Total cost and cost predictors in systemic lupus erythematosus-8-years follow-up of a Swedish inception cohort

Objective To study the annual direct and indirect costs in systemic lupus erythematosus (SLE) and how age, disease manifestations, disease activity, and organ damage influence total costs and predicted costs for SLE. Methods Clinical data on all patients with a diagnosis of SLE living in a defined area in southern Sweden during eight years were linked to health authority registries and the social insurance system which contain data on cost. Cost data on four matched population controls for each patient were also extracted. The controls were matched for age, sex, and area of residence. Results Data from 127 patients with SLE and 508 population controls were extracted. The mean annual total cost for SLE patients was SEK 180,520 ($30,093); the highest costs were found in the subgroup with nephritis SEK 229,423 ($38,246). The total costs for the patient group were significantly higher (p<0.05) compared to the population controls of SEK 59,985 ($10,000). Of the total costs, 72% were due to indirect costs, 3% to SLE-specific pharmaceuticals, and the remaining 25% were in- and outpatient related costs. During the study period, inpatient days decreased by 60%, while outpatient contacts increased by 25%. Age (inverse relation), increasing disease activity, and acquired organ damage were significant predictors of total costs (all p<0.05). Conclusion The total annual costs for unselected SLE patients were found to be three times those for matched population controls. Important predictors of total costs were found.