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ISSUE NO 4 9 NEWS & REVIEWS CHRONIC PAIN DEFINITION – INTRODUCING THE RISK SCORE APPROACH Professor Joseph Pergolizzi Traditionally the definition of chro- nic pain has been based on dura- tion. The IASP defines chronic pain as “…pain which persists past the normal time of healing… With non- malignant pain, three months is the most convenient point of division between acute and chronic pain...” Defining chronic pain solely by du- ration is based on the view that acute pain results in potential tis- sue damage, whereas chronic pain results from central and peripheral sensitization which remains after nociceptive inputs have diminished. This view does not indicate whe- ther long-lasting pain is clinically significant and definitions that are based on duration alone can be difficult to apply to recurrent pain. Defining chronic pain solely by pain duration is also contrary to the idea that chronic pain is multi-dimensio- nal in nature. The use of Risk Scores A recent approach has been to define chronic pain prospectively using a risk score to predict the likelihood that clinically significant pain will be present in the future1 . Pain severity is assessed from mul- tiple measures of pain intensity, interference with activities and role disability. This is combined with measurements of three other pro- gnostic variables - depressive sym- ptoms, number of days with pain in the past six months and number of pain sites, to calculate a risk score of 0 – 28. Using this method, pro- bable chronic back pain is defined by a risk score of 22-28 (≥80% pro- bability of significant pain in the fu- ture). Possible chronic back pain is defined by a risk score of 16-21 pre- dicting ≥50% probability of future significant pain. A recent study has compared this prospective approach with a tradi- tional duration-based approach to defining chronic pain in terms of their ability to predict future pain course and outcomes2 . Patients with back pain, headache, or orofa- cial pain were classified on the 0-28 risk score and by Pain Days during the last 6 months alone. Risk score was shown to be a stronger predic- tor of future disability, pain related worry, clinically significant pain, un- employment, and long-term opioid use than Pain Days alone for all three conditions. Back pain is a particularly significant public health problem with approxi- mately 30% of the general popu- lation suffering from lower back pain during any one month3 . It has been estimated that at least 60% of adults experiencing LBP at some time during their life and 6-9% of adults seek healthcare for lower PROGNOSTIC VARIABLES – 0-28 RISK SCORE Risk score value*Item Average pain intensity (0-10 rating) 0 - 2 Worst pain intensity (0-10 rating) 0 - 2 Current pain intensity (0-10 rating) 0 - 2 Interference with usual activities (0-10 rating) 0 - 2 Interference with work/household activities (0-10 rating) 0 - 2 Interference with family/social activities (0-10 rating) 0 - 2 Days of activities limitation due to pain in prior three month 0 - 4 SCL-90-R Depression score 0 - 4 Number of other pain sites 0 - 4 Number of days with index pain in prior six months 0 - 4 Total Risk Score 0 - 28 * Lower risk = 0-15 Possible chronic pain = 16-21 Probable chronic pain = 22-28 Adapted from Von Korff M, Dunn KM. Pain 2008;