Severe chronic low back pain was diagnosed in 236 patients by one physician and they were referred to the University of Miami Comprehensive Pain and Rehabilitation Center (UMCPRC) over a 5-year period for an intensive 4-week inpatient treatment program. Of these 143 (61%) were able to be contacted by telephone and given a structured interview designed for the study. The average time elapsed at follow-up from referral for all patients was 22.5 months. Outcome was measured in the following terms: current levels of pain, percent decrease in pain, subsequent health care utilization, activities of daily living, and attitudes toward treatment. After completion of the interview, the McGill Pain Questionnaire and the Oswestry Low Back Pain Disability Questionnaire were sent to the patients. The patients fell into five groupings: Group 1--participants in the UMCPRC program (n = 39); Group 2--those whose participation was not approved by insurance (n = 30); Group 3--those who declined participation (n = 46); Group 4--participants in other programs (n = 14); Group 5--dropouts (n = 14). The five groups were not meaningfully different with regard to prereferral demographics. Interestingly, Group 1 patients exhibited significantly greater prereferral pain and unemployment levels. Despite this, at follow-up significantly more Group 1 members were employed and they exhibited a greater percent decrease in pain as compared to the nonparticipant groups. Returned McGill and Oswestry Questionnaires mirrored these findings. Group 1 members also demonstrated significantly lower rates of subsequent health care utilization, i.e., physician visits, hospitalizations, and surgery than the nonparticipant groups.(ABSTRACT TRUNCATED AT 250 WORDS)