Influence of illness perceptions, psychological distress and pain catastrophizing on self-reported symptom severity and functional status in patients with carpal tunnel syndrome

Objective: To examine the influence of illness perceptions, pain catastrophizing and psychological distress on self-reported symptom severity and functional status in patients diagnosed with carpal tunnel syndrome (CTS). Methods: A total of 674 patients with CTS scheduled for surgery at an outpatient treatment center for hand and wrist conditions (September 2017 to August 2018) completed online questionnaires regarding demographic and psychosocial characteristics and self-reported CTS severity. Self-reported severity of CTS was measured with the functional status scale and the symptom severity scale of the Boston Carpal Tunnel Questionnaire. To measure psychosocial factors, the Patient Health Questionnaire-4, Pain Catastrophizing Scale and the Brief Illness Perception Questionnaire were used. Pearson correlation coefficients were calculated to assess univariable relations. Hierarchical linear regression models were used to examine the relation between psychosocial factors and self-reported severity, and the relative contribution of psychosocial factors to self-reported severity, adjusting for patient characteristics and comorbidities. Results: Medium-sized correlations (range 0.32-0.44) with self-reported severity were observed for psychological distress, pain catastrophizing, consequences, identity, concern and emotional representation. Furthermore, these factors (except for concern) were also associated with self-reported severity, when adjusted for baseline characteristics and comorbidities. Hierarchical linear regression models showed that these psychosocial factors explained an additional 20-25% of the variance in self-reported severity of CTS. Conclusion This study shows that psychological distress, pain catastrophizing and illness perceptions play an independent role in self-reported severity of CTS. Clinicians should take these psychosocial factors into account when they are consulted by patients with CTS.