Study Design. Cross-sectional cohort.
Objective. The purpose of this study is to determine whether the EuroQOL-5D (EQ-5D) can be derived from commonly available low back disease-specific health-related quality of life measures.
Summary of Background Data. The Oswestry Disability Index (ODI) and numeric rating scales (0–10) for back pain (BP) and leg pain (LP) are widely used disease-specific measures in patients with lumbar degenerative disorders. Increasingly, the EQ-5D is being used as a measure of utility due to ease of administration and scoring.
Methods. The EQ-5D, ODI, BP, and LP were prospectively collected in 14,544 patients seen in clinic for lumbar degenerative disorders. Pearson correlation coefficients for paired observations from multiple time points between ODI, BP, LP, and EQ-5D were determined. Regression modeling was done to compute the EQ-5D score from the ODI, BP, and LP.
Results. The mean age was 53.3 ± 16.4 years and 41% were male. Correlations between the EQ-5D and the ODI, BP, and LP were statistically significant (P < 0.0001) with correlation coefficients of −0.77, −0.50, and −0.57, respectively. The regression equation: [0.97711 + (−0.00687 × ODI) + (−0.01488 × LP) + (−0.01008 × BP)] to predict EQ-5D, had an R2 of 0.61 and a root mean square error of 0.149. The model using ODI alone had an R2 of 0.57 and a root mean square error of 0.156. The model using the individual ODI items had an R2 of 0.64 and a root mean square error of 0.143. The correlation coefficient between the observed and estimated EQ-5D score was 0.78. There was no statistically significant difference between the actual EQ-5D (0.553 ± 0.238) and the estimated EQ-5D score (0.553 ± 0.186) using the ODI, BP, and LP regression model. However, rounding off the coefficients to less than 5 decimal places produced less accurate results.
Conclusion. Unlike previous studies showing a robust relationship between low back–specific measures and the Short Form-6D, a similar relationship was not seen between the ODI, BP, LP, and the EQ-5D. Thus, the EQ-5D cannot be accurately estimated from the ODI, BP, and LP.
Level of Evidence: 2
In this study of 14,544 patients seen in clinic for low back complaints, a robust relationship was not found between the Oswestry Disability Index (ODI), back and leg pain scores, and the EuroQOL-5D (EQ-5D). Thus, the EQ-5D cannot be accurately estimated from the ODI, back and leg pain scores.
From the Norton Leatherman Spine Center, Louisville, KY.
Address correspondence and reprint requests to Leah Y. Carreon, MD, MSc, Norton Leatherman Spine Center, 210 East Gray Street, Suite 900, Louisville, KY 40202; E-mail: firstname.lastname@example.org
Acknowledgment date: November 15, 2013. Revision date: December 28, 2013. Acceptance date: January 2, 2014.
The manuscript submitted does not contain information about medical device(s)/drug(s).
No funds were received in support of this work.
Relevant financial activities outside the submitted work: board membership, employment, grants, travel/accommodations/meeting expenses, patents, royalties.