Objective: This study modified the Revised Illness Perception Questionnaire (IPQ-R) in patients with persistent atrial fibrillation (AF).
Design: Qualitative interviews and think-aloud techniques informed modification of the IPQ-R to be specific to AF patients. Confirmatory Factor Analysis (CFA) (n = 198) examined the validity of the modified IPQ-R (AF-IPQ-R). Exploratory factor analysis (EFA) examined the new AF-triggers scale. Construct validity examined associations between the AF-IPQ-R, quality of life (QoL) and beliefs about medicines. Test-retest and internal reliability were examined.
Results: Interviews indicated that patients viewed triggers of AF rather than initial causes of illness as more applicable. Patients believed specific behaviours such as rest could control AF. Treatment control beliefs related to pharmacological and procedural treatments. These data were used to modify the IPQ-R subscales and to develop a triggers of AF scale. CFA indicated good model fit. EFA of the triggers scale indicated three factors: emotional; health behaviours; and over-exertion triggers. Expected correlations were found between the AF-IPQ-R, QoL and treatment beliefs, evidencing good construct validity.
Conclusion: The AF-IPQ-R showed sound psychometric properties. It provides more detailed specification than the IPQ-R of beliefs that may help to understand poor QoL in AF patients, and guidance for future interventions in this area.
Keywords: AF-IPQ-R; IPQ-R; factor analysis; illness perceptions; persistent atrial fibrillation; think aloud.