Skip to main content
Log in

A Review of the Progress Towards Developing Health-Related Quality-of-Life Instruments for International Clinical Studies and Outcomes Research

  • Review Article
  • Published:
PharmacoEconomics Aims and scope Submit manuscript

Summary

This article reviews the international adaptation and use of generic health-related quality-of-life (HRQL) measures over the last several years. It focuses, as examples, on the Nottingham Health Profile (NHP), the Sickness Impact Profile (SIP), the Medical Outcomes Study Short-Form 36 Item Health Survey (MOS SF−36), the EuroQoL, Dartmouth Primary Care Cooperative Information Project (COOP) chart system, the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ) and the World Health Organization’s WHOQOL. These instruments exemplify several different models for developing or adapting HRQL measures described in the literature, each model choosing unique approaches to the process of validation for cross-national use.

There has been considerable scientific activity in recent years aimed at advancing the capabilities for international HRQL assessments. Whereas prior adaptation work was focused exclusively on translation issues, recent work has begun to rely on common methodology for translation and validation of key measurement properties across language versions. Although the major HRQL measures reviewed have not yet reached the point at which there is sufficient evidence for measurement equivalence across different language versions, internationally coordinated projects are planned and under way for these instruments to advance and refine this capacity. Preliminary evidence suggests that there are few prominent differences between countries in ranking of health states that are representative of major HRQL dimensions. and in the levels of impact of illnesses on well-being within those dimensions.

Future studies should collect additional psychometric data to more fully quantify measurement equivalence among the various language versions in which each instrument is available. Additionally, more work is required to address cultural differences within nations or language groups.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. Kaplan RM, Bush JW. Health-related quality of life measurement for evaluation research and policy analysis. Health Psychol 1992: 1 (1): 61–80

    Article  Google Scholar 

  2. Bullinger M, Anderson R, Cella D, et al. Developing and evaluating cross-cultural instruments from minimum requirementsto optimal models. Qual Life Res 1993: 2: 451–9

    Article  PubMed  CAS  Google Scholar 

  3. Ware JE, Keller S, Bentler P, et al. Comparison of health status measurement models and the validity of SF−36 in Great Britain. Sweden and the USA. Qual Life Res 1994; 3 (1): 68

    Google Scholar 

  4. Kohlmann T. Aggregation of quality of life date from different countries and interpretation of results. Br J Med Econ 1993: 6C: 35–44

    Google Scholar 

  5. Leplege A, Verdier A. The adaptation of health status measures: methodological aspects of the translation procedure. In: Shumaker S, Berzon R, editors. The international assessmentof health-related quality of life. Oxford: Rapid Communicationsof Oxford Ltd., 1995: 93–102

    Google Scholar 

  6. Hunt SM, Mc Ewen J, Mc Kenna SP. The Nottingham Health Profile User’s Manual. Manchester: Galen Research Consultancy.

  7. Bergner M, Bobbitt RA, Kressel S, et al. The sickness impact profile: conceptual foundation and methodology for the development of a health status measure. Int J Health Serv 1976: 6: 393–415

    Article  PubMed  CAS  Google Scholar 

  8. Ware JE, Sherbourne CD. A 36−item Short-Form Health Survey (SF−36): conceptual framework and item selection. Med Care 1992; 30 (6): 473–83

    Article  PubMed  Google Scholar 

  9. Guyatt GH. The philosophy of health-related quality of life translation. Qual Life Res 1993 Dec; 2 (6): 461–5

    Google Scholar 

  10. The EuroQol Group. EuroQol- a new facility for the measurement of health-related quality of life. Health Policy, 1990; 16: 199–208

    Article  Google Scholar 

  11. Aaronson NK, Cull AM, Kaasa S, et al. The European Organization for Research and Treatment of Cancer (EORTC) modularapproach to quality of life assessment in oncology; anupdate. In: Spilker B, editor. Quality of life and pharrnacoeconomicsin clinical trials. 2nd ed. Philadelphia: Lippencott Raven Publishers 1996: 179–90

    Google Scholar 

  12. Landgraf JM, Nelson EC, Dartmouth COOP Primary Care Network. Summary of the WONCA/CooP international healthassessment field trial. Aust Fam Physician 1992; 21: 255–69

