PURPOSE: While a considerable body of research has explored the relationship between patient expectations and clinical outcomes, few studies investigate the extent to which patient expectations change over time. Further, the temporal relationship between expectations and symptoms is not well researched. METHODS: We conducted a latent class growth analysis on patients (n = 874) with back pain. Patients were categorised in latent profile clusters according to the course of their expectations over 3 months. RESULTS: Nearly 80 % of participants showed a pattern of stable expectation levels, these patients had either high, medium or low levels of expectations for the whole study period. While baseline levels of symptom severity did not discriminate between the three clusters, those in the groups with higher expectations experienced better outcome at 3 months. Approximately 15 % of patients showed decrease in expectation levels over the study period and the remainder were categorised in a group with increasingly positive expectations. In the former clusters, decrease in expectations appeared to be concordant with a plateau in symptom improvement, and in the latter, increase in expectations occurred alongside an increase in symptom improvement rate. CONCLUSIONS: The expectations of most people presenting to primary care with low back pain do not change over the first 3 months of their condition. People with very positive, stable expectations generally experience a good outcome. While we attempted to identify a causal influence of expectations on symptom severity, or vice versa, we were unable to demonstrate either conclusively.
European Spine Journal, 2015, Vol 24, Issue 2, p. 218-226