Authors: Sophie Cleanthous, Sara Strzok, Birgit Haier, Stefan Cano & Thomas Morel
Abstract
Introduction
Fatigue is frequently experienced in systemic lupus erythematosus (SLE) and is a key outcome in clinical research trials. However, SLE fatigue is complex and poorly understood, and challenging to measure. We aimed to characterise fatigue from the patients’ perspective and develop a conceptual model of fatigue based on qualitative interviews.
Methods
We conducted semi-structured qualitative interviews exploring fatigue in patients with SLE recruited from a social network (n = 29) and a phase 2 clinical study (n = 43). Transcripts were coded thematically, and codes were inductively categorised into a conceptual model.
Results
Fatigue was the most commonly reported symptom in the interviews and generated a wide range of codes. From these, our concept-driven approach revealed three overarching domains of the fatigue experienced in SLE: (i) physical manifestation of physical and bodily symptoms (including physical energy, stamina and impact on movement); (ii) mental and cognitive manifestation (including mental energy, motivation, and cognitive functioning symptoms); and (iii) susceptibility to fatigue or how easily ‘fatigable’ patients are, meaning how easily they become fatigued and how easily their fatigue is alleviated (including the rapid, disproportionate, and/or unpredictable onset of fatigue, non-restorative sleep, and need for more sleep/rest breaks). Within each of these, participants described the severity, variation and impact of fatigue on everyday life. Participants also described how the SLE fatigue experience differed from ‘everyday tiredness’.
Conclusions
The findings of this research indicate that comprehensive measurement of fatigue in SLE will require consideration and quantification of the three domains described in our conceptual model. Future research will explore whether this conceptual model can form the basis of a valid and reliable measurement of fatigue in SLE.
Key Summary Points |
Why carry out this study?Fatigue is one of the most prevalent and debilitating symptoms in systemic lupus erythematosus (SLE), but remains a complex and poorly understood concept, posing both a treatment and measurement challenge. Existing patient-reported outcomes used to measure fatigue in SLE may lack specificity or clarity, and this study is essential to further improve the assessment of fatigue in SLE. This study aimed to characterise fatigue in SLE from the patients’ perspective and to develop a conceptual model of fatigue in SLE with the potential to form the basis of a new patient-reported outcome instrument. |
What was learned from the study?This study revealed three overarching domains of the fatigue experience in SLE: physical, mental and cognitive and susceptibility to fatigue. Based on these findings, a novel conceptual framework for capturing fatigue in SLE has been developed. |