A consecutive sample of 53 chronic
cancer pain patients were administered 5 different
pain intensity scales: a visual analogue scale (
VAS), a numerical rating scale from 0 to 10 (NRS), a verbal rating scale (VRS), the Italian
Pain Questionnaire (Italian version of the McGill
Pain Questionnaire) (PRI), and the Integrated
Pain Score (IPS) which is an instrument designed at the
Pain Therapy and
Palliative Care Division of the National Cancer Institute of Milan to integrate
pain intensity and duration in a single measure. These scales were administered before and after a definite
therapy change. At the time of the second evaluation the patients were also administered a
pain relief scale (IRS).
A factor analysis of the scoring properties of these instruments revealed a high degree of association between the variables. A single factor clearly emerged explaining most of the different scales variability. A logistic regression analysis showed that VAS, NRS, VRS were more strongly associated with IRS than PRI and IPS.