USE OF THE SF-36 HEALTH-STATUS SURVEY WITH A CHRONICALLY DISABLED BACK PAIN POPULATION - STRENGTHS AND LIMITATIONS

The SF-36 is a widely used self-report health status survey. If has re peatedly demonstrated sound psychometric properties with regard to cer tain aspects of reliability and validity, and has proven effective as a means of tracking group outcomes. There were three major objectives of the present investigation: (I) to document group changes in a sampl e of chronically work disabled low back pain patients who underwent te rtiary rehabilitation; (2) to evaluate the clinical utility of the SF- 36 in measuring changes in patients as a result of treatment; and (3) to compare the SF-36 scores found for this sample to the United States norms for back pain/sciatica patients published elsewhere. All patien ts (n = 286) received an initial evaluation consisting of several asse ssment procedures, including the SF-36. First, the sample was broken d own into a ''completer'' group (n = 188), a ''noncompleter'' group (n = 31), and a ''nonstarter'' group (n 67). Next the preprogram scores f or the physical and mental component summary scales were compared to t he norms for back pain/sciatica patients. Changes in the ''completer'' group's scores from preprogram to postprogram were then examined. To assess clinical utility three additional self-report questionnaires we re correlated to the eight scales and two summary scales of the SF-36. Results revealed no statistically significant differences with regard to demographics among the three groups. The preprogram scores for the physical and mental component summary scales were significantly lower when compared to the norms for back pain/sciatica patients. Further p atients who completed the program showed improvement on the SF-36 from preprogram to postprogram administration. When the correlations betwe en SF-36 scales and other self-report questionnaires were examined, ma ny of the highest correlations were found between the self-reported pa in and disability measurements and the physical components of health o n the SF-36. In terms of clinical usefulness, the SF-36 demonstrated l imited clinical utility when attempts were made to use it on an indivi dual patient basis. This is consistent with the psychometric limitatio ns of the SF-36. Because of the brevity of each of the eight scales an d the limited number of score levels, the reliability coefficients hav e been shown to be low in other studies (20), thereby increasing confi dence intervals around an individual's scores on each of the scales.