CARD-SARC: mixed-method study to develop a disease-specific health-related quality of life tool for cardiac sarcoidosis

Abstract Introduction Sarcoidosis is a rare inflammatory condition caused by the formation of lumps (granulomas) of abnormal tissue in any organ, and can affect physical, functional, mental, social and economic aspects of life. People living with cardiac sarcoidosis (CS) are likely to have worse clinical outcomes and greater impairment on health-related quality of life (HRQoL) than other sarcoidosis manifestations. HRQoL is the main concern for people living with sarcoidosis. However, measuring HRQoL in people with CS is difficult as existing tools focus on other forms of sarcoidosis (for example, lung, eye or skin involvement) or for specific cardiac symptoms (for example, atrial fibrillation, angina or heart failure), but not specifically for CS. Purpose To develop a disease-specific patient-reported outcome measure (CARD-SARC) to assess the impact of CS on HRQoL. Methods A sequential exploratory mixed-method, multicentre observational cohort study using a clinimetric approach was conducted. The McMaster Framework for evaluative instruments involved three steps (item selection, item scaling and item reduction) which were complemented with recommendations from the consensus-based standards for the selection of health measurement instruments (COSMIN). The item-generation process connected data from quantitative (theory, research findings and systematic review) and qualitative components (qualitative semistructured interviews, clinical observations and experts’ opinion). A simultaneous triangulation (QUAN+qual) method was followed to ensure a comprehensive list of preliminary items. The formatting of items was guided by patient and public involvement (PPI) with a 2-weeks recall period. The item reduction strategy was led by PPI and an international multidisciplinary clinical CS-experts. Results 740 potential items were generated by converging all the different sources and techniques. After removal of duplicates and simultaneous triangulation, a preliminary list with 111 items was reviewed by the CS-expert panel with 26 members (including 11 pulmonologists, 7 cardiologists, 5 CS-patients and 3 specialist-nurses). After a consensus meeting, the CARD-SARC included 61 relevant items in six sections for pilot-testing: "functioning", "social, leisure and occupation", "emotional", psychological", "physical" and "healthcare/self-care". Conclusions This study combined a robust methodology with active PPI engagement to develop the first disease-specific HRQoL tool for CS. Each data source was planned independently, however the input from PPI members was critical during the simultaneous triangulation for item-generation. The contributions of CS-experts (members of the PPI group and clinical multidisciplinary experts) enhanced the content validity of the CARD-SARC. The CARD-SARC has the potential to influence clinical management and treatment options, future research and health-economic stakeholders’ decisions for CS.