1882 - An Evaluation of the Extended Item Euroqol Compared with the Standard Euroqol

Tuesday, November 8, 2011: 9:00 AM-6:00 PM
Hall F2 - Poster Hall (McCormick Place West)
Kaleb Michaud, National Data Bank for Rheumatic Diseases & University of Nebraska Medical Center, Omaha, NE and Frederick Wolfe, National Data Bank for Rheumatic Diseases, Wichita, KS
Presentation Number: 1882

Background/Purpose: The EuroQoL (EQ5D) is a widely used health-related quality of life utility scale that is frequently used in cost-effectiveness analyses. It is composed of 5 questions, 3 relating to function, 1 to pain, and 1 to mood. The EQ5D is limited because each question has only 3 levels: the worst possible condition, the best possible condition, and a single level in between. Since the worst level is rarely endorsed, each question effectively has two levels: perfectly normal or not perfectly normal. The limited range also results in a reduced sensitivity to change. The EuroQol Group recently developed a new scale (EQ5D-5L) in which each question contains 5 levels, thereby potentially increasing sensitivity and capturing a wider range of symptoms. A central question regarding the 2 scales is whether they yield similar results, and whether the new questionnaire has better performance characteristics.

Method: We administered the EQ5D, EQ5D-5L and other rheumatic disease questions to 6,824 patients as part of a semi-annual long-term rheumatic disease outcome study.

Result: The Pearson correlation between the EQ5D questionnaires was 0.827, and Lin's concordance coefficient was 0.817. The average difference between questionnaires was 0.008, and the 95% limits of agreement was -0.206 to 0.190. The EQ5D-5L had a smoother and more continuous distribution, but questionnaires differed most at extreme values (Figure 1). The EQ5D-5L was more strongly correlated with all measures than the EQ5D (Table 1), and the EQ5D-5L provided a much better model fit as assessed by the Bayesian and Akaike Information coefficients. The EQ5D-5L/EQ5D mean (SD) values were: rheumatoid arthritis 0.751/0.761 (0.152/0.176), lupus 0.754/0.765 (0.172/0.189), fibromyalgia 0.666/0.666 (0.167/0.196) and osteoarthritis 0.745/0.751 (0.139/0.165). As suggested by Figure 1, the EQ5D has slightly higher scores compared to the EQ5D-5L in illnesses with better quality of life and equivalent scores in lower QOL disorders such as fibromyalgia.

Questionnaire

EQ5D-5L

EQ5D

EQ5D-L (0-1)

1.000

0.827

EQ5D (0-1)

0.827

1.000

Patient activity score (PAS) (0-10)

-0.781

-0.755

HAQ (0-3)

-0.709

-0.666

Global severity (0-10)

-0.673

-0.650

Pain (0-10)

-0.669

-0.665

Physical component score (SF-36)

0.665

0.629

Polysymptomatic distress scale

-0.648

-0.626

Fatigue (0-10)

-0.604

-0.576

Mood (0-10)

-0.525

-0.511

Sleep disturbance (0-10)

-0.494

-0.472

Mental component score (SF-36)

0.490

0.480

EuroQoL VAS (0-100)

0.484

0.456

Comorbidity Index (0-9)

-0.327

-0.309

Sex

0.067

0.050

Age (years)

0.061

0.039

Conclusion: The EuroQol scales provide similar mean scores and are well correlated. The EQ5D-5L provides a much better model fit, lower variance and greater correlation with clinical variables. The EQ5D-5L should be substituted for the older EQ5D version to provide a better assessment of health utility.


Keywords: quality of life and questionnaires

Disclosure: K. Michaud, None; F. Wolfe, None.