Pain Scores not Always Accurate in Studies

Perceived pain can be affected by distractions and mood, which should be taken into consideration when measuring pain scores in research, according to a paper in the International Journal of Behavioural and Healthcare Research.

There are many chronic illnesses and injuries that have no well-defined symptoms other than pain, but because of the subjectivity in a patient's reporting of their experience of the illness or injury, healthcare workers have difficulty in addressing the patient's needs. When subjective reporting of pain is a critical component of a clinical trial, researchers involved in the trial often find it difficult to determine efficacy from patient to patient based on the subject's own evaluation of painful symptoms. Commonly, patients are asked to rate their pain on a 0 to 10 scale, where 0 represents no pain whatsoever and a value of 10 indicates excruciating pain. However, one person's "8" may be another's "10" on the same scale.

When assessing the effectiveness of an intervention it is common practice that patients whose post-treatment pain scores are lower than their pre-treatment scores are categorized as having undergone effective treatment. However, this assumption may ignore the subjectivity of their experience of pain, where the simple act of being "treated" may lower their perception of their pain without the underlying cause of the pain having been physically reduced.

Now, Sean Murphy, of Washington State University, in Spokane, Washington, USA, and colleagues have borrowed economics theory to compare the conventional binary "pain no-pain" measure of treatment success commonly used in practice and in clinical trials. The researchers are using the theory as a new approach to modeling pain that allows for more "fuzzy" reporting of pain by precluding certain aspects of bias. The team investigated how common misclassification is and how it can influence outcomes.

The study is titled, “A cautionary note on the use of perceived pain scores in health outcomes research.” Their findings suggest that the chance that a typical patient misclassifies their perceived pain ranges from about 3% (for patients who mistakenly think they do not improve, but actually do) to about 14% (for patients who think they improve, but actually do not improve). As such, health outcomes researchers, practitioners and policy makers must use caution when relying solely on self-reported pain reductions as a gauge of therapy effectiveness. The team points out that their exploratory research requires follow-up work to further confirm the findings.

Source: Inderscience Publishers--Have you considered this as a potential problem in the past? Leave a comment.