Background Hand osteoarthritis (OA) results in limitations of activities in daily life. Next to joint-specific also psychosocial factors contribute to the outcome. We have shown that patients beliefs about their disease (illness perceptions) negatively influence their long-term functional outcome. The role on the short-term is unknown.
Objectives We investigated the association of illness perceptions with disability and its predictive value on disability after short-term follow-up of one year in patients with hand OA.
Methods Data were used of the ongoing HOSTAS (Hand OSTeoArthritis in Secondary care) study, which includes consecutive patients diagnosed by their treating rheumatologist with primary hand OA.
Illness perceptions were measured at baseline, using the Illness Perception Questionnaire – Revised (IPQ-R). The IPQ-R measures both cognitive and emotional representations of illness. At baseline and after one year follow-up disability was assessed by the Functional Index for Hand OsteoArthritis (FIHOA); scale 0-30. Physical examination of all DIP, PIP, IP, MCP and 1st CMC joints was performed on baseline for number of joints with bony swellings (0-30), pain upon palpation (0-30), deformity (0-22, not MCP 2-5) and limited range of motion (ROM) (0-22). Linear regression analysis was used to associate scores of each IPQ-R dimension to scores in disability, adjusted for age, sex, BMI, number of joints with bony swellings, pain, limited ROM and deformity. Additional adjustment was made for baseline FIHOA score in longitudinal analysis.
Results 258 patients were studied (mean age 61 yrs, 86.4% women, mean BMI 27.4 kg/m2, median number of joints with bony swellings 11 (range 0-24), pain 3 (0-30), limited ROM 6 (0-22) and deformity 5 (0-17)). After one year, the FIHOA was completed by 198 patients. Mean FIHOA score at baseline was 8.9 (SD 5.9), after one year 9.3 (6.3) and mean change was 0.81 (SD 3.7, range -10 to 12).
At baseline, five dimensions of the IPQ-R were associated with disability. These were; more symptoms attributed to OA on the identity section (β 0.62; 95%CI 0.33, 0.91), more perceived consequences (0.47; 0.32, 0.62), less illness coherence (-0.25; -0.42, -0.08), more negative emotions towards OA (0.35; 0.22, 0.47) and beliefs about psychological factors as a cause (0.22; 0.06, 0.38). Disability at one year follow-up was associated with other baseline IPQ-R dimensions. These were; perceived illness chronicity (0.20; 0.04, 0.36), less perceived treatment control (-0.28; -0.47, -0.09) and immunity as causal factor (-0.25; -0.50, -0.01). On the other dimensions of the IPQ-R a trend was seen with more negative illness perceptions being associated with more disability, both at baseline and follow-up.
Conclusions These results show that illness perceptions are associated with disability cross-sectionally and after short-term follow-up. Dimensions of illness perceptions that are of importance differ cross-sectionally from longitudinally. These results may imply that biopsychosocial interventions aiming at changing negative illness perceptions can contribute to better outcome.
Disclosure of Interest None declared