The ePRO Blueprint For Pain Trials: Optimizing Data Capture From Protocol Design To Efficacy Endpoints

The transition of clinical pain assessments to Bring Your Own Device (BYOD) formats has forced a critical re-evaluation of how we quantify the human experience of pain. For decades, the 100 mm Visual Analog Scale (VAS) was the paper-based gold standard, prized for its continuous data. However, the move to decentralized trials introduces variables that challenge the integrity of traditional spatial mapping.

Evidence suggests that for chronic pain populations, the 11-point Numeric Rating Scale (eNRS) often provides a more robust solution. By utilizing discrete integers rather than a continuous slider, the eNRS minimizes "mechanical noise" and reduces the cognitive load on patients who may face visual or motor fatigue. While the eVAS remains essential for specific dose-finding studies requiring hyper-granular sensitivity or for maintaining legacy continuity in Phase III extensions, the eNRS offers superior data completeness and simpler responder analysis. Choosing between these scales is no longer a matter of habit, but a strategic decision involving statistical power, regulatory alignment, and the practicalities of patient interaction in a digital-first landscape.