Abstract:
Background: The Patient-Reported Outcomes Measurement Information System-29 (PROMIS-29) questionnaire assesses 7 health related quality of life domains. However, research to evaluate the responsiveness and minimal clinically important differences (MCIDs) of the PROMIS-29 scores in patients with chronic low back pain (cLBP) is limited. Purpose: To evaluate responsiveness and estimate the MCIDs for PROMIS-29 scales in patients with cLBP. Method: One hundred and eighty-three participants with cLBP took part in the study. They completed the PROMIS-29 scales at baseline, 4 weeks, and 8 weeks of the study. Responsiveness of the PROMIS-29 scale scores was evaluated by examining the mean change scores, effect sizes (ESs), standardized response means (SRMs) based on the global perceived effect (GPE) over time, including correlations with GPE. MCIDs were estimated by computing optimal cut point on the receiver operating characteristic curve and standard error of measurement (SEM) statistics for each scale. Results: The mean change scores, ESs, and SRMs increased as a function of the GPE ratings. At 4-week follow-up, the ESs and SRMs showed large magnitudes (ESs and SRMs ≥ 0.80) for Pain Intensity, Physical Function, and Anxiety scales in very much improved group. The correlations between change scores and GPE ratings were mostly weak in magnitude at 4 and 8 weeks. The MCID estimates computed as Pain Intensity 1.50 points; Physical function 3.60 points; Anxiety 5.88 points; Depression 5.25 points; Fatigue 7.75 points; Sleep Interference 3.90 points; Ability to Participate in Social Roles and Activities 4.58 points; and Pain Interference 4.85 points. Conclusion: The PROMIS-29 scale scores assessing pain intensity, physical function, and anxiety evidenced the most responsivity in the study sample.
