Psychometric development of three new condition-specific questionnaires to measure quality of life (Aneurysm-DQoL), symptoms (Aneurysm-SRQ) and treatment satisfaction (Aneurysm-TSQ) of individuals with abdominal aortic aneurysms

Aims: With increasing interest in patient reported outcomes for people with (or following repair of) abdominal aortic aneurysms (AAA), this study reports on the psychometric evaluation of three new condition-specific measures: the Aneurysm-Dependent Quality of Life (Aneurysm-DQoL) questionnaire, the Aneurysm Symptom Rating Questionnaire (Aneurysm-SRQ) and the Aneurysm Treatment Satisfaction Questionnaire (Aneurysm-TSQ).

Method: Two hundred and eighty six participants from five UK NHS Hospital Trusts were invited to complete the new questionnaires. Participants were recruited and completed questionnaires returned by post. Retest questionnaires were administered to 65 participants approximately 4 months after initial completion. Test-retest reliability was assessed using a two-way random effects single measure intraclass correlation coefficient (ICC 2.1, Index range 0-1). Exploratory Factor Analysis (EFA) was employed to examine the structure of the data.

Results: Responses were returned by 197 participants (69%), including 18 women. Useable data were received from 19 participants under preoperative AAA surveillance and 174 who had already undergone aneurysm repair using open (n=70) or endovascular (n=104) surgery. Participants’ mean age was 75 years (SD=8.09, Range; 60-95). EFA of the Aneurysm-DQoL revealed a one-factor structure that included 20 of the total 23 items (α =0.96, ICC=0.77) and explained 55.54% of the variance. EFA of the Aneurysm-SRQ demonstrated a six-factor structure comprising 24 of the total 44 items. The six factors were: Emotional (n=5, α= 0.88, ICC= 0.69); Weight (n=3, α=0.72, ICC=0.47); Lower Limb (n=5, α =0.76, ICC=0.69); Cognitive (n=3, α=0.84, ICC=0.82); Malaise (n=4, α=0.69, ICC=0.60); and Gastrointestinal (n=4, α =0.73, ICC=0.80), explaining 52.62% of the variance. EFA of the Aneurysm-TSQ identified a subscale for pre-operative treatment satisfaction (Items=7, α=0.87) that explained 52.83 percent of the variance in the data and an 11-item scale for post-op patients only (α=0.90, ICC=0.40-0.88) explaining 49.69% of the variance.

Conclusions: The findings from the present study suggest that the Aneurysm-DQoL, Aneurysm-SRQ and Aneurysm-TSQ have clear structure, good internal consistency reliability and strong test-retest reliability. The questionnaires are now ready for use in clinical trials and routine care. Their use will clarify the precise impact of AAA and its treatment, highlight the issues most relevant to AAA pre- and post-repair and facilitate targeted improvements in care.