OBJECTIVES: To describe health resource utilization (HRU) patterns among patients with systemic lupus erythematosus (SLE) prescribed belimumab in U.S clinical practice settings. METHODS: OBSErve (BLM117295) is a multi-center retrospective medical chart review study. Ninety-two rheumatologists from non-academic-centers in the U.S randomly identified adult SLE patients in their practice who had received at least 8 infusions of belimumab (10mg/kg) as part of usual-care. Index-date is the date of the first belimumab infusion. Physicians assessed the following data corresponding to the 6 months pre- and post-index periods: patient demographics, comorbidities, SLE disease characteristics/outcomes, and HRU (hospitalization/ER/office-visits, ancillary care (physical/occupational therapy/home health), medications). Patterns of HRU in the 6 months pre- and post-index period are reported from univariate (comparative) analysis  and two-sided tests of significance (p<0.05). RESULTS: Physicians abstracted 501 eligible patient-charts (mean age:41.3yrs, female:89%, Caucasian:53%, black/African-American:24%, Hispanic:18%, other:5%; Medicare:13%, Medicaid:14%, commercial-insurance:62%; diagnosed with SLE <5 yrs ago:56%); 3%/77%/20% had mild/moderate/severe disease at baseline, per physician judgment. In the pre-index period, concomitant medications included oral steroids(78%), antimalarials(70%), immunosuppressants(61%) and NSAIDs(16%). In post-index period, among those on oral steroids, 9% discontinued steroids and 77% decreased the dose. Percentage of patients with >1 hospitalization (pre-index:5%;post-index:2%;p=0.03), >1 ER visits (pre-index:15%;post-index:6%;p=0.001), >1 unscheduled treating physician visits (pre-index:52%;post-index:30%;p<0.001), and those receiving any ancillary care (pre-index:15%;post-index:6%;p=0.001) decreased from pre-index to post-index period. The mean number of hospitalizations (pre-index:0.6;post-index:0.2;p=0.02), ER visits (pre-index:0.2;post-index:0.07;p<0.001), unscheduled visits to treating physician (pre-index:1.0;post-index:0.5;p<0.001) and visits to other specialty physicians (pre-index:2.0;post-index:1.4;p=0.001) also decreased from pre-index to post-index period. CONCLUSIONS: Resource utilization decreased in a sample of belimumab treated patients in the first 6-months, in comparison to the pre-index period. Association of these observed HRU patterns with clinical outcomes and the implications of these observed HRU patterns for payers warrants further study.