Phase 2 Assessment of a New Functional Pain Scale by Comparing It to Traditional Pain Scales

Background Assessment of pain has always been subjective and is commonly assessed using a numeric pain scale (NPS) or Wong-Baker faces scale. The pain intensity score is not standardized and relies on individuals' past experiences. The disadvantage of using such pain assessment scales and treating the numbers can lead to overdosing on analgesics leading to unwanted side effects. The Robert Packer Hospital/Functional Pain Scale (RPH/FPS) was developed as a tool for the objective assessment of pain and its impact on a patient's function.  Aim The study aimed to validate the RPH/FPS scale against NPS and Wong-Baker faces scale in medical, surgical, and trauma patients. The patients' were also asked to rank the scales as one (1) being the most preferred to three (3) being the least preferred. Design This prospective, observational cohort study compares the two most common pain scales, the NPS and the Wong-Baker Faces, to the RPH/FPS. Methods Spearman correlation was used to test for correlation between the three scales, and Wilcoxon rank-sum test was used to compare means between the RPH/FPS and NPS. The study participants were also asked to rate their preferences for the scales by rating the most preferred of the three scales as one (1) and the least preferred number three (3).  Results The RPH/FPS had a strong correlation with both the NPS and Wong-Baker Faces scales (RPH/FPS vs. NPS R=0.69, p<0.001: RPH-FPS vs. Wong-Baker Faces R=0.69, P<0.001). As for preferences, the RPH/FPS was ranked first on 36.9% of the surveys followed by NPS on 35.9%, and the Wong-Baker Faces on 22.3%. There were 4.9% of the surveys missing the preference rankings. Conclusion The results validate the RPH/FPS scale against the NPS and Wong-Baker Faces scales. This gives the clinicians a tool for objective assessment of pain and its effect on the recovery process, thereby minimizing the observed disconnect that sometimes happens between the reported pain intensity level and the providers' observation of the patient.