Retrospective Analysis of Disease Severity, Health Care Resource Utilization, and Costs Among Patients Initiating Belimumab for the Treatment of Systemic Lupus Erythematosus

Purpose: The goal of this study was to evaluate clinical and economic outcomes associated with the initiation of intravenous (IV) belimumab for the treatment of systemic lupus erythematosus (SLE) in clinical practice in the United States.

Methods: This retrospective study used administrative claims data from the IBM MarketScan Commercial Claims and Encounters Database and the Medicare Supplemental and Coordination of Benefits Database. Data for patients with SLE who initiated (index) IV belimumab were collected for the 12 months before (pre-index) and the 12 months after (post-index) belimumab initiation. Outcomes included SLE disease severity and flares, all-cause health care resource utilization (HCRU) and health care costs, and hospital-based costs and service visits. Post hoc analyses of total hospital-based costs were conducted to further explore drivers of mean post-index costs.

Findings: Baseline characteristics (N = 908) are as follows: female, 93.4%; mean (SD) age, 45.6 (11.9) years; mean Charlson Comorbidity Index score, 0.9 (2.0); and moderate or severe disease, 94.9%. Disease activity (SLE flare episodes) was significantly reduced between the pre-index and post-index periods (severe flares, 16.4% vs 10.1% [P < 0.0001]; moderate flares, 92.1% vs 85.6% [P < 0.0001]; and mild flares, 77.4% vs 71.1%; [P = 0.0003]). The proportion of patients receiving oral corticosteroids (OCS) was reduced between the pre-index and post-index periods, especially among patients at higher OCS thresholds (prednisone-equivalent dose: ≥60 mg/d, 7.3% vs 4.2%; >40 mg/d, 14.1% vs 7.9%). From the pre-index to the post-index period, few differences in HCRU were observed, although all-cause physician office visits, outpatient visits, and unique prescriptions filled increased significantly. In the 12-month post-index period, patients had a mean of 12.2 (9.0) encounters (eg, outpatient visit or prescription) associated with IV belimumab. All-cause total, medical, and pharmacy costs increased from the pre-index to the post-index period. Mean all-cause hospital-based costs increased from the pre-index to the post-index period ($7735 [26,603] vs $11,030 [88,086]; P = 0.396). However, the 75th, 90th, and 95th percentile costs decreased from the pre-index to the post-index period ($305, $2107, and $3861, respectively).

Implications: After initiation of IV belimumab, disease activity (number of moderate and severe SLE flares) and use of OCS were significantly reduced. However, HCRU and costs, including hospital-based costs, were generally greater in the post-index period. Further studies will increase understanding of SLE, with the specific goals of incorporating disease activity measures and long-term outcomes in studies of HCRU, costs, and patient outcomes.