Acute low back pain: systematic review of its prognosis.

OBJECTIVES: To describe the course of acute low back pain and sciatica and to identify clinically important prognostic factors for these conditions. DESIGN: Systematic review. DATA SOURCES: Searches of Medline, Embase, Cinahl, and Science Citation Index and iterative searches of bibliographies. MAIN OUTCOME MEASURES: Pain, disability, and return to work. RESULTS: 15 studies of variable methodological quality were included. Rapid improvements in pain (mean reduction 58% of initial scores), disability (58%), and return to work (82% of those initially off work) occurred in one month. Further improvement was apparent until about three months. Thereafter levels for pain, disability, and return to work remained almost constant. 73% of patients had at least one recurrence within 12 months. CONCLUSIONS: People with acute low back pain and associated disability usually improve rapidly within weeks. None the less, pain and disability are typically ongoing, and recurrences are common.