Using the common sense model of illness to examine interrelationships between symptom severity and health outcomes in end-stage osteoarthritis patients.

Objective: The aim was to evaluate the utility of the common sense model (CSM) in characterizing contributors to psychological well-being and quality of life (QoL) in patients with end-stage OA.

Methods: One hundred and twenty patients [34 males, 86 females; mean (s.d.) age 65.52 (9.14) years] with end-stage OA (57.5% hip, 42.5% knee) were recruited. OA symptom severity was evaluated according to the WOMAC; coping styles were assessed with the Carver Brief COPE scale; illness perceptions were explored with the Brief Illness Perceptions Questionnaire; self-efficacy was assessed with the Arthritis Self-efficacy scale; anxiety, depression and overall distress were measured using the Hospital Anxiety and Depression Scale; and QoL was assessed using the WHO Quality of Life-short version. The CSM was used to explore the interrelationships between OA symptom severity, illness perceptions and coping strategies in patients.

Results: Two structural equation models were developed, with both found to have good fit. Consistent with the CSM, the standard model indicated that self-reported OA symptom severity directly influenced illness perceptions, which in turn had direct impacts upon maladaptive coping, distress and QoL. The addition of self-efficacy to the CSM resulted in a complex interaction, with OA severity directly influencing self-efficacy and self-efficacy influencing maladaptive coping, distress and QoL.

Conclusion: We found interrelationships amongst OA activity, illness perceptions, coping strategies, self-efficacy, psychological distress and QoL broadly consistent with the CSM. The CSM may help inform the approach to the psychological support that patients with end-stage OA often require.