Validation


To accurately assess the quality of life of patients with severe asthma it is necessary to:


Ask the right questions in the right way. To achieve this we carried out two studies.

  • In the first study, we spoke to people with severe asthma using a semi-structured interview technique. Interview questions explored the impact severe asthma had on their lives1. Information from these interviews was used to make a draft questionnaire.
  • In a second study, the draft questionnaire was discussed with severe asthma patients in a series of focus group. Feedback from patients was used to modify the questionnaire including its wording, question structure, timescale and other properties2.
  • Because of this additional qualitative stage, the SAQ is optimised to the content and wording of severe asthma patients.

Assess the statistical properties of the questionnaire. A series of studies have been published on the statistical properties of the SAQ.

  • Construct validity, internal consistency, discriminant validity and test re-test reliability3.

Two larger studies collected data from six severe asthma specialist centres in the UK.

  • Support for a dividing the SAQ’s questions into three subscales (MyLife, MyMind, MyBody)4.
  • Sensitivity to Change and Minimum Clinically Importance Difference (MCID) of the SAQ5.

  1. Hyland ME, Whalley B, Jones RC, Masoli M. A qualitative study of the impact of severe asthma and its treatment showing that treatment burden is neglected in existing asthma assessment scales. Quality of Life Research. 2015;24:631-9. . https://doi.org/10.1007/s11136-014-0801-x.
  2. Hyland ME, Lanario JW, Pooler J, Masoli M, Jones RC. How patient participation was used to develop a questionnaire that is fit for purpose for assessing quality of life in severe asthma. Health and quality of life outcomes. 2018;16(1):24. https://doi.org/10.1186/s12955-018-0851-9.
  3. Hyland ME, Jones RC, Lanario JW, Masoli M. The construction and validation of the severe asthma questionnaire (SAQ). Eur Respir J. 2018; https://doi.org/10.1183/13993003.00618-2018.
  4. Lanario JW, Hyland ME, Menzies-Gow A, Mansur AH, Dodd JW, Fowler SJ, Jones RC, Masoli M. Validation of subscales of the Severe Asthma Questionnaire (SAQ) using exploratory factor analysis (EFA). Health Qual. Life Outcomes. 2020 Dec; https://doi.org/10.1186/s12955-020-01593-9.
  5. Masoli M, Lanario JW, Hyland ME, et al. The Severe Asthma Questionnaire: sensitivity to change and minimal clinically important difference. Eur Respir J 2021; 57: 2100300; https://doi.org/10.1183/13993003.00300-2021.