Abstract
INTRODUCTION: Fatigue is highly prevalent and burdensome in systemic lupus erythematosus (SLE). The Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) is a patient-reported questionnaire that measures physical and mental fatigue and consequent impact on daily living. Qualitative evidence of content validity in SLE is limited. This study (GSK Study 209226) assessed the content validity of the FACIT-Fatigue for SLE and explored patients' experiences of SLE-related fatigue using qualitative methods. METHODS: Fatigue-related themes were identified through semi-structured, hybrid cognitive debriefing and concept elicitation interviews and evaluated for concordance with the FACIT-Fatigue. RESULTS: Fatigue was experienced regularly by all participants (N = 15, 86.7% female) and was rated as the most bothersome symptom of SLE by 11/15 participants. All participants reported emotional impacts of fatigue, while 14/15 and 9/15 participants also reported impacts on social life and physical functioning, respectively. Most (12/15) reported that fatigue interfered with their ability to fulfill work- or school-related roles, and activities of daily living were limited in all participants. All (14/14) reported that a meaningful change in their level of fatigue would be the ability to have a more active and normal lifestyle. Concept mapping showed that all 13 FACIT-Fatigue items mapped directly onto concepts spontaneously mentioned by participants. Cognitive debriefing revealed that 13/15 participants found the instructions easy to understand and 11/15 participants endorsed the recall period (7 days) as appropriate. Participants found the FACIT-Fatigue items were clear and relevant. Most participants (11/15) reported that all response options adequately captured their experience of fatigue. CONCLUSIONS: Qualitative evaluation of the content validity of the FACIT-Fatigue supports it as an appropriate measure for assessing the impact of fatigue on daily living of patients with SLE. The tool is easily understood by patients and a valuable resource for measuring a common and debilitating symptom of this condition.