    PubMed  CAS  Google Scholar 

  13. WHOQOL Group. Study protocol for the World Health Organization project to develop a quality of life assessment instrument(WHOQOL). Qual Life Res 1993; 2: 153–9

    Article  Google Scholar 

  14. Jenkinson C. Why are we weighting? A critical examination of the use of item weights in a health status measure. Soc Sci Med 1991: 32 (12): 1413–6

    Article  PubMed  CAS  Google Scholar 

  15. Hunt SM, Mc Kenna SP, Mc Ewen J. A quantitative approach to perceived health. J Epidemiol Community Health 1980; 34: 281–5

    Article  PubMed  CAS  Google Scholar 

  16. Hunt SM, Mc Kenna SP, Mc Ewen J, et al. Subjective health status of patients with peripheral vascular disease. Practitioner 1982; 226: 133–6

    PubMed  CAS  Google Scholar 

  17. Mc Kenna SP, Hunt SM, Mc Ewen J, et al. Changes in perceived health of patients recovering from fractures. Public Health 1984; 98: 97–102

    Article  Google Scholar 

  18. Jenkinson C, Fitzpatrick R, Argyle M. The Nottingham Health Profile: an analysis of its sensitivity in differentiating illness groups. Soc Sci Med 1988; 27 (12): 1411–4

    Article  PubMed  CAS  Google Scholar 

  19. Permanyer-Miralda G, Alonso J, Anto JM, et al. Comparison of perceived health status and conventional functional evaluationin stable patients with coronary heart disease. J Clin Epidemiol 1991; 44 (8): 779–86

    Article  PubMed  CAS  Google Scholar 

  20. Dimenas E, Wiklund I, Dahlof C, et al. Differences in the subjective well-being and symptoms of normotensives, borderline hypertensives and hypertensives. J Hypertens 1989: 7: 885–90

    Article  PubMed  CAS  Google Scholar 

  21. Hunt SM, Mc Ewen J, Mc Kenna SP, et al. Subjective health assessments and the perceived outcome of minor surgery. J Psychosom Res 1984; 28: 105–14

    Article  PubMed  CAS  Google Scholar 

  22. Mays N. Relative costs and cost-effectiveness of extracorporeal shock-wave lithotripsy versus percutaneous nephrolithotomyin the treatment of renal and ureteric stones. Soc Sci Med 1991; 32 (12): 1401–12

    Article  PubMed  CAS  Google Scholar 

  23. Wallender M, Palmer L. A monitoring system for adverse drug experiences in a pharmaceutical company: the integration of pre- and post-marketing data. Drug Inf J 1986; 20: 225–35

    Google Scholar 

  24. Mc Homey CA, Tarlov A. Individual-patient monitoring in clinical practice: are available status surveys adequate? Qual Life Res 1995; 4: 293–308

    Article  Google Scholar 

  25. Hunt SM, Mc Kenna SP, Williams J. Reliability of a population survey tool for measuring perceived health problems: a study of patients with osteoarthrosis. J Epidemiol Community Health 1981; 35: 185–8

    Article  Google Scholar 

  26. Kind P, Carr-Hill R. The Nottingham Health Profile: a useful tool for epidemiologists. Soc Sci Med 1987; 25: 905–10

    Article  PubMed  CAS  Google Scholar 

  27. Leavey R, Wilkin D. A comparison of two survey measures of health status. Soc Sci Med 1988; 27 (3): 269–75

    Article  PubMed  CAS  Google Scholar 

  28. Hunt SM, Alonso J, Bucquet D, et al. Cross-cultural adaptation of health measures. Health Policy 1991; 19: 33–44

    Article  PubMed  CAS  Google Scholar 

  29. European Group for Quality of Life Assessment and Health Measurement. European guide to the Nottingham Health Profile. Surrey: Brookwood Medical Publications. 1993: 64–9

    Google Scholar 

  30. Wiklund I, Romanu B, Hunt S. Self-assessed disability in patients with arthrosis of the hip joint. Int Disabil Stud 1988; 10: 159–63

    Article  PubMed  CAS  Google Scholar 

  31. Wiklund I, Karlberg J. Evaluation of quality of life in clinical trials: selecting quality of life measures. Control Clin Trials 1991: 12 Suppl. 4: 204S–16S

