Development and validation of the AFSymp™

Abstract

Background
Patients with atrial fibrillation (AF) can be severely incapacitated by symptoms, but validated symptom measures are lacking. The aim of this study was to develop an AF-specific symptom questionnaire (AFSymp™).

Methods
Following a literature review, qualitative interviews with 91 patients (United States [US], n = 30; United Kingdom [UK], n = 16; France, n = 15; Germany, n = 15; Japan, n = 15) with paroxysmal, persistent, and permanent AF were conducted to identify emergent concepts and to develop the items and response options for the AFSymp™. Clinical experts (n = 21) in the US, the UK, France, Germany, and Japan provided feedback on the most clinically relevant symptoms via an email survey. Cognitive interviews with 30 patients were conducted to evaluate content validity. A prospective, observational, psychometric evaluation study (n = 313) consisting of two study visits was performed at 32 sites across the US.

Results
After item reduction, the AFSymp™ consisted of 11 items with a 1-week recall period. Exploratory and confirmatory factor analysis resulted in three subscales (heart symptoms, tiredness, chest discomfort) and two items: dizziness and shortness of breath. Internal consistency was strong across subscales (Cronbach’s ? 0.82–0.91). The test–retest reliability of items and subscales was acceptable (intra-class correlation [ICC] 0.58–0.78). The reproducibility of the single global score was strong (ICC 0.78). The construct and known-groups validity was acceptable.

Conclusion
The AFSymp™ demonstrates evidence of reliability and validity as a comprehensive measure of AF symptoms that can be used to assess patient outcomes in clinical and research settings. More research is needed to evaluate the instrument’s responsiveness.