Development of a self-efficacy instrument for patients with chronic low back pain and its use as a predictor of physical therapy outcome

Chronic low back pain (CLBP) and subsequent disability have continued to increase in the Unites States despite costly intervention. Specific effective preventative measures have not been elucidated through research. Evaluation and treatment methods have also been examined, often with no one treatment found superior to another. What has been revealed is that physiological indices are poor predictors of outcome. Psychosocial variables have been more useful. The medical community, however, has been slow to include these variables in research seeking to unravel the ever-present puzzle of how to manage chronic low back pain. ^ Integration of biological, psychological, and social approaches has resulted in an 86% success rate for patients with CLBP (Hazard, 1991). As part of a biopsychosocial model, self-efficacy (SE), proposed by Bandura, has had a significant role in many programs, including smoking cessation, pain management, adherence to exercise programs, and recovery after heart attack. ^ Instruments to measure SE in physical therapy, however, are sparse. Lorig, Chastain, Ung, Shoor, and Holman (1989) developed the Arthritis Self-Efficacy Scale (ASES), supporting reliability and validity of scores. Levin, Lofland, Cassisi, Poreh, and Blonsky (1996) modified the ASES by merely substituting the words “low back pain” for “arthritis”, but found it useful only as a global measure of SE. Global SE can create problems with respect to prediction and actually obscure what is being measured (Bandura, 1986; Pajares, 1996). ^ The purpose of this study was to develop a self-efficacy instrument with reliable and valid scores for patients with CLBP. The Chronic Low Back Pain Self-Efficacy Scale (CLBPSES) addressed two major research questions: (1) Will CLBPSES scores be useful predictors of PT outcome? (2) How will the CLBPSES scores change over time? ^ The CLBPSES was given to 38 patients with low back pain for more than three months. They were treated by physical therapists in 24 outpatient clinics in 11 states. Physical therapy (PT) outcome was measured by the Revised Oswestry Low Back Pain Questionnaire (Hudson-Cook et al., 1989). Multiple regression was used to analyze the CLBPSES as a useful predictor of PT outcome. Profile plots were created to determine how scores changed over time.