Meta-analysis: exercise therapy for nonspecific low back pain

BACKGROUND: Exercise therapy is widely used as an intervention in low back pain. OBJECTIVE: To evaluate the effectiveness of exercise therapy in adult nonspecific acute, subacute, and chronic low back pain versus no treatment and other conservative treatments. DATA SOURCES: MEDLINE, EMBASE, PsychInfo, CINAHL, and Cochrane Library databases to October 2004; citation searches and bibliographic reviews of previous systematic reviews. STUDY SELECTION: Randomized, controlled trials evaluating exercise therapy for adult nonspecific low back pain and measuring pain, function, return to work or absenteeism, and global improvement outcomes. DATA EXTRACTION: Two reviewers independently selected studies and extracted data on study characteristics, quality, and outcomes at short-, intermediate-, and long-term follow-up. DATA SYNTHESIS: 61 randomized, controlled trials (6390 participants) met inclusion criteria: acute (11 trials), subacute (6 trials), and chronic (43 trials) low back pain (1 trial was unclear). Evidence suggests that exercise therapy is effective in chronic back pain relative to comparisons at all follow-up periods. Pooled mean improvement (of 100 points) was 7.3 points (95% CI, 3.7 to 10.9 points) for pain and 2.5 points (CI, 1.0 to 3.9 points) for function at earliest follow-up. In studies investigating patients (people seeking care for back pain), mean improvement was 13.3 points (CI, 5.5 to 21.1 points) for pain and 6.9 points (CI, 2.2 to 11.7 points) for function, compared with studies where some participants had been recruited from a general population (for example, with advertisements). Some evidence suggests effectiveness of a graded-activity exercise program in subacute low back pain in occupational settings, although the evidence for other types of exercise therapy in other populations is inconsistent. In acute low back pain, exercise therapy and other programs were equally effective (pain, 0.03 point [CI, -1.3 to 1.4 points]). LIMITATIONS: Limitations of the literature, including low-quality studies with heterogeneous outcome measures inconsistent and poor reporting, and possibility of publication bias. CONCLUSIONS: Exercise therapy seems to be slightly effective at decreasing pain and improving function in adults with chronic low back pain, particularly in health care populations. In subacute low back pain populations, some evidence suggests that a graded-activity program improves absenteeism outcomes, although evidence for other types of exercise is unclear. In acute low back pain populations, exercise therapy is as effective as either no treatment or other conservative treatments