    Article  PubMed  CAS  Google Scholar 

  32. Hunt SM, Wiklund I. Cross-cultural variation in the weighting of health statements: a comparison of English and Swedish valuations. Health Policy 1987; 8: 227–35

    Article  Google Scholar 

  33. Ringsberg KC, Wiklund I, Wilhelmsen L. Education of adult patients at an ‘asthma school’: effects on quality of life, knowledge and need for nursing. Eur Respir J 1990: 3: 33–7

    PubMed  CAS  Google Scholar 

  34. van Schayck CP, Rutten-van Molken MP, van Dooslaer EK, et al. Two-year bronchodilator treatment in patients with mild airflow obstruction. Chest 1992; 102: 1384–91

    Article  PubMed  Google Scholar 

  35. Alonso J, Anto J, Gonzalez M, et al. Measurement of general health status of non-oxygen dependent chronic; obstructive pulmonary disease patients. Med Care 1992; 30 (5 Suppl.): MS125–35

    Google Scholar 

  36. Alonso J, Anto J, Moreno C. Spanish version of the Nottingham Health Profile: translation and preliminary validity. Am JPublic Health 1990; 80: 704–8

    Article  CAS  Google Scholar 

  37. Bucquet D, Condon S, Ritchie K. The French version of the Nottingham Health Profile: a comparison of item weightswith those of the source version. Soc Sci Med 1990: 30 (7): 809–35

    Article  Google Scholar 

  38. Cella DF, Lloyd SR, Wright B. Cross-cutural instrument equating: current research and future directions. In: Spiker B, editor. Quality oflife and pharmocoecnomomics in clinical trials. 2nd edition. Philadelphia: Lippencott-Raven Publishers. 1996: 707–15

    Google Scholar 

  39. Hays RD, Anderson R, Revizki D. Psychometric considerations in evaluating health-related quality oflife measures. Qual Life Res 1993: 2: 441–50

    Article  PubMed  CAS  Google Scholar 

  40. Bergner M, Bobbitt RA, Carter WB, et al. The Sickness Impact Profile: development and final revision of a health status measure. Med Care 1981; 19: 787–805

    Article  PubMed  CAS  Google Scholar 

  41. Rothman M, Hedrick S, Invi T. The Sickness Impact Profile as a measure of the health status of noncognitively impairednursing home residents. Med Care 1989; 27 (3): 5157–67

    Google Scholar 

  42. Finlay AY, Khan GK, Luscombe D, et al. Validation of the Sickness Impact Profile and Psoriasis Disability Index in psoriasis. Br J Dermatol 1990; 123: 751–6

    Article  PubMed  CAS  Google Scholar 

  43. Jones P, Baveystock C, Littlejohns P. Relationships between general health measured with the Sickness Impact Profile andrespiratory symptoms, physiological measures and mood inpatients with chronic airflow limitation. Am Rev Respir Dis 1989; 140: 1538–43

    Article  PubMed  CAS  Google Scholar 

  44. Deyo R, Invi T, Lenninger J, et al. Measuring functional outcomes in chronic disease: a comparison of traditional scalesand a self-administered health status questionnaire in patientswith rheumatoid arthritis. Med Care 1983; 21 (2): 180–92

    Article  PubMed  CAS  Google Scholar 

  45. Pollard WE, Bobbitt RA, Bergner M, et al. The Sickness Impact Profile: reliability of a health status measure. Med Care 1976; 14: 146–55

    Article  PubMed  CAS  Google Scholar 

  46. Sano M, Stem Y, Marder K, et al. A controlled trial of piracetam in intellectually impaired patients with Parkinson’s disease. Mov Disord 1990; 5 (3): 230–4

    Article  PubMed  CAS  Google Scholar 

  47. Rothman M, Hedrick S, Inui T. The Sickness Impact Profile as a measure of health status of noncognitively impaired nursinghome residents. Med Care 1989; 27 Suppl.: S157–67

    Article  Google Scholar 

  48. Liang MH, Fossel AH, Larson MG. Comparisons of five health status instruments for orthopedic evaluation. Med Care 1990; 28: 632–42

