Advertisement

Quality of Life Research

, Volume 7, Issue 2, pp 95–100 | Cite as

How should we evaluate health status? A comparison of three methods in patients presenting with obstructive sleep apnoea

  • S Petersen
  • C Jenkinson
  • J Stradling
Article

Abstract

The purpose of this paper is to compare three approaches to the measurement of patient-reported health status which produce summary scales of health status: the Patient-generated Index (PGI) is a measure of individual quality of life (QoL), the EuroQol is a measure of QoL the results of which are weighted by utility values gained from community surveys and the SF-36 which produces two summary scales of health status (the physical component summary (PCS) and the mental component summary (MCS) scores). A follow-up interview survey of patients with obstructive sleep apnoea (OSA) was conducted. The patients received continuous positive airways pressure therapy (CPAP) between the two administrations of the questionnaires. One hundred patients presenting with OSA and who were suitable for CPAP therapy were asked if they would take part in the study. The results on the PGI, EuroQol EQ-5D utility weighted scores and ‘thermometer’ scores and SF-36 physical and mental summary scores were measured. Eighty-nine respondents provided sufficient data to calculate PGI and EuroQol scores and 86 patients provided sufficient data to calculate SF-36 summary scores. The PGI indicated substantial improvement after CPAP treatment whereas the EuroQol indicated little or no improvement on either utility weighted or thermometer scores. The SF-36 PCS and MCS scores were lower than those of the general population at baseline, but had improved to the normative levels after treatment. The EuroQol provided a substantially different picture of change to either of the ones gained from the SF-36 or PGI. It is suggested that the EuroQol does not contain questions which relate to important aspects of health and well-being and may not accurately reflect the health state of individuals. Consequently, caution must be exercised to assure that an appropriate instrument has been employed when using health outcomes data to assess or prioritize available health care treatments.

Health status apnoea Patient Generated Index SF-36 EuroQol. 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Wright J, Johns R, Watt I, Melville A, Sheldon T. Health effects of obstructive sleep apnoea and the effectiveness of continuous positive airways pressure therapy: a systematic review of the evidence. Br Med J 1997; 314: 851-859.Google Scholar
  2. 2.
    Smith I, Shneerson J. Is the SF-36 sensitive to sleep disruption. A study in subjects with sleep apnoea. J Sleep Res 1995; 4: 183-188.Google Scholar
  3. 3.
    Jenkinson C, Gray A, Doll H, Lawrence K, Layte R. Evaluation of index and profile measures of health status in a randomised controlled trial. Med Care in press.Google Scholar
  4. 4.
    EuroQol Group. EuroQol — a new facility for measurement of health-related quality of life. Health Policy 1990; 16: 199-208.Google Scholar
  5. 5.
    Ruta DA, Garratt AM. Health status to quality of life measurement. In: Jenkinson C, ed. Measuring Health and Medical Outcomes. London: UCL Press, 1994: pp. 138-159.Google Scholar
  6. 6.
    Ware JE, Sherbourne C. The MOS 36 item short-form health survey. 1: Conceptual framework and item selection. Med Care 1992; 30: 473-483.Google Scholar
  7. 7.
    Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep 1991; 14: 540-545.Google Scholar
  8. 8.
    Torrance GW. Measurement of health state utilities for economic appraisal. J Health Econ 1986; 5: 1-3.Google Scholar
  9. 9.
    Dolan P, Gudex C, Kind P, Williams A. A Social Tariff for EuroQol: Results from a UK General Population Survey. York: University of York, Centre for Health Economics, 1995.Google Scholar
  10. 10.
    Dolan P, Gudex C, Kind P, Williams A. The time trade-off method: results from a general population study. Health Econ 1996; 5: 141-154.Google Scholar
  11. 11.
    Ruta DA, Garratt AM, Leng M, Russell IT, MacDonald LM. A new approach to the measurement of quality of life: the Patient Generated Index. Med Care 1994; 32: 1109-1126.Google Scholar
  12. 12.
    Garratt AM, Ruta DA. Taking a patient-centred approach to outcome measurement. In Hutchinson A, McColl E, Christie M, Riccalton C, eds. Health Outcome Measures in Primary Care Amsterdam: Harwood Academic Publishers, 1986: pp. 77-89.Google Scholar
  13. 13.
    Ware JE, Snow KK, Kosinski M, Gandek B. SF-36 Health Survey Manual and Interpretation Guide. Boston, MA: The Health Institute, New England Medical Center.Google Scholar
  14. 14.
    Ware JE, Kosinski M, Bayliss MS, McHorney C, Rogers WH, Raczek A. Comparison of methods for scoring and statistical analysis of SF-36 health profile and summary measures: summary of results from the Medical Outcomes Study. Med Care 1995; 33(Suppl): AS264-AS279.Google Scholar
  15. 15.
    Jenkinson C, Layte R, Wright L, Coulter A. The UK SF-36: An Analysis and Interpetation Manual. Oxford: Health Services Research Unit, University of Oxford, 1996.Google Scholar
  16. 16.
    Jenkinson C, Layte R, Lawrence K. Development and testing of the SF-36 summary scale scores in the United Kingdom: results from a large scale survey and a clinical trial. Med Care 1997; 35: 410-416.Google Scholar
  17. 17.
    Jenkinson C, Coulter A, Wright L. Short form 36 (SF-36) health survey questionnaire: normative data for adults of working age. BMJ 1993; 306: 1437-1440.Google Scholar
  18. 18.
    Kazis L, Anderson JJ, Meenan RF. Effect sizes for interpreting changes in health status. Med Care 1989; 27(Suppl): S179-S189.Google Scholar
  19. 19.
    Cohen J. Statistical Power for the Behavioural Sciences. New York: Academic Press, 1977.Google Scholar
  20. 20.
    Ware J. Standards for validating health measures: definition and content. J Chronic Dis 1987; 40: 473-478.Google Scholar
  21. 21.
    Jenkinson C, Peto V, Coulter A. Measuring change over time: a comparison of results from a global single item of health status and the multi-dimensional SF-36 health status survey questionnaire in patients presenting with menorrhagia. Qual Life Res 1994; 3: 317-321.Google Scholar
  22. 22.
    Williams A. The Role of the EuroQol Instrument in QALY Calculations. York: Centre for Health Economics, University of York, 1995.Google Scholar
  23. 23.
    Carr-Hill R. A second opinion: health related quality of life measurement-Euro style. Health Policy 1992; 20: 321-328.Google Scholar

Copyright information

© Chapman and Hall 1998

Authors and Affiliations

  • S Petersen
    • 1
  • C Jenkinson
    • 2
  • J Stradling
    • 3
  1. 1.Health Services Research Unit, Department of Public HealthUniversity of Oxford, Institute of Health SciencesOxford
  2. 2.Green CollegeOxfordUK
  3. 3.Osler Chest Unit, Churchill HospitalOxfordUK

Personalised recommendations