Table 2.
Construct validity of EQ-5D-5L instrument.
| Hypothesis | EQ-5D-5L index score | EQ-5D-5L VAS score | |||
|---|---|---|---|---|---|
|
|
|
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| Spearman Correlation | Hypothesis Met | Spearman Correlation | Hypothesis Met | ||
| SF-36 PCS | Moderate (+) | 0.54* | Yes | 0.41* | Yes |
| SF-36 MCS | Moderate (+) | 0.41* | Yes | 0.60* | Yes |
| PGA | High (−) | −0.55* | Yes | −0.52* | Yes |
| HAQ-DI | Moderate (−) | −0.60* | Yes | −0.39* | Yes |
| BASDAI | Moderate (−) | −0.54* | Yes | −0.47* | Yes |
| BASFI | Moderate (−) | −0.56* | Yes | −0.44* | Yes |
| Pain | Moderate (−) | −0.59* | Yes | −0.46* | Yes |
| WPAI:SpA - absenteeism | Moderate (−) | −0.42* | Yes | −0.42* | Yes |
| WPAI:SpA - presenteeism | Moderate (−) | −0.59* | Yes | −0.53* | Yes |
| WPAI:SpA - work productivity loss | Moderate (−) | −0.59* | Yes | −0.54* | Yes |
| WPAI:SpA - activity impairment | Moderate (−) | −0.65* | Yes | −0.55* | Yes |
p<0.001 as corrected using Bonferroni’s correction as 22 a priori hypotheses were tested; (+) and (−) indicate the direction of correlations; ‘Hypothesis Met’ column indicates whether hypothesis generated prior to analysis about direction of correlation and magnitude was met in the specific variable.
BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; BASFI: Bath Ankylosing Spondylitis Functional Index; EQ-5D-5L: EuroQOL 5 Dimensions-5 Levels Questionnaire; HAQ-DI: Health Assessment Questionnaire Disability Index; PGA: patient global assessment of disease activity; SF-36 PCS: Short Form-36 Health Survey physical component summary score; SF-36 MCS: Short Form-36 Health Survey mental component summary score; WPAI:SpA: Work Productivity and Activity Impairment Questionnaire: Spondyloarthritis.