Long‐term medical costs and resource utilization in systemic lupus erythematosus and lupus nephritis: A five‐year analysis of a large medicaid population

OBJECTIVE: To estimate the long-term direct medical costs and health care utilization for patients with systemic lupus erythematosus (SLE) and a subset of SLE patients with nephritis. METHODS: Patients with newly active SLE were found in the MarketScan Medicaid Database (1999-2005), which includes all inpatient, outpatient, emergency department, and pharmaceutical claims for more than 10 million Medicaid beneficiaries. The date a patient became newly active was defined as the earliest observed SLE diagnosis code, with a 6-month clean period prior to the diagnosis. This method identified 2, 298 patients with a consecutive followup of 5 years. A reference group of patients without SLE was constructed using propensity score matching. Nephritis was assessed based on diagnosis and procedure codes involving the kidney. RESULTS: Mean annual medical costs for SLE patients totaled 16, 089 at year 1, which is significantly greater (by 6, 831) than that for reference patients. Costs decreased slightly at year 2 but then increased yearly at an average rate of 16% through year 5, to 23, 860. SLE patients without nephritis (n = 1, 809) had costs 967-3, 756 higher than the reference patients. SLE patients with nephritis (n = 489) had costs 13, 228-34, 907 greater than the reference group. Inpatient visits for the nephritis subgroup were 0. 6-1. 0 per capita, which are approximately twice the rate for all SLE patients and 3 to 4 times higher than the reference group. CONCLUSION: SLE is a costly condition to treat. Medical expenses incurred by SLE patients increase steadily over time, particularly for patients with nephritis.