Evaluation of two time-specific back pain outcome measures

Study Design. Postal questionnaire to individuals with back pain. Objective. To assess the acceptability, validity, and reliability of two ex isting back pain outcome measures, the Roland-Morris Questionnaire and the Von Korff scales, modified to measure the preceding 4 weeks. Summary of Background Data. The ideal outcome measure for studies of low ba ck pain and disability remains elusive. Most existing measures assess curre nt pain and disability. Measuring these factors over a preceding 4-week per iod may be more appropriate. Methods. Individuals with back pain identified in a community survey were a sked to complete the modified questionnaires. Validity was assessed by comp arison with the Medical Outcome Study Short Form 36 and two general compara tor questions on self-reported pain and disability. Repeatability was asses sed using retest questionnaires. Results. Completed questionnaires were returned by 95 individuals with chro nic back pain. The modified Roland-Morris Questionnaire and Von Korff pain and Von Korff disability scales were completed satisfactorily by 83 (87%), 89 (94%), and 87 (92%) participants, respectively. Mean scores of the modif ied measures changed significantly and in a predictable manner with increas ing ratings of pain and disability. They also correlated with aspects of th e Medical Outcome Study Short Form 36 questionnaire. Retest data suggest th at these measures are repeatable. The modified Roland-Morris Questionnaire provided adequate analyzable data only if missing values were imputed, and it explained less of the variance in the comparator questions than the modi fied Von Korff scales. Conclusions. The modified Von Korff scales were completed easily and appear to be valid and repeatable in this format.