The development and validation of a patient-reported quality of life measure for people with mild cognitive impairment

Background: No validated patient-reported outcome measure (PROM) exists specifically to assess quality of life in mild cognitive impairment (MCI); we report a study conducted to develop such a measure. Methods: Semi-structured in-depth interviews were carried out with 23 people with MCI in order to determine items for a draft questionnaire. These interviews were audio-recorded, transcribed, and content analyzed. The draft questionnaire was refined following feedback from a focus group. 280 questionnaires were posted to subjects recruited from memory clinics and research databases, the response rate was 56% i.e. 146 questionnaires were included in the final analysis. The completed questionnaires were analyzed using factor analytic techniques to produce the final measure; construct validity was assessed by correlation with a generic patient-reported outcome measure, the SF-12v2. Results: Factor analysis produced a 13-item measure tapping two domains of patient-reported quality of life ("Emotional Effects" and "Practical Concerns"). Internal consistency reliability was high for both domains (alpha was 0.91 and 0.85 respectively). Both dimensions were highly and significantly correlated with the Mental Component Summary score of the SF-12v2 ("emotional effects" rho = -0.43, p < 0.001 and "practical concerns" rho = -0.56, p < 0.001). Conclusions: The Mild Cognitive Impairment Questionnaire (MCQ) is a 13-item measure developed specifically to measure patient-reported outcomes in people with MCI. It was created on the basis of patient report and has been shown to have good psychometric properties. It is likely to prove valuable in the evaluation of treatment regimes in this patient group.