WHEN IS CANCER PAIN MILD, MODERATE OR SEVERE - GRADING PAIN SEVERITY BY ITS INTERFERENCE WITH FUNCTION

As a way of delineating different levels of cancer pain severity, we e xplored the relationship between numerical ratings of pain severity an d ratings of pain's interference with such functions as activity, mood , and sleep. Interference measures were used as critical variables to grade pain severity. We explored the possibility that pain severity co uld be classified into groupings roughly comparable to mild, moderate, and severe. Our hypothesis was that mild, moderate, and severe pain w ould differentially impair cancer patients' function. We were able to identify boundaries among these categories of pain severity in terms o f their interference with function. We also examined the extent to whi ch cancer patients from different language and cultural groups differ in their self-reported interference as a function of pain severity lev el. We found optimal cutpoints that form 3 distinct levels of pain sev erity that can be defined on a 0-10-point numerical scale. We determin ed that, based on the degree of interference with cancer patients' fun ction, ratings of 1-4 correspond to mild pain, 5-6 to moderate pain, a nd 7-10 to severe pain. Our analysis illustrates that the pain severit y-interference relationship is non-linear. These cutpoints were the sa me for each of the national samples in our analysis, although there we re slight differences in the specific interference items affected by p ain. These cutpoints might be useful in clinical evaluation, epidemiol ogy, and clinical trials.