Papers of the Week

Drawing on advances in chronic pain metrics, a simplified Graded Chronic Pain Scale Revised (GCPS-R) was developed to differentiate mild, bothersome and high impact chronic pain. GCPS-R was validated among adult enrollees of two health plans (N=2021). In this population, the prevalence of chronic pain (pain present most or every day, prior 3 months) was 40.5%: 15.4% with mild chronic pain (lower pain intensity and interference); 10.1% bothersome chronic pain (moderate to severe pain intensity with lower life activities interference); and 15.0% high impact chronic pain (sustained pain-related activity limitations). Persons with mild chronic pain versus those without chronic pain showed small differences on ten health status indicators (unfavorable health perceptions, activity limitations, receiving long-term opioid therapy), with non-significant differences for 7 of 10 indicators. Persons with bothersome versus mild chronic pain differed significantly on 6 of 10 indicators (e.g., negative pain coping beliefs, psychological distress, unfavorable health perceptions and pain-related interference with overall activities). Persons with high impact chronic pain differed significantly from those with mild chronic pain on all 10 indicators. Persons with high impact chronic pain, relative to those with bothersome chronic pain, were more likely to have substantial activity limitations (significant differences for 4 of 5 disability indicators) and more often received long-term opioid therapy. GCPS-R strongly predicted five activity limitation indicators with area under receiver operating characteristic curve coefficients of 0.76 to 0.89. We conclude that the 5 item GCPS-R and its scoring rules provide a brief, simple and valid method for assessing chronic pain.