Initial Content Validation and Roadmap for a New Patient-Reported Outcome Measure of Pain Intensity

Abstract

Measures of pain intensity (eg, numeric rating scales [NRS]) are widely used in clinical research and practice. While these measures have evidence for validity and reliability, poor standardization of instructions, and response options limits precision of pain assessment, allows for inconsistency in interpretation, and presents a challenge for comparison and aggregation of study results. Despite these pitfalls, the 0 to 10 NRS remains the most commonly used primary outcome measure in clinical trials of pain treatments and is the core measure recommended by regulatory agencies. The purpose of this study was to describe the first phase in the development of a pain intensity measure that is easily interpretable, psychometrically sound, and that adheres to FDA qualification processes. The Analgesic, Anesthetic, and Addiction Clinical Trial, Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership conducted concept elicitation interviews (N = 44; 22 with acute pain; 22 with chronic pain) to understand the patient perspective on rating pain intensity and to identify actionable suggestions for improved clarity and meaningfulness of instructions, recall periods, and response options. This article summarizes interview findings, describes how patient input and FDA feedback informed preliminary candidate measures, and provides an overview of the FDA qualification process. PERSPECTIVE: Concept elicitation interviews informed the development of content-valid candidate measures of acute and chronic pain intensity for planned use in clinical trials of pain treatments, and comprise the initial stage in FDA clinical outcome assessment qualification. Measures will subsequently be evaluated through cognitive interviews and a series of psychometric studies.

Keywords: Pain intensity measurement; acute pain; chronic pain; clinical outcome assessment; content validation.