Validation of a Brief Questionnaire Measuring Positive Mindset in Patients With Uveitis

John A. Barry, Annie Folkard, William Ayliffe

Abstract


Aim: Illness may impact the positivity of a person’s mindset. However, patients with visual impairment, such as uveitis, may struggle to complete questionnaires. The aim of this study was to validate a brief and simple measure of positive mindset in people with uveitis. Method: This study was a cross-sectional survey of 200 people with uveitis. The Positive Mindset Index (PMI) questionnaire uses six items to measure a patient’s happiness, confidence, sense of being in control, stability, motivation, and optimism. Results: Exploratory factor analysis revealed a well-fitting unidimensional factor structure (KMO = .898), with strong factor loadings (from .616 to .721) and excellent internal reliability (Cronbach’s α = .926). The PMI showed strong concurrent validity with the mental health subscale of the SF-36 (r = .789) and good construct validity relative to the physical health subscale of the SF-36 (r = .468). Excellent test-retest reliability was seen (r = .806). Patients taking 10 mg or more corticosteroid daily had significantly lower PMI scores than those on a lower dose or no dose (t (170) = 2.298, p < .023). Conclusion: The PMI has good face validity and sound psychometric properties. It is a very brief and simple measure, thus user-friendly for patients with visual impairment, as well as researchers and others using the scale.


Keywords


visual impairment; uveitis; Birdshot; quality of life (QoL); patient reported outcome measure (PROM); questionnaire validation