Asthma Life Impact Scale is ‘reliable and valid’
By Lucy Piper
11 May 2010
Respir Med 2010; 104: 633–643

MedWire News: The newly developed 22-item Asthma Life Impact Scale (ALIS) appears to be a reliable and valid tool for comprehensively assessing the holistic impact of asthma from the patient’s perspective, say researchers.

The new tool fills a gap left by many current patient-reported outcome questionnaires that focus on the symptoms of asthma and a patient’s functional capacity.

“It is intended that the ALIS will be used alongside more traditional measures of symptoms and functional capacity to allow patients to describe the full impact of their condition,” note David Meads, from Galen Research Ltd in Manchester, UK, and colleagues.

The research team generated items for the ALIS during in-depth, unstructured interviews and focus groups with 55 patients with asthma – 39 from the UK and 16 from the USA.

A draft ALIS was developed from the generated data and included items such as: asthma restricts my social activities; asthma affects my close relationships; my illness controls me.

The draft ALIS was then tested during cognitive debriefing interviews with 16 UK and 13 US patients with asthma.

Overall, the patients found the questionnaire was clear and easy to complete. Only a few changes to the draft ALIS were needed, including the addition of an item (my asthma affects my interest in sex) and the removal of three items because they were too severe or were misinterpreted.

In the final validation study, involving 140 UK and 185 US asthma patients who completed the questionnaire on two occasions, approximately 2 weeks apart, the ALIS showed high internal consistency, with a Cronbach’s alpha of 0.94 for UK patients and 0.92 for US patients. Test-retest reliability was also high, at 0.93 and 0.83, respectively.

There was also a moderate-to-high correlation between the ALIS and the existing Asthma Quality of Life Questionnaire (AQLQ).

But the researchers note in the journal Respiratory Medicine that the AQLQ total score explained only 62% and 61% of the UK and US ALIS scores, respectively, “highlighting that they are measuring distinct aspects of the asthma experience.”

The ALIS was also able to discriminate between patients and general health groups and between patients according to the severity of their asthma, although Meads et al stress that more clinical validation of the ALIS data is needed.

They conclude that the ALIS “has high face and content validity,” adding: “Patients contributing to the items… spanned the asthma severity range thus ensuring that the measure will be acceptable to future respondents regardless of how much their lives are impacted by asthma.”

MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

Free abstract

Friendly links


Follow me on Twitter