Economic and humanistic burden of post-trauma and post-surgical neuropathic pain among adults in the United States

Bruce Parsons,¹ Caroline Schaefer,² Rachael Mann,³ Alesia Sadosky,¹ Shoshana Daniel,⁴ Srinivas Nalamachu,⁵ Brett R Stacey,⁶ Edward C Nieshoff,⁷ Michael Tuchman,⁸ Alan Anschel<sup>9

1</sup>Pfizer, Inc, New York, NY, USA; ²Covance Market Access Services, Inc, Gaithersburg, MD, USA; ³Covance Market Access Services, Inc, San Diego, CA, USA; ⁴Covance Market Access Services, Inc, Conshohocken, PA, USA; ⁵International Clinical Research Institute, Overland Park, KS, USA; ⁶Oregon Health and Science University, Portland, OR, USA; ⁷Rehabilitation Institute of Michigan/Wayne State University, Detroit, MI, USA; ⁸Palm Beach Neurological Center, Palm Beach Gardens, FL, USA; ⁹Rehabilitation Institute of Chicago, Chicago, IL, USA

Background: Neuropathic pain (NeP) can be chronic, debilitating, and can interfere with sleep, functioning, and emotional well being. While there are multiple causes of NeP, few studies have examined the disease burden and treatment patterns associated with post-traumatic/post-surgical (PTPS) NeP.
Objective: To characterize pain, health status, function, health care resource utilization, lost productivity, and costs among subjects with PTPS NeP in the United States.
Methods: This observational study enrolled 100 PTPS NeP subjects recruited during routine visits from general practitioner and specialist sites. Subjects completed a one-time questionnaire with validated measures of pain severity and pain interference, health status, sleep, anxiety and depression, productivity, and study-specific items on demographics, employment status, and out-of-pocket expenses. Investigators completed a case report form based on a 6-month retrospective chart review, recording subjects' clinical characteristics as well as current and previous medications/treatments for NeP. Subjects were stratified into mild, moderate, and severe pain groups.
Results: Subjects' demographic characteristics were: mean age of 54.9 years, 53% female, and 22% employed for pay. Mean pain severity score was 5.6 (0–10 scale), with 48% and 35% classified as having moderate and severe pain, respectively. The mean number of comorbidities increased with greater pain severity (P = 0.0009). Patient-reported outcomes were worse among PTPS NeP subjects with more severe pain, including pain interference with function, health state utility, sleep, and depression (P < 0.0001). Eighty-two percent of subjects were prescribed two or more NeP medications. The total mean annualized adjusted direct and indirect costs per subject were $11,846 and $29,617, respectively. Across pain severity levels, differences in annualized adjusted direct and indirect costs were significant (P < 0.0001).
Conclusion: PTPS NeP subjects reported high pain scores, which were associated with poor health utility, sleep, mood, and function, as well as high health care resource utilization and costs. The quality of life impact and costs attributable to PTPS NeP suggest an unmet need for effective and comprehensive management.

Keywords: trauma/surgery, neuropathic pain, quality-of-life, patient-reported outcomes, costs, productivity