). Ann Intern Med. 1985;102:520–528
  54. Greenfield S, Kaplan SH, Ware JE, Yano EM, Frank HJL. Patients' participation in medical care (effects on blood sugar control and quality of life in diabetes). J Gen Intern Med. 1988;3:448–457
  55. Hallbook O, Hass U, Wanstrom A, Sjodahl R. Quality of life measurement after rectal excision for cancer. Comparison between straight and colonic J-pouch anastomosis. Scand J Gastroenterol. 1997;32:490–493
  56. Hurny C, Bernhard J, Coates AS, Castiglione Gertsch M, Peterson HF, Gelber RD, et al.  Impact of adjuvant therapy on quality of life in women with node-positive operable breast cancer. International Breast Cancer Study Group impact of adjuvant therapy on quality of life in women with node-positive operable breast cancer. International Breast Cancer Study Group. Lancet. 1996;347:1279–1284
  57. Jenkinson C, Lawrence K, McWhinnie D, Gordon J. Sensitivity to change of health status measures in a randomized controlled trial (comparison of the COOP charts and the SF-36). Qual Life Res. 1995;4:47–52
  58. Mansson A, Colleen S, Hermeren G, Johnson G. Which patients will benefit from psychosocial intervention after cystectomy for bladder cancer?. Br J Urol. 1997;80:50–57
  59. O'Neill C, Normand C, Cupples M, McKnight A. A comparison of three measures of perceived distress (results from a study of angina patients in general practice in Northern Ireland). J Epidemiol Commun Health. 1996;50:202–206
  60. Okamoto LJ, Noonan M, DeBoisblanc BP, Kellerman DJ. Fluticasone propionate improves quality of life in patients with asthma requiring oral corticosteroids. Ann Allergy Asthma Immunol. 1996;76:455–461
  61. Patterson RB, Pinto B, Marcus B, Colucci A, Braun T, Roberts M. Value of a supervised exercise program for the therapy of arterial claudication. J Vasc Surg. 1997;25:312–318
  62. Pocock SJ, Henderson RA, Seed P, Treasure T, Hampton JR. Quality of life, employment status, and anginal symptoms after coronary angioplasty or bypass surgery. 3-year follow-up in the Randomized Intervention Treatment of Angina (RITA) Trial. Circulation. 1996;94:135–142
  63. Sand PK, Richardson DA, Staskin DR, Swift SE, Appell RA, Whitmore KE, et al. Pelvic floor electrical stimulation in the treatment of genuine stress incontinence (a multicenter, placebo-controlled trial). Am J Obstet Gynecol. 1995;173:72–79
  64. Simon GE, VonKorff M, Heiligenstein JH, Revicki DA, Grothaus L, Katon W, et al. Initial antidepressant choice in primary care. Effectiveness and cost of fluoxetine vs tricyclic antidepressants. JAMA. 1996;275:1897–1902
  65. Sullivan M, Katon W, Russo J, Dobie R, Sakai C. A randomized trial of nortriptyline for severe chronic tinnitus (effects on depression, disability, and tinnitus symptoms). Arch Intern Med. 1993;153:2251–2259
  66. The German and Austrian Xamoterol Study Group . Double-blind placebo-controlled comparison of digoxin and xamoterol in chronic heart failure. Lancet. 1988;March:489–493
  67. Weinberger M, Kirkman MS, Samsa GP, Shortliffe EA, Landsman PB, Cowper PA, et al.  A nurse-coordinated intervention for primary care patients with non-insulin-dependent diabetes mellitus (impact on glycemic control and health-related quality of life). J Gen Intern Med. 1995;10:59–66
  68. Werner RA, Kessler S. Effectiveness of an intensive outpatient rehabilitation program for postacute stroke patients. Am J Phys Med Rehabil. 1996;75:114–120
  69. Williams HJ, Willkens RF, Samuelson CO, Alarcon GS, Guttadauria M, Yarboro C, et al.  Comparison of low-dose oral pulse methotrexate and placebo in the treatment of rheumatoid arthritis (a controlled clinical trial). Arthritis Rheum. 1985;28:721–730
