The Maine-Seattle back questionnaire: a 12-item disability questionnaire for evaluating patients with lumbar sciatica or stenosis: results of a derivation and validation cohort analysis.

STUDY DESIGN

Analysis of health-related quality of life data obtained from a prospective cohort study of patients with sciatica due to an intervertebral disc herniation or lumbar spinal stenosis.

OBJECTIVE

To derive and validate a shortened version of a previously validated 23-item modification of the Roland-Morris Disability Questionnaire.

SUMMARY OF BACKGROUND DATA

For patients with low back pain, improving health-related quality of life is often the main goal of therapy. The Roland-Morris Disability Questionnaire is one of the best validated and most frequently used back-specific functional status measures. A shortened version may permit more widespread use in clinical and research settings.

METHODS

Data from 507 patients with sciatica enrolled in the Maine Lumbar Spine Study were used to derive a shortened version of a 23-item modification of the original Roland-Morris Disability Questionnaire using qualitative and cluster analysis techniques. The internal consistency, construct validity, reproducibility, and responsiveness in detecting change over a 3-month period for a new 12-item scale was compared to the original 23-item scale. The 12-item scale was then validated in an independent cohort of 148 patients with lumbar spinal stenosis.

RESULTS

Internal consistency was very good but modestly lower for the 12-item instrument compared to the 23-item original scale. Reproducibility over a 3-month interval was good and did not differ between the 12-item and original scale. Findings from the validation cohort were similar or better than the derivation cohort. A high degree of construct validity with patient-reported symptoms was demonstrated for the 12-item and original scales. The responsiveness and interpretability of the 12-item scale over 3 months was excellent and comparable to the original scale. Responsiveness assessed in patients with lumbar spinal stenosis in the independent validation cohort showed consistent findings compared to patients with a disc herniation in the derivation cohort.

CONCLUSIONS

This short, simple, self-administered 12-item back-specific functional status questionnaire performed extremely well in comparison with the original 23-item scale. If validated in additional study populations, this new questionnaire may be useful in the clinical setting as a way for providers to prospectively compare their outcomes of care to other patient populations, and to study treatment effectiveness.