Retrospective Analysis of the Impact of Adalimumab Initiation on Corticosteroid Utilization and Medical Costs Among Biologic-Naïve Patients with Rheumatoid Arthritis.

Treatment guidelines recommend low-dose corticosteroids as short-term therapy among rheumatoid arthritis (RA) patients. However, it may be difficult to wean/eliminate steroids once initiated. Initiation of more effective therapies such as biologics may help to taper corticosteroid use. The objective was to examine the impact of adalimumab (ADA) initiation on steroid utilization and non-drug medical costs among patients with RA. A retrospective analysis was conducted among adult RA patients initiating ADA as the initial biologic in the MarketScan Database (2012-2016). Study outcomes included whether oral/injectable steroids were used, daily dose, dosage categories (< 5 and ≥ 5 mg/day), number of steroid injections, and non-drug medical costs. Outcomes were compared 6 months pre- and post-ADA initiation. Mixed effects logistic, classical linear, multinomial logistic models, and linear model with a log link and gamma distribution were used to adjust for patient demographic and health characteristics. The sample included 7404 ADA initiators. Compared to pre-ADA initiation, in the post-initiation period there was a reduction in proportions of patients using oral steroids (from 71.80 to 62.56%) and injectable steroids (from 34.91 to 29.88%), average daily dose of oral steroids (from 3.30 to 2.62 mg/day), patients with dose ≥ 5 mg/day (from 21.76 to 16.34%), number of injections (from 0.64 to 0.53), and non-drug medical costs (from $5356.30 to $5146.84) (P < 0.01). The multivariate analysis produced similar patterns. For example, post-ADA initiation, patients were less likely to use oral steroids [odds ratio (OR) 0.51; 95% confidence interval (CI) 0.47-0.56]; coefficient estimate for daily dose reduction was - 0.68 (95% CI - 0.81 to - 0.56); ratio estimate for medical costs was 0.91 (95% CI 0.86-0.97). Among patients with RA, following ADA initiation, there is a reduction in steroid utilization and dosage, and non-drug medical costs. Prospective studies should be conducted to confirm this relationship in the future.