Diabetes-specific or generic measures for health-related quality of life? Evidence from psychometric validation of the D-39 and SF-36

Value Health. May-Jun 2008;11(3):450-61. doi: 10.1111/j.1524-4733.2007.00261.x.

Abstract

Objective: There is a debate regarding the use of disease-specific versus generic instruments for health-related quality of life (HRQOL) measures. We tested the psychometric properties of HRQOL measures using the Diabetes-39 (D-39) and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36).

Methods: This was a cross-sectional study collecting data from 280 patients in Taiwan. Exploratory factor analysis was conducted to evaluate construct validity of the two instruments. Known-groups validity was examined using laboratory indicators (fasting, 2-hour postprandial plasma glucose, and hemoglobin A1c), presence of diabetic complications (retinopathy, nephropathy, neuropathy, diabetic foot disorder, cardiovascular and cerebrovascular disorders), and psychosocial variables (sense of well-being and self-reported diabetes severity). Overall discriminative power of the two instruments was evaluated using the C-statistic.

Results: Three distinct factors were extracted through factor analysis. These factors tapped all subscales of the D-39, fourphysical subscales of the SF-36, and four mental subscales of the SF-36, respectively. Compared with the SF-36, the D-39 demonstrated superior known-groups validity for 2-hour postprandial plasma glucose groups but was inferior for complication groups. Compared with the SF-36, the D-39 discriminated better between self-reported severity known groups, but was inferior between well-being groups. In overall discriminative power, the D-39 discriminated better between laboratory known groups. The SF-36, however, was superior in discriminating between complication known groups.

Conclusions: For psychometric properties, the D-39 and the SF-36 were superior to each other in different regards. The combined use of a disease-specific instrument and a generic instrument may be a useful strategy for diabetes HRQOL assessment.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Attitude to Health
  • Cross-Sectional Studies
  • Diabetes Mellitus / psychology*
  • Factor Analysis, Statistical
  • Female
  • Health Status Indicators*
  • Humans
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care
  • Psychometrics / instrumentation*
  • Quality of Life*
  • ROC Curve
  • Reproducibility of Results
  • Surveys and Questionnaires*
  • Taiwan