title: Overlapping Chronic Pain Conditions: Implications for Diagnosis and Classification.
abstract: There is increasing recognition that many if not most common chronic pain conditions are heterogeneous with a high degree of overlap or coprevalence of other common pain conditions along with influences from biopsychosocial factors. At present, very little attention is given to the high degree of overlap of many common pain conditions when recruiting for clinical trials. As such, many if not most patients enrolled into clinical studies are not representative of most chronic pain patients. The failure to account for the heterogeneous and overlapping nature of most common pain conditions may result in treatment responses of small effect size when these treatments are administered to patients with chronic overlapping pain conditions (COPCs) represented in the general population. In this brief review we describe the concept of COPCs and the putative mechanisms underlying COPCs. Finally, we present a series of recommendations that will advance our understanding of COPCs.
  
  
  
  This brief review describes the concept of COPCs. A mechanism-based heuristic model is presented and current knowledge and evidence for COPCs are presented. Finally, a set of recommendations is provided to advance our understanding of COPCs.
authors: Center for Pain Research and Innovation, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Center for Translational Pain Medicine, Department of Anesthesiology, Duke University, Durham, North Carolina. Electronic address: william.maixner@duke.edu.
authors: William
authors: W
authors: Maixner
authors: Pain Research and Intervention Center of Excellence, University of Florida, Gainesville, Florida.
authors: Roger B
authors: RB
authors: Fillingim
authors: Chronic Pain and Fatigue Research Center, Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan.
authors: David A
authors: DA
authors: Williams
authors: Center for Pain Research and Innovation, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Center for Translational Pain Medicine, Department of Anesthesiology, Duke University, Durham, North Carolina.
authors: Shad B
authors: SB
authors: Smith
authors: Center for Pain Research and Innovation, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Dental Ecology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
authors: Gary D
authors: GD
authors: Slade
mesh_terms: D002908:Chronic Disease; D059350:Chronic Pain / Q000145:classification* / Q000175:diagnosis* / Q000628:therapy; D019317:Evidence-Based Medicine; D006801:Humans; D059408:Pain Management; D010147:Pain Measurement / Q000379:methods*
keywords: Overlapping conditions; classification; diagnosis; genetic factors; pain sensitivity; psychological factors