Is a condition-specific instrument for patients with low back pain/leg symptoms really necessary? The responsiveness of the Oswestry Disability Index, MODEMS, and the SF-36

Spine (Phila Pa 1976). 2003 Mar 15;28(6):607-15. doi: 10.1097/01.BRS.0000050654.97387.DF.


Study design: Analysis of longitudinal data collected prospectively from patients seen in 27 National Spine Network member centers across the United States.

Objective: To evaluate the responsiveness of the Oswestry Disability Index, MODEMS scales, and all scales and summary scales of the MOS Short-Form 36 (SF-36) for patients with low back pain/leg symptoms.

Summary of background data: The responsiveness of general and condition-specific health status instruments is a key concept for clinicians and scientists. Various authors have explored responsiveness in common surveys used to assess spine patients. Although it is generally believed that condition-specific measures are more responsive to change in the condition under study, in the case of low back pain, most authors agree that further exploration is necessary.

Methods: Patients with diagnoses of herniated disc, spinal stenosis, and spondylosis from the National Spine Network database who completed baseline and 3-month follow-up surveys were analyzed. Patient-provider consensus regarding improvement, worsening, or no change in the condition was selected as the external criterion. Responsiveness was evaluated using ROC curve analysis and effect size calculations.

Results: Nine hundred and seventy patients had complete data at baseline and 3 months. At follow-up, 68% of the patients had consensus improvement. Based on ROC analysis, scales assessing pain were significantly more responsive than scales assessing function. There were no significant differences between the condition-specific scales and their equivalent general-health counterpart. The scales with the highest probabilities of correctly identifying patient's improvement were: the condition-specific pain scale from MODEMS (PAIN, ROC = 0.758); the combined pain and function scale from MODEMS (MPDL, ROC = 0.755); the general pain scale from the SF-36 (BP, ROC = 0.753); the combined pain and function scale from the SF-36 (PCS, ROC = 0.745); the condition-specific function measure from the Oswestry (ODI, ROC = 0.723); and the physical function measure from the SF-36 (PF, ROC = 0.721). A similar rank order was typically maintained with effect size calculations. Results were nearly identical in patients with multiple non-spine-related comorbidities and in patients with high degrees of perceived disability. The BP scale was most responsive to worsening of symptoms.

Conclusion: For studies of patients with low back problems, the general SF-36 may be a sufficient measure of health status and patient function, without the need for additional condition-specific instruments. Pain scales appear to be the most responsive measures in patients with low back pain.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cohort Studies
  • Comorbidity
  • Databases, Factual / statistics & numerical data
  • Disability Evaluation*
  • Female
  • Health Status Indicators*
  • Humans
  • Intervertebral Disc Displacement / diagnosis
  • Intervertebral Disc Displacement / epidemiology
  • Longitudinal Studies
  • Low Back Pain / diagnosis*
  • Low Back Pain / epidemiology
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care*
  • Pain Measurement
  • Predictive Value of Tests
  • Prospective Studies
  • ROC Curve
  • Reproducibility of Results
  • Sciatica / diagnosis*
  • Sciatica / epidemiology
  • Sensitivity and Specificity
  • Spinal Osteophytosis / diagnosis
  • Spinal Osteophytosis / epidemiology
  • Spinal Stenosis / diagnosis
  • Spinal Stenosis / epidemiology
  • Surveys and Questionnaires / standards*
  • United States / epidemiology