A randomized controlled trial with multivariable analyses of prognostic factors.
To report the long-term outcome of McKenzie treatment compared with strengthening training. Further, to determine patient-related factors associated with poor outcome 14 months after completion of treatment.
Exercise therapy is widely recommended for patients with chronic low back pain. However, reports vary considerably concerning characteristics of patients who will not respond to treatment. Knowledge of factors associated with poor outcome may assist identification of patients requiring special attention.
A total of 260 patients with chronic low back pain were included in a previously reported randomized controlled trial of McKenzie therapy versus strengthening training. Outcome variables were: functional status, pain level, work status, and use of healthcare services during follow-up. Also, factors associated with withdrawal during the intervention were sought identified. The following factors of possible prognostic significance were determined: levels of pain and disability, pain-distribution, duration of symptoms, smoking habits, leisure activities, workload, job satisfaction, treatment preference, outcome expectations, treatment modality received, compliance with home exercises during follow-up, and demographic variables such as age, gender, work status, and application for pension. Association between variables was examined by multiple logistic regression analysis and odds ratios.
No differences in outcomes were found between the treatment groups at 14 months of follow-up. Low level of pain intensity and disability, sick leave at entry, low pretreatment expectations of future work ability, withdrawal during treatment, and discontinuance of exercises after the end of the treatment period were associated with poor outcome.
Poor long-term outcome of exercise therapy for chronic low back pain can be explained by a number of patient-related factors. Different prognostic factors were associated with different outcomes. These factors were more important in determining outcome than the exercise-programs studied.
A multiple logistic regression analysis identified prognostic factors for long-term outcome in patients with chronic low back pain treated with exercise therapy. Low level of pain intensity and disability, sick leave at entry, low expectations regarding future work ability, withdrawal during treatment, and discontinuance of exercises were associated with poor outcome.
From the *Back Center of Copenhagen, Copenhagen, Denmark; †Holstebro Hospital, Holstebro, Denmark; and ‡Department of Rheumatology, Copenhagen University Hospital, Rigshospitalet, Denmark.
Acknowledgment date: October 19, 2006. First revision date: March 21, 2007. Second revision date: June 6, 2007. Acceptance date: June 6, 2007.
Supported in part by grants from the Danish Physiotherapy Organization, Madsens Fund, and the Danish Rheumatism Association.
The manuscript submitted does not contain information about medical device(s)/drug(s).
Foundation and Professional Organizational funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.
Address correspondence and reprint requests to Tom Petersen, PT, PhD, Back Center of Copenhagen, Hans Knudsens Plads 3D, 2100 Copenhagen, Denmark; E-mail: email@example.com