Clinical & Experimental Allergy

Longitudinal validity and responsiveness of the Food Allergy Quality of Life Questionnaire – Parent Form in children 0–12 years following positive and negative food challenges

Authors

  • A. DunnGalvin,

    1. Department of Paediatrics and Child Health, Clinical Investigation Unit, Cork University Hospital, University College, Cork, Ireland
    Search for more papers by this author
  • C. Cullinane,

    1. Department of Paediatrics and Child Health, Clinical Investigation Unit, Cork University Hospital, University College, Cork, Ireland
    Search for more papers by this author
  • D. A. Daly,

    1. Department of Paediatrics and Child Health, Clinical Investigation Unit, Cork University Hospital, University College, Cork, Ireland
    Search for more papers by this author
  • B. M. J. Flokstra-de Blok,

    1. Department of Paediatrics, Division of Paediatric Pulmonology and Paediatric Allergy, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
    Search for more papers by this author
  • A. E. J. Dubois,

    1. Department of Paediatrics, Division of Paediatric Pulmonology and Paediatric Allergy, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
    Search for more papers by this author
  • J. O'B. Hourihane

    1. Department of Paediatrics and Child Health, Clinical Investigation Unit, Cork University Hospital, University College, Cork, Ireland
    Search for more papers by this author

Correspondence:
Audrey DunnGalvin, Department of Paediatrics and Child Health, Clinical Investigation Unit, Cork University Hospital, University College, Cork, Ireland. E-mail: a.dunngalvin@ucc.ie

Summary

Background There are no published studies of longitudinal health-related quality of life (HRQL) assessments of food-allergic children using a disease-specific measure.

Objective This study assessed the longitudinal measurement properties of the Food Allergy Quality of Life Questionnaire – Parent Form (FAQLQ-PF) in a sample of children undergoing food challenge.

Methods Parents of children 0–12 years completed the FAQLQ-PF and the Food Allergy Independent Measure (FAIM) pre-challenge and at 2 and 6 months post food challenge. In order to evaluate longitudinal validity, differences between Group A (positive challenge) and Group B (negative challenge) were expected over time. We computed correlation coefficients between change scores in the FAQLQ-PF and change scores in the FAIM. To determine the minimally important difference (MID), we used distributional criterion and effect size approaches. A logistic regression model profiled those children falling below this point.

Results Eighty-two children underwent a challenge (42 positive; 40 negative). Domains and total score improved significantly at pos-challenge time-points for both groups (all P<0.05). Sensitivity was demonstrated by significant differences between positive and negative groups at 6 months [F(2, 59)=6.221, P<0.003] and by differing improvement on relevant subscales (P<0.05). MID was 0.45 on a seven-point response scale. Poorer quality of life at baseline increased the odds by over 2.0 of no improvement in HRQL scores 6-month time-point. General maternal health (OR 1.252), number of foods avoided (OR 1.369) and children >9 years (OR 1.173) were also predictors. The model correctly identified 84% of cases below MID.

Conclusion The FAQLQ-PF is sensitive to change, and has excellent longitudinal reliability and validity in a food-allergic patient population. The standard error of measurement value of 0.5 points as a threshold for meaningful change in HRQL questionnaires was confirmed. The FAQLQ-PF may be used to identify problems in children, to assess the effectiveness of clinical trials or interventions, and to guide the development of regulatory policies.

Cite this as: A. DunnGalvin, C. Cullinane, D. A. Daly, B. M. J. Flokstra-de Blok, A. E. J. Dubois and J. O'B. Hourihane, Clinical & Experimental Allergy, 2010 (40) 476–485.

Ancillary