Avoiding Common Pitfalls in the Analysis of Observational Studies of New Treatments for Rheumatoid Arthritis

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DateAugust 31, 2013

New disease-modifying antirheumatic drugs (DMARDs), and in particular biologic agents, have revolutionized the treatment of rheumatoid arthritis (RA) in the last decade and led to significant improvements in patient outcomes. The efficacy of these treatments has been established in well-designed and -conducted randomized clinical trials (RCTs). However, although RCTs produce good evidence of efficacy, they are expensive to conduct, and thus pro- vide data on limited numbers of highly selected patients followed for short durations of time. Therefore, RCTs are often not capable of providing good estimates of harm, which may require long-term followup of large numbers of patients. In response to this deficiency, several drug and disease registries have been established to provide long- term followup on patients exposed to these new treat- ments. In addition, administrative databases have the ad- ditional advantage of large study populations, thus offering the potential to identify rare events (1). Observa- tional (i.e., nonexperimental) studies of registry data and administrative databases are useful sources of information concerning the safety of biologic agents in RA (2,3).