MEDICAL COSTS AND THEIR PREDICTORS IN KOREAN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

Abstract

Background Systemic lupus erythematosus (SLE) has very high economic burdens on society and healthcare system.Objectives The aim of this study was to estimate the annual direct costs and predictors of cost in Korean patients with SLE.Methods Total 749 patients with SLE were recruited in the Hanyang BAE lupus cohort in Seoul, Korea. We assessed the annual direct costs for the 12 months in 2010. Information was taken directly from the chart review and hospital database. And, the medication costs, which are not available from hospital database, were obtained by micro-costing methodology.Results The estimated total annual direct medical costs amounted to $3,305 (2010 US dollars), of which 60.4% was accounted for by inpatient costs and 39.6% by outpatient costs. Among the cost domains for total direct medical costs, the biggest component was the costs of medication. The mean medication costs were $1,251, which accounted for 38.4% of the total healthcare costs, followed by costs for diagnostic procedures and tests, accounting for 35.6% of the total. The annual direct medical costs increased significantly according to SLICC/American College of Rheumatology Damage Index (SDI) subgroup (total SDI=0, 1 or 2, and ≥3), both at enrollment and in 2010 (p=0.0049 vs. p<0.0001). And, the presence of renal and neuropsychiatric SDI incurred higher costs (p=0.0002 vs. p=0.0007). Total reimbursement rates of patients with SLE were 66.3%, and copayment and non-reimbursement comprised 10.8% and 22.9%, respectively. Reimbursement rates have shown a tendency to increase, whereas, out-of pocket was decreasing gradually each year between 2007 and 2010. In the multivariate regression analyses, the predictors of increased direct costs were higher disease activity (as expressed by the adjusted mean SLEDAI score), higher organ damage (as expressed by the SDI score) and renal and hematologic involvement, whereas longer disease duration predicted lower direct costs.Conclusions We have reported on the first cost-identification study in Korean patients with SLE. This analysis indicates that persons with SLE incurred a mean annual direct cost of $3,305 in 2010 US dollars. Longer disease duration predicted lower costs, whereas higher disease activity, higher organ damage, renal and hematologic involvement predicted higher costs.