JMIR Publications

ABSTRACT

Objectives While it has been well-documented that pain intensity alone is not sufficient to assess chronic pain, objective pain surface encapsulated in a digital tool might present a major interest in objective assessment of pain. Our study seeks to determine the potential added value of pain surface measurement by determining the correlation between pain surface and pain intensity in chronic pain patients. Materials and methods Two databases from observational prospective and retrospective longitudinal studies including patients with chronic pain were used in this research. Pain intensity was assessed by the Numeric Pain Rating Scale (NPRS). Pain surface (cm²) and pain typology (neuropathic vs mechanical components) was measured by a specific pain mapping digital tool (PRISMapTM). Patients were asked to draw their pain surface on a computerized tactile interface in a predetermined body (adapted from the patient’s body mass index). A color code was used to represent pain intensity (very intense, intense, moderate, mild). Simple linear regression was used to assess the proportion of variance in pain surface explained by pain intensity. Results The final analysis included 637 chronic pain patients. The percentage of variance of the pain surface explained by pain intensity was 1.24% (R²=0.0124); CI95%=[0.11%, 6.3%]. In addition, 68% of the patients used more than 1 intensity/color, among whom 38.5% used 2 intensities/colors, 19.5% used 3 intensities/colors and 10.0% used 4 intensities/colors. Discussion Our study showed that pain intensity and pain surface provide complementary and distinct information that would help to improve pain assessment. Two thirds of the cohort used two or more intensities to describe their pain. Combining pain intensity and pain surface should be strongly considered as a means of improving daily practice assessment of patients suffering from chronic pain in primary and secondary care. Fundings: The study was funded by Medtronic (ERP NM-3351). Trial Registration: PREDIBACK study was registered on clinicaltrials.gov on November 15, 2016 with the identifier NCT02964130. The protocol of the PRISMAP study was approved by the Ethics Committee of the Poitiers University Hospital (N° F20210507150101).