  70. Bakker C, Rutten M, van Santen Hoeufft M, Bolwijn P, van Doorslaer E, Bennett K, et al. Patient utilities in fibromyalgia and the association with other outcome measures. J Rheumatol. 1995;22:1536–1543
  71. Coulehan JL, Schulberg HC, Block MR, Madonia MJ, Rodriguez E. Treating depressed primary care patients improves their physical, mental, and social functioning. Arch Intern Med. 1997;157:1113–1120
  72. Earlam S, Glover C, Davies M, Fordy C, Allen Mersh TG. Effect of regional and systemic fluorinated pyrimidine chemotherapy on quality of life in colorectal liver metastasis patients. J Clin Oncol. 1997;15:2022–2029
  73. Engblom E, Korpilahti K, Hamalainen H, Ronnemaa T, Puukka P. Quality of life and return to work 5 years after coronary artery bypass surgery. Long-term results of cardiac rehabilitation. J Cardpulm Rehabil. 1997;17:29–36
  74. Filipi CJ, Gaston Johansson F, McBride PJ, Murayama K, Gerhardt J, Cornet DA, et al.  An assessment of pain and return to normal activity. Laparoscopic herniorrhaphy vs open tension-free Lichtenstein repair. Surg Endosc. 1996;10:983–986
  75. Fletcher AE, Bulpitt CJ, Chase DM, Collins WCJ, Furberg CD, Goggin TK, et al.  Quality of life with three antihypertensive treatments (cilazapril, atenolol, nifedipine). Hypertension. 1992;19:499–507
  76. Lavin RA, Pappagallo M, Kuhlemeier KV. Cervical pain (a comparison of three pillows). Arch Phys Med Rehabil. 1997;78:193–198
  77. Mahajan P, Okamoto LJ, Schaberg A, Kellerman D, Schoenwetter WF. Impact of fluticasone propionate powder on health-related quality of life in patients with moderate asthma. J Asthma. 1997;34:227–234
  78. Manzetti JD, Hoffman LA, Sereika SM, Sciurba FC, Griffith BP. Exercise, education, and quality of life in lung transplant candidates. J Heart Lung Transplant. 1994;13:297–305
  79. Money SR, Herd JA, Isaacsohn JL, Davidson M, Cutler B, Heckman J, et al. Effect of cilostazol on walking distances in patients with intermittent claudication caused by peripheral vascular disease. J Vasc Surg. 1998;27:267–274
  80. Persson LC, Carlsson CA, Carlsson JY. Long-lasting cervical radicular pain managed with surgery, physiotherapy, or a cervical collar. A prospective, randomized study. Spine. 1997;22:751–758
  81. Rush DR, Stelmach WJ, Young TL, Kirchdoerfer LJ, Scott Lennox J, Holverson HE, et al.  Clinical effectiveness and quality of life with ranitidine vs placebo in gastroesophageal reflux disease patients (a clinical experience network (CEN) study). J Fam Pract. 1995;41:126–136
  82. Small GW, Birkett M, Meyers BS, Koran LM, Bystritsky A, Nemeroff CB. Impact of physical illness on quality of life and antidepressant response in geriatric major depression. Fluoxetine Collaborative Study Group. J Am Geriatr Soc. 1996;44:1220–1225
  83. Tandon PK, Stander H, Schwarz RP. Analysis of quality of life data from a randomized, placebo-controlled heart-failure trial. J Clin Epidemiol. 1989;42(10):955–962
  84. Weir MR, Berger ML, Weeks ML, Liss CL, Santanello NC. Comparison of the effects on quality of life and of the efficacy and tolerability of lovastatin versus pravastatin. The Quality of Life Multicenter Group comparison of the effects on quality of life and of the efficacy and tolerability of lovastatin versus pravastatin. The Quality of Life Multicenter Group. Am J Cardiol. 1996;77:475–479
