Development and validation of the Diabetic Foot Ulcer Scale-Short Form (DFS-SF)
- 356 Downloads
Background: The Diabetic Foot Ulcer Scale (DFS) provides comprehensive measurement of the impact of diabetic foot ulcers on patients’ QOL through self-administration of 64 items comprising 15 subscales.
Objective: To develop and evaluate a short form of the DFS (DFS-SF) to reduce patient burden and the number of outcome measures, and to improve sensitivity to change in clinical condition.
Methods: The DFS-SF was created through the analysis of data from a doubleblind, placebo-controlled, randomised trial of the efficacy and safety of becaplermin (recombinant human platelet-derived growth factor BB) in the treatment of chronic, full-thickness, neuropathic, diabetic foot ulcers. Using these data, items demonstrating poor psychometric properties were eliminated. Exploratory factor analyses were then conducted to develop a new, more parsimonious scaling algorithm that optimised the internal consistency of the new subscales. Finally, data from two additional clinical trials were used to assess replicability of the DFS-SF subscale structure.
Results: The DFS-SF contains a total of 29 items comprising six subscales. The results of both confirmatory and exploratory factor analyses provided support for the scaling algorithm. The DFS-SF subscales showed good internal consistency, reliability and construct validity, and demonstrated sensitivity to ulcer healing.
Conclusions: The results of this investigation indicate that the DFS-SF has good psychometric properties and replicability.
KeywordsNegative Emotion Exploratory Factor Analysis Subscale Score Principal Factor Analysis Becaplermin
This study was funded by Johnson & Johnson Pharmaceutical Research & Development, LLC, Raritan, New Jersey, USA.
- 3.Palumbo PJ, Melton LJ. Peripheral vascular disease and diabetes. In: Hams MI, Hammon RE editors. Diabetes in America. NIH Publication No.: 85-1468. Washington, DC: US Government Printing Office, 1985: 1–21Google Scholar
- 9.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, 1993Google Scholar
- 13.Conway K, Pouget C, Finn P, et al. The cultural validation of the Diabetic Foot Ulcer Scale: methods and issues [abstract]. Qual Life Res 1998; 7: 581Google Scholar
- 23.Littell RC, Milliken GA, Stroup WW, Wolfinger RD. SAS® system for mixed models. Cary (NC): SAS Institute Inc., 1996Google Scholar
- 24.Forsyth BH, Lessler JT, Hubbard ML. Cognitive evaluation of the questionnaire. In: Turner C, Lessler JT, Gfroerer JC, editors. Survey measurement of drug use. Publication No.: 92-1929 Washington, DC: US Department of Health and Human Services (DHHS), 1992: 13–52Google Scholar
- 26.Thurstone LL. Multiple factor analysis. Chicago (IL): University of Chicago Press, 1947Google Scholar
- 27.Hatcher L. A step-by-step approach to using the SAS® system for factor analysis and structural equation modeling. Cary (NC): SAS Institute Inc., 1994Google Scholar
- 29.Streiner DL, Norman GR. Health measurement scales: a practical guide to their development and use. 2nd ed. New York: Oxford University Press, 1995Google Scholar
- 30.Jöreskog K, Sörbom D. LISREL® 8: user’s reference guide. Chicago (IL): Scientific Software International, Inc., 1996Google Scholar
- 31.Hoyle RH, Panter AT. Writing about structural equation models. In: Hoyle RH, editor. Structural equation modeling: concepts, issues, and applications. Thousand Oaks (CA): Sage, 1995:158–76Google Scholar
- 32.Schumacker RE, Lomax RG. A beginner’s guide to structural equation modeling. Mahwah (NJ): Erlbaum, 1996Google Scholar
- 33.Gorsuch RL. Factor analysis. 2nd ed. Hillsdale (NJ): Erlbaum, 1983Google Scholar
- 34.Wrigley CS, Neuhaus JO. The matching of two sets of factors. Am Psychol 1955; 10: 418–9Google Scholar