    Article  PubMed  CAS  Google Scholar 

  49. Bergner L, Hallstrom A, Bergner M, et al. Health status of survivors of cardiac arrest and of myocardial infarction controls. Am J Public Health 1985; 75 (11): 1321–3

    Article  PubMed  CAS  Google Scholar 

  50. Damiano AM. The Sickness Impact Profile. In: Spilker B, editor. Quality of life and pharmacoeconomics in clinical trials. 2nd ed. Philadelphia: Lippencott-Raven Publishers. 1996: 347–54

    Google Scholar 

  51. Jette AM. Health status indicators: their utility in chronic-disease evaluation research. J Chronic Dis 1980; 33: 567–79

    Article  PubMed  CAS  Google Scholar 

  52. De Bruin AF, De Witte LP, Diederiks JP. Sickness Impact Profile: the state of the art of a generic functional status measure. Soc Sci Med 1992; 8: 1003–14

    Article  Google Scholar 

  53. Patrick DL. Standardization of comparative health status measures: using scales developed in America in an English speaking country. Third Health Survey Research Methods Biennial Conference: 1979 May 16-18; Reston (VA), 216–20 (DHHSpublication no. 80-3268)

    Google Scholar 

  54. Jacobs HM. Health status measurement in family medicine research: the sickness impact profile and its application in a follow-up study in patients with non-specific abdominal complaints. Utrecht: University of Utrecht Press. 1993

    Google Scholar 

  55. Deyo R. Pitfalls in measuring the health status of Mexican Americans: comparative validity of the English and Spanishsickness impact profile. Am J Public Health 1984; 74: 569–73

    Article  PubMed  CAS  Google Scholar 

  56. Hunskaar S, Vinsnes A. The quality of life in women with urinary incontinence as measured by the Sickness Impact Profile. J Am Geriatr Soc 1991: 39: 378–82

    PubMed  CAS  Google Scholar 

  57. Sullivan M, Ahlmen M, Archenholtz B, et al. Measuring health in rheumatic disorders by means of a Swedish Version of the Sickness Impact Profile: results from a population study. Scand J Rheumatol 1990: 17: 439–47

    CAS  Google Scholar 

  58. Ahlmen EM, Bengtsson CB, Sullivan M, et al. A comparison of overall health between patients with rheumatoid arthritis and a population with and without rheumatoid arthritis. Scand J Rheumatol 1990; 19: 413–21

    Article  PubMed  CAS  Google Scholar 

  59. Nydevik I, Hulter-Asberg K. Sickness impact after stroke: a 3−year follow-up. Scand J Prim Care 1992; 10: 284–9

    Article  CAS  Google Scholar 

  60. deBruin AF, Diederiks JPM, deWitte LP, et al. The development of a short generic version of the Sickness Impact Profile. J Clin Epidemiol 1994; 47 (4): 407–18

    Article  PubMed  Google Scholar 

  61. Charlton JR, Patrick DL, Peach H. Use of multi-variate measures of disability in health surveys. J Epidemiol Community Health 1983; 37: 296–304

    Article  PubMed  CAS  Google Scholar 

  62. Sullivan M, Ahlmen M, Bjelle A. Health status assessment in rheumatoid arthritis. 1. Further work on the validity of the Sickness Impact Profile. J Rheumatol 1990; 17: 439–47

    PubMed  CAS  Google Scholar 

  63. Ware J, Snow KK, Kosinski M, et al. SF−36 health survey: manual and interpretation guide. Boston, MA: The Health Institute (New England Medical Center Hospitals). 1993: A1–D1

    Google Scholar 

  64. Stewart A, Hays R, Ware J. The MOS short-form general health survey: reliability and validity in a patient population. Med Care 1988; 26: 724–35

    Article  PubMed  CAS  Google Scholar 

  65. Kantz M, Harris W, Leguitsky K, et al. Methods for assessing condition-specific and generic functional status outcomes after total knee replacement. Med Care 1992; 30: MS240–52

    Article  Google Scholar 

  66. Kurtin PS, Davies AR, Meyer KB, et al. Patient-based health status measurements in outpatient dialysis: early experiences in developing an outcomes assessment program. Med Care 1992; 30 Suppl.: M5136–49