  85. Whyman MR, Fowkes FG, Kerracher EM, Gillespie IN, Lee AJ, Housley E, et al. Randomised controlled trial of percutaneous transluminal angioplasty for intermittent claudication. Eur J Vasc Endovasc Surg. 1996;12:167–172
  86. Dougherty CM, Dewhurst T, Nichol WP, Spertus J. Comparison of three quality of life instruments in stable angina pectoris (Seattle Angina Questionnaire, Short Form Health Survey (SF- 36), and Quality of Life Index-Cardiac Version III). J Clin Epidemiol. 1998;51:569–575
  87. Ganiats TG, Palinkas LA, Kaplan RM. Communication (comparison of quality of well-being scale and functional status index in patients with atrial fibrillation). Med Care. 1992;30:958–964
  88. Laupacis A, Bourne R, Rorabeck C, Feeny D, Wong C, Tugwell P, et al.  The effect of elective total hip replacement on health-related quality of life. J Bone Joint Surg. 1993;75-A:1619–1626
  89. Wiklund I, Holst J, Karlberg J, Mattsson LA, Samsioe G, Sandin K, et al.  A new methodological approach to the evaluation of quality of life in postmenopausal women. Maturitas. 1992;14:211–224
  90. Alemi F, Stephens RC, Javalghi RG, Dyches H, Butts J, Ghadiri A. A randomized trial of a telecommunications network for pregnant women who use cocaine. Med Care. 1996;34:OS10–OS20
  91. Booth DC, Deupree RH, Hultgren HN, DeMaria AN, Scott SM, Luchi RJ. The Investigators of Veterans Affairs Cooperative Study No.28. Quality of life after bypass surgery for unstable angina (5-year follow-up results of a veterans affairs cooperative study). Circulation. 1991;83:87–95
  92. Trial Participants RITA. Coronary angioplasty versus coronary artery bypass surgery (the Randomised Intervention Treatment of Angina (RITA) trial). Lancet. 1993;341:573–580
  93. Lawrence K, McWhinnie D, Goodwin A, Doll H, Gordon A, Gray A, et al.  Randomised controlled trial of laparoscopic versus open repair of inguinal hernia (early results). BMJ. 1995;311:981–985
  94. Kazis LE, Anderson JJ, Meenan RF. Effect sizes for interpreting changes in health status. Med Care. 1989;27:S178–S189
  95. Liang MH, Fossel AH, Larson MG. Comparisons of five health status instruments for orthopedic evaluation. Med Care. 1990;28:632–642
  96. Guyatt G, Walter S, Norman G. Measuring change over time (assessing the usefulness of evaluative instruments. Measuring change over time: assessing the usefulness of evaluative instruments). J Chronic Dis. 1987;40:171–178
  97. Liang MH, Larson MG, Cullen KE, Schwartz JA. Comparative measurement efficiency and sensitivity of five health status instruments for arthritis research. Arthritis Rheum. 1985;28:542–547
  98. Deyo RA, Centor RM. Assessing the responsiveness of functional scales to clinical change (an analogy to diagnostic test performance). J Chronic Dis. 1986;39:897–906
  99. Stucki G, Liang MH, Fossel AH, Katz JN. Relative responsiveness of condition-specific and generic health status measures in degenerative lumbar spinal stenosis. J Clin Epidemiol. 1995;48:1369–1378
  100. Wright JG, Young NL. A comparison of different indices of responsiveness. J Clin Epidemiol. 1997;50:239–246
  101. Hagen KB, Smedstad LM, Uhlig T, Kvien TK. The responsiveness of health status measures in patients with rheumatoid arthritis (comparison of disease-specific and generic instruments). J Rheumatol. 1999;26:1474–1480
  102. Harper R, Brazier JE, Waterhouse JC, Walters SJ, Jones NM, Howard P. Comparison of outcome measures for patients with chronic obstructive pulmonary disease (COPD) in an outpatient setting. Thorax. 1997;52:879–887

PII: S0895-4356(02)00537-1

Journal of Clinical Epidemiology
Volume 56, Issue 1 , Pages 52-60 , January 2003