Sex Differences in Predictors of Outcome in Selected Physical Therapy Interventions for Acute Low Back Pain
Abstract
Study Design
Secondary analysis of pooled data from 3 randomized trials.
Objective
This study investigated sex differences in response to physical therapy intervention for acute low back pain.
Methods and Measures
Subjects (n = 165) were participants in 3 randomized trials of physical therapy interventions from outpatient physical therapy clinics in the general and military communities. Subjects were randomly assigned spinal manipulation with range-of-motion exercise, lumbar stabilization exercise, or directional-preference exercise. Outcomes were measured at 4 weeks through self-report of pain intensity and pain-related disability. Sex differences were investigated with independent t tests (baseline data), 2×3 analysis of variance (4-week reductions in pain and pain-related disability), and regression models (predictors of outcome).
Results
Men and women had similar reductions of pain intensity (raw mean difference, 0.5; 95% CI, −1.4 to 0.4) and pain-related disability (raw mean difference, 5.3; 95% CI, −0.1 to 10.7) over 4 weeks. Baseline pain intensity, duration of symptoms, and baseline pain-related disability significantly predicted change in pain intensity for women (r2 = 26%, P<.01). Baseline pain intensity and stabilization exercise predicted change in pain intensity for men (r2 = 33%, P<.01). Baseline pain-related disability, duration of pain, and pain intensity predicted change in disability for women (r2 = 24%, P<.01). Baseline pain-related disability, fear-avoidance beliefs, stabilization exercise, and leg pain predicted change in disability for men (r2 = 32%, P<.01).
Conclusion
For patients with acute low back pain, men and women had similar physical therapy outcomes for reductions in pain intensity and pain-related disability. However, men and women had different factors that predicted treatment outcome. J Orthop Sports Phys Ther 2006;36(6):354–363. doi:10.2519/jospt.2006.2270