    Google Scholar 

  67. Mc Horney CA, Ware JE Jr, Raczek AE. The MOS 36−item short-form health survey (SF−36). II. Psychometric and clinicaltests of validity in measuring physical and mental healthconstructs. Med Care 1993; 31: 247–63

    Article  Google Scholar 

  68. Mc Homey CA, Ware JE Jr, Lu JF, et al. The MOS 36−Item short form survey (SF−36). III. Tests of data quality, scaling assumptions, and reliability across diverse patient groups. Med Care 1994; 32: 40–66

    Article  Google Scholar 

  69. Aaronson NK, Acquadro C, Alonso J, et al. International quality of life assessment (IQOLA) project. Qual Life Res 1992; 1: 349–51

    Article  PubMed  CAS  Google Scholar 

  70. Ware JE, Gandek B, the IQOLA Project Group. The SF−36 Health Survey: Development and Use in Mental Health Researchand the IQOLA Project. Int J Ment Health 1994; 23: 49–73

    Google Scholar 

  71. Garratt AM, Runa DA, Abdalla MI, et al. The SF−36 health profile: an outcome measure suitable for routine use withinthe NHS? BMJ 1993; 306: 1440–4

    Article  PubMed  CAS  Google Scholar 

  72. Brazier JE, Harper R, Jones NMB, et al. Validating the SF−36 health survey questionnaire: new outcome measure for primary care. BMJ 1992; 305: 160–4

    Article  PubMed  CAS  Google Scholar 

  73. Bullinger M. German translation and psychometric testing of the SF−36 Health Survey: preliminary results from the IQOLA Project. Soc Sci Med 1995; 41 (10): 1359–66

    Article  PubMed  CAS  Google Scholar 

  74. Sullivan M, Karlsson J, Ware JE. The Swedish SF−36 health survey. I. Evaluation of data quality, scaling assumptions, reliability, and construct validity across general populations in Sweden. Soc Sci Med 1995; 41 (10): 1349–55

    Article  PubMed  CAS  Google Scholar 

  75. Thurstone LL, Chave EJ. The measurement of attitude. Chicago: University of Chicago Press, 1928: 1–154

    Google Scholar 

  76. Aaronson NK, Ahmedzai S, Bullinger M, et al. The EORTC core quality-of-life questionnaire: interim results of an internationaltield study. In: Osoba D, editor. Effect of cancer onquality of life. Boca Raton, FL: CRC Press, 1991: 185–203

    Google Scholar 

  77. Aaronson NK, Ahmedzai S, Bergman B, et al. The European Organization for Research and Treatment of Cancer QLQ-C30:a quality-of-life instrument for use in international clinicaltriab in oncology. J Natl Cancer Inst 1993: 85: 365–76

    Article  PubMed  CAS  Google Scholar 

  78. Bjordal K, Kaasa S. Psychometric validation of the EORTC core quality of life questionnaire. 30−item version and a diagnosisspecific module for head and neck cancer patients. Acta Onco1 1992: 31: 311–21

    Article  CAS  Google Scholar 

  79. Bergman B, Sullivan M, Sorenson S. Quality of life during chemotherapy for small cell lung cancer. Acta Oncol 1992: 31 (1): 19–28

    Article  PubMed  CAS  Google Scholar 

  80. Sprangers MAG, Cull A, Bjordal K, et al. The European Organization for Research and Treatment of Cancer approach toquality of life assessment: guidelines for developing questionnaire modules. Qual Life Res 1993; 2: 287–95

    Article  PubMed  CAS  Google Scholar 

  81. Brooks R, Jendteg S, Lindgren B, et al. EuroQol: health related quality of life measurement - results from the Swedish questionnaire exercise. Health Policy 1991; 18: 25–36

    Article  Google Scholar 

  82. Kind P. The EuroQol instrument: an index of health-related quality of life. In: Spilker B, editor. Quality of life andpharmacoeconomics in clinical trials. 2nd ed. Philadelphia: Lippencott-Raven Publishers, 1996: 191–202

    Google Scholar 

  83. Nord E. EuroQol: health related quality of life measurement — valuations of health states by the general public in Norway. Health Policy 1991; 18: 25–36

