OBJECTIVES: Oral glucocorticoids (OGCs) have therapeutic benefits in rheumatoid arthritis (RA), but can produce adverse effects. This study examined the association between rituximab adherence and OGC use reduction in RA patients. METHODS: Retrospective study using a large U.S. claims database. Patients included for study had initiated rituximab between March 1, 2006-March 31, 2011 (initiation date=index), had pre-index exposure to anti-tumor necrosis factor-alpha (anti-TNF) therapy, were aged ≥18 years, had a medical claim with a diagnosis code for RA (ICD-9-CM 714.0x) between January 1, 2004-March 31, 2011, were continuously enrolled for 12 months before and ≥270 days after index, and had OGC use ≤30 days before index. Patients were excluded if they had medical claims with diagnosis codes for non-RA indications of biologic disease modifying antirheumatic drugs (BDMARDs). Based on rituximab infusion services dates and recommended 6-month reinfusions, rituximab exposure periods were constructed to start upon index and end at the first occurrence of switch to a different BDMARD, disenrollment from health insurance, reaching March 31, 2011 or follow-up of 36 months. Exposure periods were subdivided into a quarterly (90-day) repeated-measures panel dataset. Within each quarter-panel, OGC use and rituximab adherence, measured using the proportion of days covered (PDC), were measured. Multivariable generalized estimating equation models examined the association between quarterly OGC use and prior quarter (lagged) PDC, adjusting for confounding variables. Multivariable-adjusted OGC use probabilities were predicted by PDC level (PDC=0 [i.e., reinfusion≥90 days late]; PDC=50 [reinfusion=45 days late]; PDC≥100 [reinfusion=on time/early]) using the G-computation method. RESULTS: Sample comprised 4,583 quarter-panels (594 unique patients); mean age 55 years, 81% female. The multivariable-adjusted OGC use probabilities decreased with time (p<0.001) and increasing PDC (p=0.006): from approximately 0.72 for all PDC levels in the first quarter-panel to 0.64 (PDC=0), 0.55 (PDC=50), and 0.47 (PDC≥100) in the last (12th) quarter-panel. CONCLUSIONS: Increasing rituximab adherence was associated with statistically significant OGC use reduction over time.