Article Text

SAT0315 Comparison of the euroqol and short form 6D in multiethnic asian patients with psoriatic arthritis
  1. Y.Y. Leung1,
  2. M.E. Png1,
  3. H.L. Wee2,
  4. J. Thumboo3
  1. 1Rheumatology & Immunology, Singapore General Hospital
  2. 2Pharmacy, National University of Singapore
  3. 3Rheumatology & Immunology, Duke-NUS Graduate Medical School, Singapore, Singapore


Objectives To compare EuroQol (EQ-5D) and Short form 6D (SF-6D) utility scores among multiethnic Asian patients with psoriatic arthritis (PsA).

Methods Consecutive patients fulfilling the Classification Criteria for Psoriatic Arthritis (CASPAR) for PsA and attending a tertiary rheumatology outpatient clinic were invited to complete identical English or Chinese questionnaires of EQ-5D and SF-6D and assessing socio-demographic characteristics. Utility scores were calculated using the scoring algorithms developed from the UK general population. Comparisons between the 2 instruments were performed by their score distributions, means, medians, intraclass correlation coefficients (ICCs) and Bland-Altman plot.

Results Subjects (n=86, 69 English and 16 Chinese speaking, male to female ratio 0.91) participated. Mean age (±SD) and duration of illness (±SD) were 49.1 (±13.4) and 7.1 (±8.2) years. The score distribution for SF-6D was normal while that of EQ-5D was bimodal. Ceiling and floor effects were observed in 2.3% and 20% for EQ-5D and none for SF-6D. Moderate correlations are demonstrated between the 2 scores on scale level (range 0.44-0.59) and domain level (range 0.33-0.53). The mean (±SD) EQ-5D and SF-6D utility scores were 0.74 (±0.24), [range -0.16-1.00] and 0.68 (±0.13), [range 0.36-1.00]; (p=0.001). Every 10-point increase in EQ-5D health state VAS was associated with a 0.07 and 0.04 quality-adjusted life year (QALY) gain if using EQ-5D and SF-6D respectively. EQ-5D generated higher utility scores than SF6D in subgroup with better health, and the opposite occurred in less healthy subgroup. Poor agreements between EQ-5D and SF-6D utility scores were demonstrated with the low ICC (0.43) and the Bland-Altman plot.

Table 1. Comparison of EQ-5D and SF-6D utility scores for patients and subgroups

Conclusions Using different preference-based health-related quality of life instruments yield different utility scores, which may have a great impact on QALY estimates. This highlights the importance of choosing the appropriate instrument for cost-effectiveness evaluation. Additional research is needed to determine if EQ-5D or SF-6D is the better instrument for PsA.

Disclosure of Interest None Declared

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