Disease Severity and Healthcare Costs Associated With Chronic Kidney Disease in Patients With Systemic Lupus Erythematosus.

PURPOSE Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by immune-mediated tissue injury. It frequently affects the kidneys, and lupus nephritis (LN) is the most severe manifestation affecting approximately 40% of patients with SLE. Persistent or inadequately managed LN can progress to chronic kidney disease (CKD) and kidney failure (end-stage kidney disease [ESKD]). Data on healthcare costs for patients with SLE and CKD are limited. The aim of this retrospective observational cohort study described the impact of CKD on clinical characteristics, healthcare costs and healthcare resource utilization (HCRU) among patients with SLE in the United States using claims data.

METHODS This retrospective, descriptive, observational cohort study (GSK Study 217378) identified patients with SLE between January 1, 2018, and December 31, 2018. Patient demographics and clinical characteristics were assessed in the 12-month baseline period preceding index (date of first SLE diagnosis [without CKD] or date of first occurrence of highest CKD stage [SLE with CKD]). HCRU and associated costs were reported for 12 months' follow-up.

FINDINGS Of 12,114 patients with SLE included in the study (2666 with CKD; 9448 without CKD), most were female, with moderate SLE. The proportion of patients with severe disease increased with advancing CKD stage (Stage 1: 23.0%-Stage 5: 77.7%). The incidence of SLE flares, renal-related events, SLE clinical manifestations and organ involvement were numerically higher in patients with versus without CKD, and increased as CKD advanced. The mean (standard deviation [SD]) number of healthcare interactions and total healthcare costs were numerically greater among patients with CKD versus without CKD (112.5 [83.3] versus 76.9 [62.1]; $59,956 [100,785] versus $31,652 [57,781], respectively). Healthcare interactions and costs appeared to increase numerically with advancing CKD (Stage 1: 84.3 [68.7]-Stage 5: 173.7 [106.9]; Stage 1: $36,417 [56,028]-Stage 5: $152,169 [177,656], respectively). Among patients with CKD, healthcare costs were largely driven by outpatient and inpatient costs.

IMPLICATIONS CKD contributes to a substantial economic burden in patients with SLE compared with those without CKD, highlighting the importance of effective screening and comprehensive SLE disease management to limit kidney complications and prevent progression to LN, CKD and ESKD.