A head-to-head comparison of EQ-5D-5 L and SF-6D in Chinese patients with low back pain

Abstract

Background The comparative performance of the 3-level EuroQol 5-dimension and Short Form 6-dimension (SF-6D) has been investigated in patients with low back pain (LBP). The aim of this study was to explore the performance including agreement, convergent validity as well as known-groups validity of the 5-level EuroQol 5-dimension (EQ-5D-5 L) and SF-6D in Chinese patients with LBP. Methods Individuals with LBP were recruited from a large tertiary hospital in China. All subjects were interviewed using a standardized questionnaire including the EQ-5D-5 L, 36-item Short Form Health Survey (SF-36), the Oswestry questionnaire and socio-demographic questions from June 2017 to October 2017. Agreement was evaluated by intra-class correlation coefficients (ICCs) and Bland–Altman plots. Spearman’s rank correlation coefficients were applied to assess convergent validity. For known-groups validity, the Mann–Whitney U test or Kruskal-Wallis H test were used, effect size (ES) and relative efficiency (RE) were also reported. The efficiency of detecting clinically relevant differences was measured by receiver operating characteristic (ROC) curves between pre-specified groups based on Oswestry disability index (ODI), ES and RE statistics were also reported. Results Two hundred seventy-two LBP patients (age 38.1, 38% female) took part in the study. Agreement between the EQ-5D-5 L and the SF-6D was good (ICC 0.661) but with systematic discrepancy in the Bland–Altman plots. In terms of convergent validity, most priori assumptions were more related to EQ-5D-5 L than SF-6D, but MCS derived from SF-36 was more associated with SF-6D. EQ-5D-5 L demonstrated better performance for most groups except location and general health grouped by the general assessment of health item from SF-36. Furthermore, when we applied ODI as external indicator of health status, the area under the ROC curve for EQ-5D-5 L was larger than that for the SF-6D (0.892, 95% CI 0.853 to 0.931 versus 0.822, 95% CI 0.771 to 0.873), the effect size was 0.63 for EQ-5D-5 L and 0.44 for SF-6D, and it was proved that EQ-5D-5 L was 42% more efficient than SF-6D at detecting differences measured by ODI. Conclusions Both EQ-5D-5 L and SF-6D are valid measures for LBP patients. Even though these two measures had good agreement, they cannot be used interchangeably. The EQ-5D-5 L was superior to the SF-6D in Chinese low back pain patients in this research, with stronger correlation to ODI and better known-groups validity. Further study needs to evaluate other factors, such as responsiveness and reliability.

<p>Predicting EQ-5D-5L Utility Scores from the Oswestry Disability Index and Roland-Morris Disability Questionnaire for Low Back Pain</p>

“…18,20,21 Ye et al and Cheung et al used the EQ-5D-5L, but did not construct predictive models. 14,15 In addition, the variability explained by our model is very high and our results and distribution of utility scores and specific questionnaires are similar than other cohorts with the same problematic, even if it is in other regions. 14,15 Another strength is that no ceiling effect was observed in our cohort for EQ-5D-5L as in the study by Ye et al where the ceiling effect is very small (0.4%) 14 but different from Cheung et al study who have 14% for EQ-5D-5L.…”

“…This finding is consistent with two studies that found similar correlation between EQ-5D-5L and ODI. 14,15 Ye et al found a higher correlation (r=−0.828) and Cheung et al found exactly the same correlation (r=−0.770). On the other hand, we have a better correlation than other studies that had only moderate correlations around 0.5.…”

“…The correlation between EQ-5D and ODI in the literature varies from moderate [17][18][19] to high correlation. 14 To our knowledge, only one study analyzed the correlation between RMDQ and EQ-5D and found a moderate correlation. 20 Carreon et al computed a regression model to estimate EQ-5D-3L with ODI and other measures, but they did not use EQ-5D-5L and their conclusion was that the EQ-5D cannot be accurately estimated from the ODI.…”

“…The EQ-5D and SF-6D have been used and validated in different LBP populations. [13][14][15][16] To date, it is recommended to use several instruments to measure HRQoL 10 but not always done, especially in clinical studies. It is also worthwhile to note that the EQ-5D is available in two versions: EuroQol Five Dimensions Three Levels (EQ-5D-3L) and EuroQol Five Dimensions Five Levels (EQ-5D-5L).…”

“…20,21 Some authors correlated EQ-5D-5L with ODI and other measures, but did not perform regression models to predict EQ-5D-5L. 14,15 The purpose of this study is thus to evaluate if two current specific questionnaires used in CLBP (ODI and RMDQ) can be used to predict EQ-5D-5L utility scores and EuroQol Visual Analog Scale (EQ-VAS). If so, we will define the predictors of the EQ-5D-5L and establish a predictive equation.…”