Relationship between MPQ and VAS in 962 patients. A rationale for their use

1) To analyse the information provided both by the Visual Analogue Scale (VAS) and by the McGill Pain Questionnaire (MPQ) in a cross-sectional study with patients affected by different kinds of pain and to study the relationship between VAS and MPQ scores in the same patient sample.

962 patients affected by different kinds of pain (i.e. neuropathic pain, acute post-traumatic pain, chronic musculo-skeletal pain, headache, and cancer pain) were enrolled into the study during the first visit for pain management. The horizontal 10cm VAS and the Italian version of the MPQ were administered.

VAS scores proved to be significantly lower in acute post traumatic and in chronic musculo- skeletal pain compared to headache and neuropathic pain. VAS scores were signi- ficantly higher in neuropathic pain compared to cancer pain. MPQ total score (Pain Rating Index, PRI) related to neuropathic pain was significantly higher than scores reported in the other pain groups, with the exception of cancer pain. Cancer pain MPQ total score was higher than acute post-traumatic and chronic musculo-skeletal PRI pain scores. Different patterns of MPQ dimensions emerged within each pain group. The association between VAS and PRI, analysed by means of stepwise multiple regression analyses was significantly different among the groups (p<0.0001). The percentage of VAS variance explained by MPQ PRI score ranged from 6% (headache) to 32% (neuro-pathic pain).

Several differences emerged among the pain groups. VAS and MPQ resulted to address pain aspects only partially overlapping. In some clinical conditions (headache and cancer) the MPQ can provide more detailed and clinically useful information about patients' pain experience.