Background/Purpose: Many treatment options are currently available to patients with rheumatoid arthritis (RA), including tumor necrosis factor inhibitors (TNFi’s). While combination therapy of TNFi’s or other biologics with a conventional synthetic disease-modifying antirheumatic drug (csDMARD; commonly methotrexate, leflunomide, sulfasalazine, or hydroxychloroquine) is thought to be the most effective treatment option, few studies have examined changes in treatment initiation over time. This study describes RA treatment patterns among patients newly initiated on biologic and non-biologic therapy over time.

Methods: This retrospective, cohort study included adult patients with RA enrolled in the Corrona RA registry who initiated monotherapy with a biologic or csDMARD or combination therapy between January 1, 2004, and December 31, 2015. Patients were required to have ≥ 6 months of follow-up time after initiation of therapy, with at least one follow-up visit. Patients could belong to one of five cohorts: TNFi monotherapy, other biologic monotherapy, csDMARD monotherapy, combination therapy with TNFi + csDMARD, or combination therapy with other biologic + csDMARD. Cohorts were defined by the first treatment initiation after enrollment into Corrona and were mutually exclusive. The primary outcome of interest was time on therapy. Time periods of interest were 2004-2007, 2008-2011, and 2012-2015; these were based on the year of enrollment into Corrona. Data were analyzed descriptively by cohort.

Results: There were 8,027 patients in this analysis. Overall, the majority of patients were female (77%), white (82%), and biologic-naïve (60%), with mean (SD) duration of RA 7.9 (9.2) years. 9.6%, 4.6%, 37.2%, 37.6%, and 11.0% of patients initiated TNFi monotherapy, other biologic monotherapy, csDMARD monotherapy, combination therapy with TNFi + csDMARD, and combination therapy with other biologic + csDMARD, respectively. Over time, treatment initiation between monotherapy and combination therapy has not changed: about half of patients initiated monotherapy and half combination therapy, mostly TNFi + csDMARD (Table). Mean CDAI at treatment initiation has remained similar within the TNFi monotherapy cohort over the three time periods. Patients who initiated csDMARD monotherapy had the lowest CDAI at treatment initiation, while TNFi and other biologic monotherapy and both combination therapy cohorts had comparable CDAI. Time on drug has remained stable for TNFi monotherapy and decreased for all other cohorts; in the most recent time period, time on drug was similar among all cohorts.

Conclusion: In the Corrona registry, over time, treatment initiation between monotherapy and combination therapy has changed little. Mean time on drug has decreased over time, likely due to the availability of more treatment options and/or the emphasis on achievement of treat-to-target goals.