Abstract/free full access: Comparison of numerical and verbal rating scales to measure pain exacerbations in patients with chronic cancer pain

Background
Numerical rating scales (NRS), and verbal rating scales (VRS) showed to be reliable and valid tools for subjective cancer pain measurement, but no one of them consistently proved to be superior to the other. Aim of the present study is to compare NRS and VRS performance in assessing breakthrough or episodic pain (BP-EP) exacerbations.

Results
NRS revealed higher discriminatory capability than VRS in distinguishing between background and peak pain intensity with a lower proportion of patients giving inconsistent evaluations (14% vs. 25%). NRS also showed higher reproducibility when measuring pain exacerbations (Cohen's K of 0.86 for NRS vs. 0.53 for VRS) while the reproducibility of the two scales in evaluating background pain was similar (Cohen's K of 0.80 vs. 0.77). Conclusions Our results suggest that, in the measurement of cancer pain exacerbations, patients use NRS more appropriately than VRS and as such NRS should be preferred to VRS in this patient's population.