Reliability and Validity of the Global Pain Scalewith Chronic Pain Sufferers

BACKGROUND: Many pain scales exist today; however, a comprehensive, easy-to-analyze test has yet to be available to evaluate a patient's pain and understand the sociocultural, cognitive, and affective factors contributing to a patient's overall pain experience. Many scales have attempted to create an all-encompassing pain assessment but remain incomplete in their assessment of pain and the contributing aspects of pain. OBJECTIVE: To present the Global Pain Scale (GPS) as an alternative to current pain assessments and evaluate the reliability and construct validity of the GPS. METHODS: Two hundred sixty-two undergraduates with chronic pain at a large midwestern university participated in this survey study. Participants reported in which of 14 specific body regions they have pain, the frequency of pain, and treatment history for their pain. Participants completed 4 scales--GPS, the West Haven Yale Scale (WHY), the Perceived Stress Scale (PSS), and the short form McGill (SF-MPQ)--in a randomized order. RESULTS: The GPS demonstrated high criterion validity and high construct validity (including both convergent and discriminant validity). The total GPS scale and each of the subscales were reliable. The total GPS score was significantly correlated with all other subscales, excluding those for which there is a theoretical reason for them to not be correlated with our participant population. LIMITATIONS: A sample of college students was used, thus decreasing the generalizability of these findings to patients approximating our sample. CONCLUSIONS: The GPS is a valid scale that is concise and easily interpreted. The GPS is a comprehensive assessment of pain evaluating pain, emotions, clinical outcomes, and daily activities. This may be a valuable tool for evaluation and treatment planning for interventional pain management physicians.