Outcome measures in chronic low back pain

Area of Science:

• Rehabilitation Medicine
• Clinical Measurement
• Pain Management

Background:

• Chronic low back pain (LBP) affects many individuals, necessitating reliable outcome measures for treatment effectiveness.
• Current instruments for measuring treatment effects in chronic LBP lack consensus on defining successful outcomes and clinically meaningful change.
• Identifying the most responsive outcome measures is crucial for accurately assessing therapeutic interventions.

Purpose of the Study:

• To determine the responsiveness of five patient-reported outcome instruments in a chronic LBP population.
• To identify which instrument best measures clinically meaningful change following a back exercise and education program.
• To compare the Minimal Clinically Important Difference (MCID) across different scales.

Main Methods:

• A prospective, single-site cohort quasi-experimental study involving 63 patients with chronic LBP.
• Administered five questionnaires (NRS, RMDQ, ODI, PSEQ, PSFS) at baseline and after a 5-week intervention.
• Utilized distribution- and anchor-based methods (SEM, ROC curves) to calculate MCID and assess responsiveness.

Main Results:

• The Patient-Specific Functional Scale (PSFS) and Pain Self-Efficacy Questionnaire (PSEQ) demonstrated higher responsiveness to clinically important changes.
• The Numerical Rating Scale (NRS) was found to be the least responsive measure.
• MCID values varied based on the calculation method (SEM vs. ROC analysis), highlighting the dependence on assessment approach.

Conclusions:

• The PSFS and PSEQ are recommended as more responsive measures for assessing change in chronic LBP patients undergoing a back class program.
• The study underscores that the MCID is not a fixed value and depends on the chosen assessment methodology.
• Results should be interpreted cautiously due to limitations including small sample size and single-center design.