Development and Psychometric Assessment of Novel Item Banks for Hereditary Retinal Diseases.

SIGNIFICANCE: This study develops psychometrically valid item banks across 10 areas of quality of life (QoL) specific to people with hereditary retinal diseases, which will enable clinicians and researchers to explore the impact of hereditary retinal diseases across all aspects of QoL. PURPOSE: The purpose of this study was to assess the psychometric properties of hereditary retinal disease QoL item banks using Rasch analysis and demonstrate the effectiveness of a computerized adaptive testing (CAT) system in obtaining precise measurement of QoL using only a few items. METHODS: The hereditary retinal disease item banks were answered by 233 participants (median age, 58 years; range, 18 to 94 years; female participants, 59%). The hereditary retinal disease item banks cover 10 QoL domains: activity limitation, mobility, emotional, social, convenience, economic, health concerns, visual symptoms, ocular comfort symptoms, and general symptoms. Rasch analysis assessed the psychometric properties of the 10 item banks and provided item calibrations for the development of CAT. Computerized adaptive testing simulations were performed to calculate the average number of items required to gain precise measurement of each QoL domain. RESULTS: The convenience, economic, visual symptoms, and the social domains formed unidimensional scales. However, the activity limitation and health concerns domains demonstrated multidimensionality and required major modifications to resolve this, which resulted in four new QoL domains, namely, reading, driving, lighting, and concerns about the disease progression. In total, 10 item banks underwent CAT simulation testing, which indicated that 8 to 12 items were required to gain precise measurement of each QoL domain. CONCLUSIONS: We have developed 10 psychometrically valid item banks to measure the QoL domains relevant to people with hereditary retinal diseases. On average, only 5 and 10 items were required to gain measurement at moderate and high precision, respectively.

Illness Perceptions, Psychiatric Manifestations, and Quality of Life in Patients with Inherited Retinal Dystrophies.

PURPOSE: We aimed to assess psychiatric manifestations, health-related quality of life (HRQoL), and associated illness perceptions in patients with inherited retinal dystrophies (IRD). METHODS: In 48 IRD patients, we assessed a wide range of psychological distress symptoms (Symptom Distress Checklist-90-R), depressive symptom severity (PHQ-9), generic HRQoL (WHOQOL-BREF), and Illness Perceptions (B-IPQ). Ninety-six alleged healthy participants matched for age, sex, and education served as healthy controls and 331 patients with rheumatological disorders served as disease controls. RESULTS: IRD patients exhibited elevated symptoms of phobic anxiety (p=0.049) and paranoid ideation (p=0.028) compared to healthy and disease controls and were less satisfied with their general health (p<0.001) compared to disease controls. They shared, however, similar levels on all other aspects of psychiatric manifestations and HRQoL. The majority of patients acknowledged the hereditary and chronic nature of the illness. They also attributed more symptoms to their disease (illness identity) compared to people with rheumatological disorders (p<0.001), and this attribution was associated with paranoid ideation (p<0.05) and phobic anxiety (p<0.001). CONCLUSIONS: Broadening our view of the psychological variables which should be assessed in IRD patients may help to better identify those psychological parameters which impair the patients' well-being and yet may be amenable to treatment. The design of psycho-educational therapies targeting illness representations may have a beneficial effect upon the IRD patients' psychological distress and HRQoL.