Use of Anti-Tumor Necrosis Factor Therapy: A Retrospective Study of Monotherapy and Adherence to Combination Therapy with Non-Biologic Disease-Modifying Anti-Rheumatic Drugs

INTRODUCTION This study examined the use of anti-tumor necrosis factor (anti-TNF) monotherapy, adherence with non-biologic disease-modifying anti-rheumatic drugs (nbDMARDs) in patients receiving a combination of anti-TNF therapies and nbDMARDs, and the impact of nbDMARD adherence on anti-TNF persistence among patients with rheumatoid arthritis (RA). METHODS Patients with RA (aged ≥18 years) from a US commercial health plan with claims for anti-TNFs (2006-2010) were defined as either biologic-naive or -exposed anti-TNF initiators based on previous nbDMARD use. Adherence to nbDMARDs and anti-TNF persistence were estimated. Cox regression estimated the association between nbDMARD adherence and anti-TNF persistence. RESULTS Among 9764 patients identified (mean age 50.2 years; 78% female), 55% of biologic-naive patients and 49% of previously exposed patients initiated any combination therapy during follow-up. Among biologic-naive combination therapy patients, 53% adhered to nbDMARD therapy <80% of the time while receiving anti-TNF therapies; 33% had <60% adherence. Compared with the most adherent patients, patients adherent to nbDMARDs 20% to 79% of the time were 30% to 20% more likely to discontinue their anti-TNF therapy in the period >90 days after starting the anti-TNF therapy. This relationship was not observed for patients with nbDMARD adherence of <20% (who were less likely to discontinue their anti-TNF therapy during the first 90 days of treatment). CONCLUSION Almost one-third of patients with RA receiving anti-TNF therapy received it as pure monotherapy. About one-third of combination therapy recipients had <60% adherence to nbDMARDs. Higher nbDMARD adherence may be associated with better anti-TNF persistence after an initial treatment period.