Background Treatment guidelines recommend early and aggressive treatment among newly diagnosed rheumatoid arthritis (RA),1 including disease-modifying anti-rheumatic drug (DMARD) treatment initiation to potentially reduce the burden of RA.
Objectives To quantify the proportion of patients with newly diagnosed RA who had not initiated a DMARD within 12 months of RA diagnosis and explore predictors of DMARD initiation.
Methods The MarketScan Research Databases® from 2009-2012 were used to identify adults with newly diagnosed RA (index date) with at least 12 months of pre- and post-index continuous enrollment. Two RA diagnoses (ICD-9-CM 714.xx) were required within a 120 day period, with at least one claim more specific to RA (ICD-9-CM 714.0x or 714.2x). Patients with pre-index DMARD use or RA claims were excluded. Patients were categorized as DMARD initiators or non-initiators in the 12 months following the index date. Predictors for DMARD initiation were identified using logistic regression controlling for baseline demographic and clinical characteristics measured over the 12 month pre-index period.
Results A total of 40,040 newly diagnosed RA patients [72.5% female, mean age 58.6 years (SD=14.8)] met the selection criteria. Over one-half (55%) of patients initiated DMARD therapy within 12 months of RA diagnosis. Non-initiators were older [mean age 61.0 (SD=15.7) vs. 56.6 (SD=13.7)], had a higher Deyo-Charlson Comorbidity Index Score (CCI) [1.0 (SD=1.6) vs. 0.6 (SD=1.2)], and a higher proportion of infectious disease (20% vs. 14%) and cardiac conditions (24% vs. 14%) (all p<0.001).
After multivariate adjustment, predictors of DMARD non-initiation included female gender (OR: 0.96), CCI score (OR: 0.94 per point), number of baseline prescription claims (OR: 0.98 per 10 claims), and the following diagnoses: heart failure (OR: 0.76), infectious disease (OR: 0.80), liver disease (OR: 0.84), multiple sclerosis (OR: 0.65), asthma (OR: 0.89), cardiac conditions (OR: 0.86), cerebrovascular disease (OR: 0.82), dyslipidemia (OR:0.92), GI disorders (OR: 0.88), hypertension (OR: 0.88), osteoarthritis (OR: 0.89), osteoporosis (OR: 0.80) or respiratory infection (OR: 0.87). Characteristics associated with an increased likelihood of DMARD initiation included comorbid psoriasis (OR: 1.30) or diabetes (OR: 1.17), baseline receipt of a prescription NSAID (OR: 1.83), oral corticosteroid (OR: 2.20), receipt of a rheumatoid factor test (OR: 3.02) or seeing a rheumatologist for the index RA diagnosis (OR: 3.17). The majority (87%) of DMARD initiators started therapy within 90 days of diagnosis. The most commonly used DMARDs in the first 12 months were methotrexate (57%), hydroxychloroquine (29%), sulfasalazine (5%), leflunomide (3%), and etanercept (2%).
Conclusions A sizeable proportion of newly diagnosed RA patients do not initiate therapy within 12 months of diagnosis; the majority of DMARD initiators started therapy within 90 days of diagnosis.
2012 Update of the 2008 American College of Rheumatology Recommendations for the Use of Disease-Modifying Antirheumatic Drugs and Biologic Agents in the Treatment of Rheumatoid Arthritis. Arthritis Care & Research 2012; 64(5): 625–639.
Acknowledgements Research funded by Immunex Corporation, a wholly owned subsidiary of Amgen Inc.
Disclosure of Interest M. Bonafede Grant/research support from: Amgen, Employee of: Truven Health Analytics, B. Johnson Grant/research support from: Amgen, Employee of: Truven Health Analytics, N. Shah Shareholder of: Amgen, Employee of: Amgen, D. Tang Shareholder of: Amgen, Employee of: Amgen, B. Stolshek Shareholder of: Amgen, Employee of: Amgen, D. Harrison Shareholder of: Amgen, Employee of: Amgen