Background/Purpose:  In a time of increasing economic constraints, it is crucial that health systems optimize their resource use to ensure that they generate the maximum possible health gain. Therefore, it is necessary for health interventions to be evaluated and compared across therapeutic boundaries. Undertaking such an evaluation requires a generic utility-based measure. But it remains uncertain whether the utility values obtained by direct or indirect methods are comparable and which approach is the most appropriate in Systemic Lupus Erythematosus (SLE) population. The objective of this study was to compare the utility values obtained using an indirect method based on the EuroQol scale (EQ-5D) and direct utility instruments, the standard gamble (SG) and visual analog scale (VAS), in patients with SLE.

Methods: 240 consecutive patients with stable SLE underwent assessment of disease activity SLE Disease Activity Index (SLEDAI)] and damage [Systemic Lupus Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR DI)] and completed a disease-specific health-related quality of life (HRQoL) measure, LupusQoL, and 3 utility measures: VAS, SG, and EQ-5D. Pearson’s correlations were calculated between the LupusQol domains and the utility measures to assess validity. To assess reliability, intraclass correlations or kappa coefficients were calculated between first and second assessments, performed from 2 weeks apart, in patients without important clinical change in disease activity. Multiple regression models were performed for VAS and SG to determine predictor of utility.

Results:  Disease activity from SLEDAI varied from 0 to 25 (median = 2). All domains of the LupusQoL correlated well with the VAS [r: 0.329-0.632, 95% confidence interval (CI) (0.30, 0.56)] and EQ-5D value [r: 0.299-0.757, 95%CI (0.35, 0.69)] except body image (r=0.162 and 0.165, p=0.018 and 0.016, respectively), and poorly with the SG [maximum r = 0.360, CI (0.0, 0.375); minimum r = 0.044, CI (0.0, 0.375)]. Test-retest reliability intraclass correlations for the VAS [ICC = 0.793, 95% CI (0.707, 0.856)], SG [ICC=0.770, 95% CI (0.676, 0.839)] were good. The kappa coefficient was poor (0.284) for the EQ-5D domain of Anxiety/Depression, but excellent (Mobility: 0.786; Self-care: 0.849; Usual activities: 0.972; Pain/Discomfort: 0.796) for the remaining domains. A model incorporating the SLEDAI score and LupusQoL domains of emotional health and pain were good predictors of VAS (R²=0.56) and SG (R²=0.221) utility measures.

Conclusion:  The VAS, EQ-5D, and to some extent, SG, when compared with the disease-specific HRQoL survey LupusQoL, are valid and reliable measures to assess HRQoL in a group of patients with SLE and have emerged as promising outcome measures for future research in this population. It may also be used as a basis for further studies to obtain utility data with larger samples across SLE patients and provide helpful information to seek for theoretical basis for reasonable allocation of health resources.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-cornerstone-to-reasonable-allocation-of-health-resource-valuation-of-health-utility-in-systemic-lupus-erythematosus/