Differential Psychometric Properties of EuroQoL 5-Dimension 5-Level and Short-Form 6-Dimension Utility Measures in Low Back Pain.

Methods: Prospective study. Objective: To examine the acceptability and validity of EuroQoL 5-dimension 5-level (EQ-5D-5L) and Short-Form 6-Dimension (SF-6D) health utility measures in patients with low back pain (LBP).

Background: LBP requires multiple diagnostic tests and treatment that can incur high medical costs. It is thus desirable to have an appropriate measure for cost-utility analysis of various LBP-related interventions.

Methods: Health-related quality of life (HRQoL) questionnaires including generic 12-item Short Form Health Survey (SF-12), EQ-5D-5L, and low back/back-related questionnaires were administered at a specialty clinic. SF-12 items responses were transformed to SF-6D utility scores using the Hong Kong population scoring algorithm whereas EQ-5D-5L responses were mapped onto EQ-5D-3L response, then converted to EQ-5D-5L utility scores using the Chinese-specific value set. Construct validity was determined by evaluating Spearman correlation between SF-12 and EQ-5D-5L scores. Correlation between back-specific questionnaires and HRQoL scores were assessed.

Results: A total of 100 patients were recruited. No significant (>15%) floor and ceiling effects were observed for EQ-5D-5L and SF-6D scores. Detailed proportion of respondents for each EQ-5D-5L domain indicated that Pain/Discomfort domain was the most prevalent problem. SF-6D utility score and EQ-5D-5L had respective strong (0.600-0.855) and moderate-to-strong (0.455-0.700) correlations with SF-12 domain and summary scores. EQ-5D-5L and SF-6D scores were correlated (0.625), with adequate construct validity as both utility scores conceptually measure the similar construct. Patients with no previous spine surgery nor disc degeneration had significantly higher EQ-5D-5L scores. Both EQ-5D-5L and SF-6D significantly correlated with back-specific questionnaires.

Conclusions: Both EQ-5D-5L and SF-6D appeared as applicable and valid measures in assessing HRQoL of LBP patients. Being the first study examining the differential psychometric properties and validation of the use of EQ-5D-5L and SF-6D in Chinese LBP population, this allows future exploration of the impact of utility score selection on assessing effectiveness of clinical intervention for LBP. Methods: 2.