Low-back pain. Factors of value in predicting outcome.

Two separate samples of 50 workers' compensation patients were assessed within 3 to 6 months of their first back injury and were reassessed at a mean of 13.7 months postinjury, at which time work status was also determined. A number of predictors on the first assessment then were correlated with return to work. These predictors included orthopaedic evaluations of severity and prognosis, the number of nonorganic physical signs, Minnesota Multiphasic Personality Inventory (MMPI) scales 1 and 3, age, education, proficiency in English, and the accuracy of patients' understanding of the bases for their medical condition as determined by the Schema Assessment Instrument (SAI). The SAI was the only variable to predict return to work significantly in both samples. These data point to the importance of patients' understanding of their medical condition for their prognosis.