    Article  PubMed  CAS  Google Scholar 

  84. Brazier J, Jones N, Kind P. Testing the validity ofthe EuroQol and comparing it with the SF-36 health survey questionnaire. Qual Life Res 1993; 2: 169–80

    Article  PubMed  CAS  Google Scholar 

  85. Hollingworth W, Mac Kenzie R, Todd CJ, et al. Measuring changes in quality of life following magnetic resonance imaging of the knee: SF−36. EuroQol, or Rosser Index? QualLife Res 1995: 4: 325–34

    CAS  Google Scholar 

  86. Nelson E, Wasson J, Kirk J, et al. Assessment of function in routine clinical practice: description of the COOP chartmethod and preliminary findings. J Chronic Dis 1987; 40 Suppl.: 55S–63S

    Article  PubMed  Google Scholar 

  87. Nelson EC, Wasson JH, Johnson OJ, et al. Dartmouth COOP functional health assessment charts: brief measures for clinicalpractice. In: Spilker B, editor. Quality of life and pharmacoeconomicsin clinical trials. 2nd ed. Philadelphia: Lippencott-Raven Publishers. 1996: 161–8

    Google Scholar 

  88. Scholten JHG, Van Weel C. Manual for the uSe of the Dartmouth COOP functional health assessment charts/WONCA in measuring functional status in family practice. Part 1. In: Scholten JH, Van Weel C, editors. Functional status assessment in family practice. Lelystad: Meditekst, 1992: 17–50

    Google Scholar 

  89. Scholten JHG, van Weel C. Report of an international workshop of the WONCA Research and Classification Committee. In: Scholten JHG, editor. Functional status assessment in familypractice. Lelystad: Meditekst, 1992: 81–6

    Google Scholar 

  90. Schuling J, Meyboom-de Jong B. Change in clinical status in patients with stroke. In: Scholten JHG, editor. Functional statusassessment in family practice. Lelystad: Meditekst, 1992: 73

    Google Scholar 

  91. Patterson WM. Peak expiratory now rates and functional status in asthma. In: Scholten JHG, editor. Functional status assessmentin family practice. Lelystad: Meditekst, 1992: 74

    Google Scholar 

  92. van Weel C, Matteysen N, Wong Chung D, et al. Change in functional status following an asthma exacerbation. Fam Pract 1991; 8: 404–8

    Article  PubMed  Google Scholar 

  93. Landgraf JM, Nelson EC, Hays RD, et al. Assessing function: does it really make a difference? A preliminary evaluation of the acceptability and utility of the COOP function charts. In: Lipkin Jr M, editor. Functional status measurement in primarycare. New York: Springer-Verlag, 1990: 150–65

    Chapter  Google Scholar 

  94. Coates AK, Wilkin D. Comparing the Nottingham Health Profile with the Dartmouth COOP charts. In: Scholten JHG, editor. Functional status assessment in family practice. Lelystad: Meditekst, 1992: 81–6

    Google Scholar 

  95. Meyboom-de Jong B, Smith RJA. Studies with the Dartmouth COOP charts in general practice: comparison with the Nottinghamhealth protile and the general health questionnaire. In: Lipkin Jr M, editor. Functional status measurement in primarycare. New York: Springer-Verlag, 1990: 132–49

    Chapter  Google Scholar 

  96. Westbury RC. Use of the Dartmouth COOP charts in a Calgary practice. In: Lipkin Jr M, editor. Functional status measurementin primary care. New York: Springer-Verlag, 1990: 166–81

    Chapter  Google Scholar 

  97. Shigemoto H. A trial of the Dartmouth COOP charts in Japan. In: Lipkin Jr M, editor. Functional status measurement in primarycare. New York: Springer-Verlag, 1990: 181–7

    Chapter  Google Scholar 

  98. The WHOQOL Group. The World Health Organization Quality of Life Assessment (WHOQOL): position paper from theWorld Health Organization. Soc Sci Med 1995; 41 (10): 1403–9

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Anderson, R.T., Aaronson, N.K., Bullinger, M. et al. A Review of the Progress Towards Developing Health-Related Quality-of-Life Instruments for International Clinical Studies and Outcomes Research. Pharmacoeconomics 10, 336–355 (1996). https://doi.org/10.2165/00019053-199610040-00004

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.2165/00019053-199610040-00004

Keywords

Navigation