in clinical trials is the treatment, intervention, or standard of care used as a basis for comparison with a new treatment. When an effective therapy for a condition already exists, it is considered unethical to withhold it or give participants an ineffective substitute. Instead, new interventions are compared to the best existing treatment—often referred to as the “gold standard”—to evaluate their relative safety and effectiveness.
Synonyms: Control Treatment, Reference Arm, Control Arm
Example
In a randomized controlled trial of a new rheumatoid arthritis drug, methotrexate—the current standard of care—is used as the comparator. The new drug’s effectiveness and safety are measured against methotrexate to determine if it provides added benefit.