Samenvatting

STUDY DESIGN A prospective cohort study within care as usual. OBJECTIVE 1. To explore the psychometric properties of a baseline disability questionnaire designed to collect patients expectation. 2. To analyse relationships between satisfaction with care and treatment success in patients with CLBP. 3. To determine the chances of being satisfied with the received care in absence of treatment success. SUMMARY OF BACKGROUND DATA There is a lack of evidence on determinants of treatment satisfaction in patients with chronic low back pain (CLBP), specifically the role of patient's expectation of disability reduction after treatment. METHODS Treatment expectation was measured with questions inspired by the Pain Disability Index (PDI) at baseline. Treatment success was considered if disability at the end of therapy was lower than, or equal to pre-treatment expectation. An exploratory factor analysis was performed on the new questionnaire. Binary logistic regression models were used to analyse how much variance of satisfaction with care was explained by treatment success, pain disability at baseline, gender, age, duration of complaints and pain intensity. The Odds Ratio (OR) of being satisfied when treatment was successful was calculated. RESULTS 609 patients were included. The factor structure of the PDI-expectancy (PDI-E) had optimal fit with a one factor structure. There were low correlations between the expected and baseline disability, pain intensity, and duration of pain. Correlation between treatment success and satisfaction with care was low (χ2 = 0.13; p <0.01). Treatment success had a low contribution to satisfaction with care. Of all participating patients, 51.4% were satisfied with care even when treatment was not successful. The OR for being satisfied was 2.42 when treatment was successful compared to when treatment was not successful. CONCLUSION The PDI-E is internally consistent. Pre-treatment expectation contributes uniquely but slightly to satisfaction with care; patients whose treatment was considered successful have 1.38 - 4.24 times higher chance of being satisfied at the end of treatment. Even when treatment was not successful, 51.4% of the patients with CLBP are satisfied with care. LEVEL OF EVIDENCE 2.