Changes in disability following physical therapy intervention for patients with low back pain: Dependence on symptom duration

Objectives: To assess the impact of symptom duration on functional outcome, functional improvement, pain, and patient perception of recovery after a physical therapy (PT) program for low back pain (LBP) and to determine what variables are significantly associated with improved function. Design: Retrospective case series. Setting: Outpatient setting at a tertiary care facility. Participants: Patients (N = 130) who were seen for PT between June 2003 and November 2004. Interventions: A customized rehabilitation program was developed for each patient based on examination findings and included a combination of the following interventions: mobilization/manipulation, flexibility exercises, strengthening exercises, endurance exercises, massage techniques, and heat and cold modalities. Main Outcome Measures: Functional outcome, functional improvement, perceived pain, and perceived improvement scores in the CareConnections Outcomes System (formerly TAOS) database. Results: Persons whose symptom duration was greater than 6 months had significantly less functional improvement than persons whose symptom duration was less than I month. The median percentage improvement score for perceived recovery was also significantly lower for the chronic group than for the acute group. There was no significant difference in the percentage decrease in pain among the acute, subacute, and chronic groups. In regression analyses, a model with age (P=.001), symptom duration (P=.002), and inclusion of strengthening, flexibility, and mobilization and manipulation exercises (P=.001) fit the data well and explained 55.5% of the variance in functional improvement score for all 3 groups combined. Conclusions: Patients showed improvements in function following a rehabilitation program for LBP. The functional improvement score is influenced by age, symptom duration, and inclusion of mobilization/manipulation and strengthening and flexibility exercises.