A multicentre randomized controlled trial of ion-exchange water softeners for the treatment of eczema in children: protocol for the Softened Water Eczema Trial (SWET) (ISRCTN: 71423189)

Authors

  • K.S. Thomas,

    1. Centre of Evidence Based Dermatology, University of Nottingham, King’s Meadow Campus, Nottingham NG7 2NR, U.K.
      *University of East Anglia, Norwich NR4 7TJ, U.K.
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  • T.H. Sach,

    1. Centre of Evidence Based Dermatology, University of Nottingham, King’s Meadow Campus, Nottingham NG7 2NR, U.K.
      *University of East Anglia, Norwich NR4 7TJ, U.K.
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  • and 1 on behalf of the SWET Trial Investigators

    1. Centre of Evidence Based Dermatology, University of Nottingham, King’s Meadow Campus, Nottingham NG7 2NR, U.K.
      *University of East Anglia, Norwich NR4 7TJ, U.K.
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    • 1

      The SWET Trial Investigators are listed in the Appendix.


  • Conflicts of interest
    The authors and members of the trial team have no conflicts of interest to declare. While the study is being conducted with the valuable assistance of the trade associations for the water softener industries, the study team has complete control over the design, analysis and reporting of the study. The views and opinions expressed in this article are those of the authors and do not necessarily reflect those of the National Institute for Health Research Health Technology Assessment Programme.

Kim Thomas.
E-mail: kim.thomas@nottingham.ac.uk

Summary

Background  There is epidemiological evidence linking increased water hardness with increased eczema prevalence. A number of plausible mechanisms can be forwarded to suggest why hard water could exacerbate eczema. The most likely explanation is increased soap usage in hard water areas, the deposits of which can cause skin irritation in individuals with eczema.

Objectives  To assess the cost and cost-effectiveness of ion-exchange water softeners for the treatment of eczema in children.

Patients/Methods  Three hundred and ten children aged 6 months to 16 years, with moderate to severe eczema. The children must live in hard water areas (≥ 200 mg L−1 of calcium carbonate) and have a home that is suitable for the installation of a water softener. This is a single-blind, parallel-group, randomized controlled trial of 12 weeks duration followed by a 4-week cross-over period.

Results/Analysis Plan  Primary outcome: difference in the mean change in disease severity (Six Area, Six Sign Atopic Dermatitis score) at 12 weeks compared with baseline. Secondary outcomes: (i) proportion of time spent moving during the night; (ii) self-reported global changes in eczema severity; (iii) amount of topical treatment used; (iv) Patient Oriented Eczema Measure; (v) number of totally controlled and well controlled weeks; (vi) impact on health-related quality of life for the child (EQ-5D) and the family (Dermatitis Family Impact questionnaire); and (vii) cost-effectiveness. It is planned that recruitment will be completed by the end of 2008 and results will be available towards the end of 2009.

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