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An instrument assessing satisfaction with iron chelation therapy: Psychometric testing from an open-label clinical trial

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Abstract

Introduction

The Satisfaction with Iron Chelation Therapy (SICT) instrument was developed based on a literature review, in-depth patient and clinician interviews, and cognitive debriefing interviews. An, open-label, single arm, multicenter trial evaluating the efficacy and safety of deferasirox in patients diagnosed with transfusion-dependent iron overload, provided an opportunity to assess the psychometric measurement properties of the instrument.

Methods

Psychometric analyses were performed using data at baseline from 273 patients with a range of transfusion-dependent iron overload conditions who were participating in a multinational study. Responsiveness was further evaluated for all patients who also had subsequent satisfaction domain scores collected at week 4.

Results

Baseline SICT domain scores had acceptable floor and ceiling effects and internal consistency reliability (Cronbach’s alpha: 0.75–0.85). Item discriminant and item convergent validity were both excellent although one item in each analysis did not meet the specified criterion. Small to moderate correlations were observed between SICT and Short Form 36 Health Survey (SF-36) domain scores. Patients with the highest levels of serum ferritin at baseline (>3100 ng/mL) were the least satisfied about the Perceived Effectiveness of ICT and vice versa. Satisfaction improved in all patients, although there were no clear differences observed between groups of patients defined according to changes in serum ferritin levels from baseline to week 4 (stable, improved, or worsened).

Conclusions

The SICT domains are reliable and valid. Further testing using a more specific criterion (such as assessing patient global ratings of change in satisfaction domains that correspond to the SICT domains) could help to establish with greater confidence the responsiveness of the instrument.

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Authors and Affiliations

  1. Mapi Values, Adelphi Mill, Bollington, Cheshire, SK10 5JB, UK

    Diana Rofail, Adam Gater & Linda Abetz-Webb

  2. Mapi Values, Lyon, 69003, France

    Muriel Viala

  3. Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA

    Jean-Francois Baladi

  4. Policlinico Foundation IRCCS, Università di Milano, Milan, Italy

    Maria Domenica Cappellini

Authors
  1. Diana Rofail
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  2. Muriel Viala
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  3. Adam Gater
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  4. Linda Abetz-Webb
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  5. Jean-Francois Baladi
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  6. Maria Domenica Cappellini
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Correspondence to Diana Rofail.

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Rofail, D., Viala, M., Gater, A. et al. An instrument assessing satisfaction with iron chelation therapy: Psychometric testing from an open-label clinical trial. Adv Therapy 27, 533–546 (2010). https://doi.org/10.1007/s12325-010-0049-y

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  • DOI: https://doi.org/10.1007/s12325-010-0049-y

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