Acromegaly Quality of Life Questionnaire (ACROQOL) a new health-related quality of life questionnaire for patients with acromegaly: development and psychometric properties

Abstract

Objective: To develop a disease-specific questionnaire suitable to measure health-related quality of life (HRQOL) in acromegaly (ACROQOL).

Design, patients and measurements: For the development of the ACROQOL questionnaire different sources of information were used: First, a literature search was performed to identify relevant papers describing the impact of acromegaly in HRQOL. Second, 10 endocrinologists identified the main domains of impact on HRQOL in patients with acromegaly. Third, 10 in-depth, semistructured interviews were conducted in acromegalic patients to identify domains and items related to the self-perceived impact of acromegaly in patients' life. Qualitative analyses of the information were performed identifying domains and items to be included in the questionnaire. Those items considered ambiguous, complicated to read, double-barrelled, with jargon terms, too long, or negatively worded were excluded. Each remaining item was subsequently rated by the same panel of endocrinologists and experts in HRQOL evaluation, and assessed according to clarity of wording, frequency of occurrence and importance among patients with acromegaly. Analysis of internal consistency of the questionnaire was evaluated with a Cronbach's Alpha. A preliminary questionnaire was administered to 72 patients with acromegaly. Rasch analysis (dichotomous logistic response model) of the answers given by these patients allowed parameter estimates and model data fit indices to be computed and misfitting items deleted. Frequency of occurrence and degree of agreement with the statements were selected as response choices in a 5-point Likert type scale.

Results: The following domains related to HRQOL in acromegaly were identified: physical and psychological functions, social, daily activities, symptoms, cognition, general health perception, sleep, sexual function, pain, energy and body image. An initial set of 204 expressions were identified from the initial transcripts of the patient interviews. After elimination of ambiguous or unclear expressions, 142 items remained drafted in question form. From the quantitative analysis of the item rank position within each of the three areas of clarity, frequency and importance, the 38-item questionnaire was produced, with satisfactory internal consistency (Cronbach's Alpha 0.94). Rasch analysis produced a further reduction to the final 22-item questionnaire (Cronbach's Alpha 0.91) containing two scales that evaluate physical (eight questions) and psychological aspects related to appearance and personal relations (seven items each). The evaluation of the item parameters confirmed the construct validity of the new instrument. The substantial reliability of the questionnaire suggested the sample was well targeted by the questionnaire. The initial Spanish version was translated into English and presented to five English-speaking Australian patients with acromegaly to assess and correct for comprehension, clarity, cultural relevance and suitable wording.

Conclusions: We present the ACROQOL questionnaire, developed and preliminarily validated to specifically assess HRQOL in patients with acromegaly.