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Title: Introducing the Concept of the Minimally Important Difference to Determine a Clinically Relevant Change on Patient-Reported Outcome Measures in Patients with Intermittent Claudication

PurposeThe minimally important difference (MID) represents the smallest change in score on patient-reported outcome measures that is relevant to patients. The aim of this study was to introduce the MID for the Vascular Quality of Life Questionnaire (VascuQol) and the walking impairment questionnaire (WIQ) for patients with intermittent claudication (IC).MethodsIn this multicenter study, we recruited 294 patients with IC between July and October 2012. Patients completed the VascuQol, with scores ranging from 1 to 7 (worst to best), and the WIQ, with scores ranging from 0 to 1 (worst to best) at first visit and after 4 months follow-up. In addition, patients answered an anchor-question rating their health status compared to baseline, as being improved, unchanged, or deteriorated. The MID for improvement and deterioration was calculated by an anchor-based approach, and determined with the upper and lower limits of the 95 % confidence interval of the mean change of the group who had not changed according to the anchor-question.ResultsFor the MID analyses of the VascuQol and WIQ, 163 and 134 patients were included, respectively. The MID values for the VascuQol (mean baseline score 4.25) were 0.87 for improvement and 0.23 for deterioration. For the WIQ (mean baseline score 0.39), wemore » found MID values of 0.11 and −0.03 for improvement and deterioration, respectively.ConclusionIn this study, we calculated the MID for the VascuQol and the WIQ. Applying these MID facilitates better interpretation of treatment outcomes and can help to set treatment goals for individual care.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6]
  1. Academic Medical Center, Departments of Vascular Surgery and Interventional Radiology (Netherlands)
  2. Achmea Insurances, Division of Health Care (Netherlands)
  3. Erasmus Medical Center, Department of Vascular Surgery (Netherlands)
  4. Onze Lieve Vrouwe Gasthuis, Department of Vascular Surgery (Netherlands)
  5. Academic Medical Center, Department of Radiology (Netherlands)
  6. Academic Medical Center, Department of vascular surgery (Netherlands)
Publication Date:
OSTI Identifier:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cardiovascular and Interventional Radiology; Journal Volume: 38; Journal Issue: 5; Other Information: Copyright (c) 2015 Springer Science+Business Media New York and the Cardiovascular and Interventional Radiological Society of Europe (CIRSE); Article Copyright (c) 2015 The Author(s);; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States