OBJECTIVES: Infliximab (IFX) is a safe and efficacious treatment for rheumatoid arthritis (RA). However, IFX is underutilized. This study assessed two important contributors to underutilization, IFX treatment costs and treatment discontinuation, among RA patients from 359 U.S. hospitals in Premier Healthcare Database during 2012−2015.

METHODS: Patients aged≥ 18 years; had principal/secondary diagnosis of RA and ≥1 IFX charge at index encounter (IE); had ≥ 1 outpatient visit during 12-month look-back and ≥2 outpatient visits during 12-month follow-up were analyzed. IFX use at IE was classified as New start (no IFX during look-back) and Continued (had IFX during look-back). Costs were adjusted to 2016 U.S. dollars. Cox proportional hazard modeling was used to assess predictors of IFX discontinuation adjusting for confounders. Linear regression was used to examine trend in IFX annual cost.

RESULTS: Overall, 4,373 RA patients (2,850 New start, 1,523 Continued) were analyzed. Compared to Continued patients, New starters were more frequently to be female (78.6% vs 73.5%), non-white (25.1% vs 21.1%), and treated at non-teaching hospital (65.5% vs 57.1%). Average annual IFX cost was estimated to be $18,602 for overall sample and was higher among Continued and patients in the Midwest and Northeast. From 2012 to 2015, average annual IFX cost per patient increased $1,066 per year. New starters were more frequently to discontinue IFX than Continued peers (40.5% vs. 32.2%). Significant risk factors for IFX discontinuation included younger age, new start, having public/no insurance at IE, losing insurance coverage, and having pneumonia during follow-up. (All p<0.05)

CONCLUSIONS: Annual IFX treatment cost was high with a 5.7% yearly increase. IFX New start, younger age, loss of insurance, and infection were strong predictors of IFX discontinuation. Clinicians and pharmacists may need to monitor patients under IFX treatment more closely especially new starters to ensure that they benefit most from IFX and avoid unnecessary discontinuation.