Stability of self-report measures of improvement in chronic pain: a five-year follow-up.

Seventy patients with chronic low-back pain not due to malignancy returned a questionnaire assessing functional status 5 years following treatment with epidural or subarachnoid nerve blocks. One hundred fifty-one patients had been surveyed 3 years earlier in an initial follow-up. The respondents to the present survey were older and more able to bend and took more medication for pain than non-respondents. The results revealed a tendency for gender-associated differences in improvement noted in the initial survey to be maintained, with women showing greater absolute improvement than men, particularly in vocational abilities. Men were somewhat more improved as a group on the current follow-up than on the initial follow-up. The use of medication for pain remained generally unchanged over time, but the number of respondents reporting the need for additional surgical treatments declined. The results were seen as indicating the need for using multiple, functional criteria in assessing response to treatment, including both global pain ratings and functional-behavioral measures of improvement.