Effectiveness can be described as the result of a medicine’s pharmacological effect (efficacy) in interaction with different contextual factors that occur in real life. In other words, the effectiveness of a medicine can be measured when all real-life interactions occur. These interactions include effect modification, which has an impact on the treatment effect. Contextual factors that interact with the medicine’s pharmacological effect are known as drivers of effectiveness.
There are three levels of contextual factors that interact with the efficacy of a medicine, related to the:
- actual use of the medicine
- patient and disease
- healthcare system.
If drivers of effectiveness are not correctly taken into account during a medicine’s development, the effectiveness of the medicine measured in routine clinical practice may differ from that estimated during development creating an ‘efficacy-effectiveness gap’ (for a definition, see here).
The figure below illustrates how the three levels of contextual factors interact with the efficacy of a medicine, which results in the effectiveness. In reality, there are not many drivers of effectiveness, and not all interactions will be confounding variables (those that impact on the effect of the medicine).
Figure. Interactions between drivers of effectiveness and efficacy (image courtesy of Prof Abenhaim)
Ways to better understand and identify the potential drivers of effectiveness for a medicine can be found here.
Clementine Nordon and Lucien Abenhaim, LASER