~Fatigue defined as being sustained physical tiredness, mental exhaustion, and a lack of energy is a
well-known symptom of many chronic diseases (1;2) and often a crucial aspect in the management of
chronic diseases (3).
It is a common symptom in patients with psoriatic arthritis (PsA) and for patients impacted by fatigue
it is deemed to be one of the most significant symptoms (2;4;5). Moreover, patients with PsA are
characterised by having a decreased quality of life compared to other patient groups and often fatigue
is reported to be the limiting factor in terms of participation in daily activities (6;7).
Though fatigue is considered an important outcome measure for PsA patients this outcome is not yet
embedded completely in clinical practice or in the scientific thinking within this disease-area. Fatigue
is rarely reported by clinicians and studies on patient-reported fatigue outcomes are limited (2;8)
However, the focus on fatigue is increasing. Recent studies describe the association between fatigue in
PsA and pain, female gender, physical disability, medication status, psychological distress,
longstanding sick leave, and loss of work ability (3;5). Furthermore, biological agents are shown to
have a positive impact and beneficial effect on patients suffering from fatigue suggesting a link
between fatigue and inflammatory signalling (9;10). Moreover, fatigue was only recently added in the
GRAPPA-OMERACT’s core set of outcome measures for PsA (2;4)
To our knowledge the association between underlying components of fatigue in relation to PsA has
never been explored on basis of data from large cohort studies. The aim of the study is to describe the
degree of fatigue in patients with PsA in a nationwide study, and to explore important associated
components of fatigue.