Assessing global pain severity by self-report

Research on pain measurement reviewed supports the following conclusions about assessing global pain severity by self-report in clinical and health services research: 1) Key aspects of pain to be measured are its intensity, its interference with activities (or disability) related to pain, and its persistence (chronicity). 2) Pain intensity and pain-related interference with activities, while conceptually distinct, are often highly correlated. In some circumstances, pain intensity and interference with activities define an underlying dimension of global pain severity, which reflects both subjective pain experience and the impact of pain on functioning. 3) Chronicity has not been consistently found to be highly correlated with pain severity. Pain severity and chronicity should be regarded as distinct dimensions. However, measurement of persistence or chronicity has received only limited attention. Measuring chronicity by the number of pain days in a 6-month or 1-year period is recommended at the present time. 4) Recall of average pain intensity, interference with activities, and persistence over periods of at least 3 months shows high correlation with summary measures from daily diary data. Summary measures of pain status based on patient recall may be considered valid. 5) While many approaches to assessing pain intensity are reliable and valid, verbal and numerical rating scales have advantages for health services research and many clinical applications. 6) There are many reliable and valid approaches to measuring interference with activities due to pain, but there is no clear preference among the alternatives. 7) The SF-36 Bodily Pain scale is a reliable and valid two-item measure of global pain severity that is not site-specific. The Graded Chronic Pain Scale provides a method of assessing global pain severity that is site specific. These scales are highly correlated with each other, and their properties are consistent with the preceding observations. Measures of global pain severity should be supplemented by an item assessing pain persistence (eg, days with pain in the prior 6 months or 1 year).