Contrasting real time quantitative measures (weekly SMS) to patients' retrospective appraisal of their one-year's course of low back pain; a probing mixed-methods study.

Background: Due to the recurrent nature of low back pain (LBP), the traditional concepts of cure and recovery are challenged, and investigating the course rather than status at fixed time-points may help us understand prognosis as well as treatment effect. However, methods of frequent measuring still need development and validation. Therefore, this study aims to evaluate the agreement between continuous, quantitative self-assessment (weekly SMS) of the course of LBP over a one-year period and qualitatively derived retrospective patient self-appraisal of the same time-period. Methods: Participants were 32 subjects with LBP from primary care. The quantitative measures consisted of weekly SMS questions for one-year about pain intensity, days with LBP, and activity limitations for that week. For each subject, the weekly responses were graphed and categorized into categories based on intensity, variation and overall change patterns. Qualitative measures were based on semi-structured telephone interviews one-year after a consultation for LBP, where two coders independently categorized the self-appraisal of LBP course into the same predefined categories as the SMS-based trajectories. Furthermore, patients' perceived overall recovery was related to variation patterns from SMS track. Results: There was perfect agreement for 48% in the pain intensity domain, 53% in the variation domain and 63% in the change pattern domain. Most of the discordant cases were classified in neighboring categories with the majority relating to fluctuating patterns. The self-perceived overall recovery status seemed to be reflected quite well by the quantitative measures of pain intensity and days with pain in this study. Conclusion: This study shows that a real time quantitative measure (weekly SMS) and the patient's retrospective appraisal do not fundamentally differ in their reflection of the one-year course of LBP.As a first investigation into this area, these results are promising, as longitudinal quantitatively derived trajectories of LBP seem to reflect the lived experience of the patient to a large degree. Furthermore, the patient's ability to retrospectively recall their one-year course of LBP appears to be quite good. Future studies should focus on refining the categories of trajectories.