Direct and indirect costs for systemic lupus erythematosus in Sweden. A nationwide health economic study based on five defined cohorts.

Objectives: The main objectives of this study were to calculate total costs of illness and cost-driving disease features among patients with systemic lupus erythematosus (SLE) in Sweden.

Methods: Five cohorts of well-defined SLE patients, located in different parts of the country were merged. Incident and prevalent cases from 2003 through 2010 were included. The American College of Rheumatology (ACR) classification criteria was used. From the local cohorts, data on demographics, disease activity (SLEDAI 2K), and organ damage (SDI) were collected. Costs for inpatient care, specialist outpatient care and drugs were retrieved from national registries at the National Board of Health and Welfare. Indirect costs were calculated based on sickness leave and disability pensions from the Swedish Social Insurance Agency.

Results: In total, 1029 SLE patients, 88% females, were included, and approximately 75% were below 65 years at the end of follow-up, and thus in working age. The mean number of annual specialist physician visits varied from six to seven; mean annual inpatient days were 3.1-3.6, and mean annual sick leave was 123-148 days, all per patient. The total annual cost was 208,555 SEK ($33,369 = 22,941€), of which direct cost was 63,672kr ($10,188 = 7004€) and the indirect cost was 144,883 SEK ($23,181 = 15,937€), all per patient. The costs for patients with short disease duration were higher. Higher disease activity as measured by a SLEDAI 2K score > 3 was associated with approximately 50% increase in both indirect and direct costs. Damage in the neuropsychiatric and musculoskeletal domains were also linked to higher direct and indirect costs, while organ damage in the renal and ocular systems increased direct costs.

Conclusion: Based on this study and an estimate of slightly more than 6000 SLE patients in Sweden, the total annual cost for SLE in the country is estimated at $188 million (=129.5 million €). Both direct (30%) and indirect costs (70%) are substantial. Medication accounts for less than 10% of the total cost. The tax paid national systems for health care and social security in Sweden ensure equal access to health care, sick leave reimbursements, and disability pensions nationwide. Our extrapolated annual costs for SLE in Sweden are therefore the best supported estimations thus far, and they clearly underline the importance of improved management, especially to reduce the indirect costs.