An 18-item standardized Asthma Quality of Life Questionnaire-AQLQ(S)

Abstract

The purpose of the present study was to examine the validity and reliability of the Asthma Quality of Life Questionnaire-AQLQ(S) in a sample of 160 Greek patients with asthma. Following evidence for sample-specific validity, the AQLQ(S) model was examined through exploratory and confirmatory factor analysis. An 18-item AQLQ(S) with the four factors of symptoms, activity limitations, sleep, and exposure in environmental stimuli fits the data (chi(2)/df ratio = 2.26, NNFI = 0.92, CFI = 0.94, SRMR = 0.05). The 18-item AQLQ(S) showed a high internal consistency (Cronbach' a coefficient ranged from 0.83 to 0.96) and high 9-week test-retest reliability (overall r = 0.88, ICC = 0.94). Responsiveness was confirmed throughout 2X2 ANOVA and 2X2 MANOVA, with respect to the total score (F = 42.30, P < 0.05), and the four AQLQ(S) factors (Wilks' lambda = 0.68, F = 17.59, P < 0.05). The cross-sectional correlations between the 18-item AQLQ(S) and the: (1) FEV1% predicted and (2) Borg scale were low and moderately high, respectively. In conclusion, the 18-item AQLQ(S) derived from exploratory and confirmatory factor analysis appeared to have sufficient construct validity, cross-sectional validity, responsiveness, satisfactory test-retest reliability and internal consistency evidence for the Greek sample of adults with asthma.

An 18-item AQLQ(S) model: a reply to Juniper

“…For this purpose, we have used the definitions of the Google dictionary [2]: Modification: (1) the grammatical relation that exists when a word qualifies the meaning of the phrase, (2) is often used instead of adaptation, (3) the act or result of modifying or the condition of being modified; an alteration or adjustment to something, etc. Adaptation: (1) the process of adapting to something, (2) the quality of being adapted; adaptation; adjustment; adjustment to extant conditions, (3) to adjust to new conditions, etc. Translation: (1) translation is the action of interpretation of the meaning of a text, and subsequent production of an equivalent text, also called a translation, that communicates the same message in another language, (2) a written communication in a second language having the same meaning as the written communication in a first language, (3) the act of converting or translating etc.…”

“…Grammatopoulou et al [3] evaluated the reliability and validity of the AQLQ(S) [4] in a Greek sample of patients with asthma. The researchers used the theory of samplespecific reliability and validity, indicating the importance of providing the above indices for each instrument and protocol used in every study.…”

Modification, translation and adaptation of questionnaires should copyright laws be observed?

“…The validation study of the Greek version of our standardised Asthma Quality of Life Questionnaire [AQLQ(S)] [1] by Grammatopoulou et al [2] has raised some important issues concerning health status questionnaires. The challenge for questionnaire developers is to ensure that the instrument really does measure what it says it measures (validity) and that it has strong measurement properties.…”

“…Confidence in the validity, measurement properties and interpretability cannot be obtained from just one 'validation study'. It has to be built up gradually over the years through additional validation studies in different countries (like the one by Grammatopoulou et al [2]) and through good performance in both clinical practice and research.…”

Intellectual property rights and good research practice

“…Yes, we think so, but (and this is an important but) the new instrument cannot be labeled as any of the existing instrument(s) used to derive the new form. Recently, a group of researchers examined the factor structure and psychometric qualities of the standardized version of the Asthma Quality of Life Questionnaire [1] and found that several of the items may not be relevant for the Greek translation of the instrument [2]. While the psychometric results are useful for understanding the measurement qualities of the AQLQ, the authors implied that they developed a new version of the instrument, the AQLQ-18.…”