Background The European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) recommend that rheumatoid arthritis (RA) patients should be treated to the target of low disease activity or remission with traditional and biologic disease-modifying anti-rheumatic drugs (collectively referred to as DMARDs). However, significant numbers of RA patients in the US and Canada do not receive care consistent with these recommendations.1,2
Objectives To determine the influence of patient and physician factors on the decision to adjust DMARD therapy for RA patients with moderate to high disease activity.
Methods Data was drawn from the University of Pittsburgh Rheumatoid Arthritis Comparative Effectiveness Research (RACER) observational registry (2009-12) on visits where patients had moderate to high disease activity for at least 3 months. Therapy adjustment was defined as adding, switching, or increasing the dose of DMARD therapy. Generalized estimating equations (GEE) with clustering by patient were used to assess the relationship between patient and physician factors and whether or not therapy was adjusted. After selecting a correlation structure, variables significant in univariable GEE analyses (Wald test on coefficient has p<0.2) were entered into a multivariable GEE model with logit link, then backwards selection was used to choose the final model by removing variables with p>0.05. The model controlled for patient demographic and disease characteristics: age, race, gender, RA duration, Disease Activity Score-28 joint (DAS28-CRP), Short Form 12 (SF12) physical and mental components, and Health Assessment Questionnaire (mdHAQ).
Results There were 529 visits for 348 patients with moderate to high disease activity for at least 3 months. Therapy was adjusted at 24.8% of visits. The final GEE model used an exchangeable correlation structure to account for correlation between different visits for each patient. The odds ratios (OR; [95% CI]) of adjusting therapy were decreased by older patient age (0.980; [0.961,0.999]), longer disease duration (0.980; [0.962,0.999]), years since physician medical school graduation (0.958; [0.933,0.982]), being African American (0.511; [0.276,0.946]), current use of biologic therapy (0.437; [0.263,0.728]), and lower DAS28-CRP (0.556; [0.413,0.749]).
Conclusions In the RACER observational cohort, 75.2% of RA patients with moderate/high disease activity for at least 3 months did not have DMARD therapy adjusted. Patient age, years of physician experience, duration of RA, lower DAS28, being African American, and current use of biologic therapy decreased the likelihood of therapy adjustment. While the estimated impact is milder for patient age, years of physician experience and duration of RA, the data suggests more substantial impact due to DAS28-CRP, being African American, and current use of biologic therapy. Our future research will explore how other factors such as comorbidities, prior use of DMARDs and use of corticosteroids may contribute to the observed effects.
Harrold et al (2012). Arthritis Rheum, 64(3): 630-8.
Lacaille et al (2005). Arthritis Care Res, 53(2): 241-8.
Acknowledgements Funding for the RACER registry and research personnel is provided by Genentech.
Disclosure of Interest Y. Shaw Grant/research support from: Genentech, C.-C. Chang: None Declared, H. Eng Grant/research support from: Genentech, I. Metes Grant/research support from: Genentech, L. Moreland Grant/research support from: Genentech, S. Wisniewski Grant/research support from: Genentech, M. Roberts: None Declared, M. Levesque Grant/research support from: Genentech