Pain assessment tools: is the content appropriate for use in palliative care?

Inadequate pain assessment prevents optimal treatment in palliative care. The content of pain assessment tools might limit their usefulness for proper pain assessment, but data on the content validity of the tools are scarce. The objective of this study was to examine the content of the existing pain assessment tools, and to evaluate the appropriateness of different dimensions and items for pain assessment in palliative care. A systematic search was performed to find pain assessment tools for patients with advanced cancer who were receiving palliative care. An ad hoc search with broader search criteria supplemented the systematic search. The items of the identified tools were allocated to appropriate dimensions. This was reviewed by an international panel of experts, who also evaluated the relevance of the different dimensions for pain assessment in palliative care. The systematic literature search generated 16 assessment tools while the ad hoc search generated 64. Ten pain dimensions containing 1,011 pain items were identified by the experts. The experts ranked intensity, temporal pattern, treatment and exacerbating/relieving factors, location, and interference with health-related quality of life as the most important dimensions. None of the assessment tools covered these dimensions satisfactorily. Most items were related to interference (231) and intensity (138). Temporal pattern (which includes breakthrough pain), ranked as the second most important dimension, was covered by 29 items only. Many tools include dimensions and items of limited relevance for patients with advanced cancer. This might reduce compliance and threaten the validity of the assessment. New tools should reflect the clinical relevance of different dimensions and be user-friendly.