Treat-to-target end points for systemic lupus erythematosus (SLE) have been assessed for their impact on damage accrual and flare, but whether they have an impact on the high health care utilization and costs in SLE has not been studied. The purpose of this study was to examine our hypothesis that the recently described lupus low disease activity state (LLDAS) would be associated with reduced health care cost.
Data from a single tertiary hospital longitudinal SLE cohort were assessed. Baseline demographics, disease activity (Systemic Lupus Erythematosus Disease Activity Index 2000 [SLEDAI-2K], physician global assessment [PhGA], and flare index), and medication use were evaluated, and direct health care utilization and cost data were obtained from hospital information systems. LLDAS was defined as previously published: briefly, SLEDAI-2K ≤4 with no new activity, PhGA ≤1, prednisolone ≤7.5 mg/day, and optimal standard immunosuppressive agents. Analysis was performed using multivariable linear regression.
Two hundred SLE patients, contributing 357.8 person-years of observation, were included. A history of lupus nephritis was present in 42% of patients, and damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index >0) was present at study commencement in 57.3% of patients. The mean ± SD annual direct medical cost per patient was US$7,413 ± 13,133/year. In multivariable analysis, increased cost was associated with the presence of baseline organ damage (41.7% increase; P = 0.009) and corticosteroid use (>7.5-15 mg/day: 55.7% increase; P = 0.02; and >15 mg/day: 202% increase; P < 0.001). In contrast, spending ≥50% of the observation period in LLDAS was associated with a 25.9% reduction in annual direct medical cost (P = 0.04).
Greater time spent in LLDAS was associated with significantly reduced direct hospital health care costs among patients with SLE.