Study design: Descriptive prognostic study.
Objectives: To identify outcome determinants of subacute low back pain.
Summary of background data: The factors predicting recovery from prolonged back pain among working adults are largely unknown.
Materials and methods: One hundred sixty-four employed patients with subacute (duration of pain 4-12 weeks) daily low back pain were recruited from primary health care to a randomized study. Data on potential predictive factors were collected before randomization. In multiple regressions using repeated measures analysis, the treatment received was adjusted when determining the impact of the predictive factors. Dependent outcome variables used were pain, perceived functional disability, generic health-related quality of life, satisfaction with care, days on sick leave, use of health care, and costs of health care consumption measured, at 3-, 6-, and 12-month follow-ups.
Results: Age and intensity of pain at baseline predicted most of the outcomes. The perceived risk of not recovering was a stronger determinant of outcome than gender, education, or self-rated health status (which did not have any predictive value) or body mass index, expectations of treatment effect, satisfaction with work, or the presence of radicular symptoms below the knee (only slight predictive value). The only factors predicting the duration of sick leave were the duration of sick leave at baseline and the type of occupation.
Conclusion: Age and intensity of pain are the strongest predictors of outcome. Accumulation of days on sick leave is predicted by the duration of sick leave at entry and the type of work, but not by pain, perceived disability, or satisfaction with work.