Background/Purpose: Health related quality of life (HRQoL) can be expressed as utility, a value anchored at 0 (death) and 1 (perfect health, forming the basis for health economic evaluations. Utilities are determined by means of a generic instrument such as Euro-QoL-5-Dimensions (EQ-5D), a questionnaire rating mobility, self-care, usual activities, pain/discomfort and anxiety/depression on a 3-level scale. Each set of responses made by the individual constitutes a “health state”, which is translated into a utility score by means of a a preference set (weights) from a reference population. Many preference sets are available based on hypothetical valuations (ratings of health states described), and the use of different weights may result in varying utility scores for the same “health state”. Recently, Swedish (SE) weights were developed using experience based valuations (rating onexs own health), and we intended to compare these to the standard, hypothetically-derived UK weights.  

Methods: Demographics, core set variables, EQ-5D and a PASS question (present state considered acceptable by patient) from patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) or spondarthritis (SpA), including ankylosing spondylitis in southern Sweden, treated with biologics, were entered into a database. EQ-5D utility employing UK and SE weights were calculated for those with complete baseline data (n=360), and the cut-off for utility PASS was determined by ROC-curves.

Results: Baseline characteristics are shown in Table 1 and PASS cut-offs in Table 2.

Conclusion: PASS does not vary appreciably between arthritis diagnoses or over time. As expected, SE utilities (experience based) are higher than UK (hypothetical). This holds true both for baseline utilities and PASS cut-off values. This difference must be accounted for in health economic evaluations and when comparing studies using different EQ-5D preference sets.