To evaluate the annual direct medical cost of systemic lupus erythematosus (SLE) in Canada by disease severity and to estimate the incremental cost associated with disease severity and flares.
Medical charts of consecutive patients seen in 3 SLE-specialized treatment centers between July 2007 and June 2008 were retrospectively assessed for disease severity at baseline and for disease activity and health care resource utilization over the following 2 years (±6 months). Annual cost was stratified by disease severity at baseline. Two-year cost was compared for patients with and without flares over 2 years. Multiple linear regression was used to determine the associations between annual cost and SLE severity, and between 2-year cost and the number and type of flare (mild/moderate versus severe).
A total of 109 active SLE patients (94% women, mean age 41.4 years, mean disease duration 11.3 years, 56 patients with severe disease) were studied. The average annual direct medical cost was $10,608 Canadian (2010 dollars) and was higher for patients with severe disease, $15,048 versus $5,917 (P < 0.001). The 2-year direct cost for patients with at least 1 flare was $22,633 versus $11,113 (P = 0.028) for patients without flares. The mean incremental annual cost was $7,007 (95% confidence interval [95% CI] $3,487, $13,048) for an SLE patient with severe disease, and the 2-year mean incremental cost was $5,848 (95% CI $2,919, $8,777) for each additional severe flare.
The direct health care cost of SLE patients in Canada is influenced by disease severity and the type and frequency of flares.