A longitudinal cohort study investigating patient characteristics related to expectations and the association between expectations and 3-month outcome.

Kongsted A, et al.
Spine (Phila Pa 1976). 2013 Oct 9. [Epub ahead of print]

Affiliation
1Nordic Institute of Chiropractic and Clinical Biomechanics, part of Clinical Locomotion Network, Odense, Denmark 2 Institute of Sports Science and Clinical Biomechanics, Research Unit of Clinical Biomechanics, part of Clinical Locomotion Network, University of Southern Denmark, Odense, Denmark 3 Institute of Medical Biometry and Medical Informatics, University of Freiburg, Freiburg, Germany.

Abstract
Study Design. A prospective cohort study conducted in general practice (GP) and chiropractic practice (CP).Objectives. To explore which patient characteristics were associated with recovery expectations in low back pain (LBP) patients, whether expectations predicted 3-month outcome, and to what extent expectations were associated with empirical prognostic factors.Summary of Background Data. Patients’ recovery expectations have been associated with prognosis, but it is largely unknown why patients expect what they do, and how expectations relate to other prognostic factors.Methods. 1169 participants completed questionnaires at their first consultation due to LBP and 78% were followed for 3 months. At baseline, recovery expectations were measured on a 0-10 scale. Outcome measures were LBP intensity and Global Perceived Effect (GPE). Associations were tested in regression models, and the predictive capacity of expectations described in terms of adjusted R and area under the ROC curve (AUC). Correlations between predicted expectations and prognosis were quantified by Spearman’s rho.Results. Expectations were associated with known prognostic factors, mainly LBP history, but were only partly explained by measured factors (adj.R 35% (CP)/ 55% (GP)). Expectations had statistically significant associations with both outcomes after adjusting for other baseline factors, but explained only a little of the variance in LBP (adjusted R: 0.11 CP/0.32 GP) and did not add to the explained variance. The prediction of GPE was limited in CP (AUC 0.59), but more substantial in GP (AUC 0.77) patients. Correlations between predicted expectations and predicted outcome were strong.Conclusions. Patients’ recovery expectations were associated mainly with LBP history and were generally, but not consistently, similar to an empirically predicted prognosis. Expectations were significantly associated with outcome, and may, at least for some outcomes, be a relevant proxy for more complex models. Future studies should explore the effect of addressing negative recovery expectations.

PubMed Abstract:  http://www.ncbi.nlm.nih.gov/m/pubmed/24108283/