Kerns, Robert D.

AbstractObjectiveChronic musculoskeletal pain (CMSP) disorders are among the most prevalent and disabling conditions worldwide. It would be advantageous to have common outcome measures when comparing results across different CMSP research studies.MethodsThe Veterans Health Administration appointed a work group to recommend core outcome measures for assessing pain intensity and interference as well as important secondary domains in clinical research. The work group used three streams of data to inform their recommendations: 1) literature synthesis augmented by three recently completed trials; 2) review and comparison of measures recommended by other expert groups; 3) two Delphi surveys of work group members.ResultsThe single-item numerical rating scale and seven-item Brief Pain Inventory interference scale emerged as the recommended measures for assessing pain intensity and interference, respectively. The secondary domains ranked most important included physical functioning and depression, followed by sleep, anxiety, and patient-reported global impression of change (PGIC). For these domains, the work group recommended the Patient-Reported Outcome Information System four-item physical function and sleep scales, the Patient Health Questionnaire two-item depression scale, the Generalized Anxiety Disorder two-item anxiety scale, and the single-item PGIC. Finally, a single-item National Health Interview Survey item was favored for defining chronic pain.ConclusionsTwo scales comprising eight items are recommended as core outcome measures for pain intensity and interference in all studies of chronic musculoskeletal pain, and brief scales comprising 13 additional items can be added when possible to assess important secondary domains.

AbstractAlthough pain reduction is commonly the primary outcome in chronic pain clinical trials, physical functioning is also important. A challenge in designing chronic pain trials to determine efficacy and effectiveness of therapies is obtaining appropriate information about the impact of an intervention on physical function. The Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) and Outcome Measures in Rheumatology (OMERACT) convened a meeting to consider assessment of physical functioning and participation in research on chronic pain. The primary purpose of this article is to synthesize evidence on the scope of physical functioning to inform work on refining physical function outcome measurement. We address issues in assessing this broad construct and provide examples of frequently used measures of relevant concepts. Investigators can assess physical functioning using patient-reported outcome (PRO), performance-based, and objective measures of activity. This article aims to provide support for the use of these measures, covering broad aspects of functioning, including work participation, social participation, and caregiver burden, which researchers should consider when designing chronic pain clinical trials. Investigators should consider the inclusion of both PROs and performance-based measures as they provide different but also important complementary information. The development and use of reliable and valid PROs and performance-based measures of physical functioning may expedite development of treatments, and standardization of these measures has the potential to facilitate comparison across studies. We provide recommendations regarding important domains to stimulate research to develop tools that are more robust, address consistency and standardization, and engage patients early in tool development.