Psychometric evaluation of multidimensional pain inventory (Swedish version) in a sample of elderly people.

Objectives The aim was to psychometrically evaluate the Swedish version of the Multidimensional Pain Inventory (MPI-S) and the “brief screening version of MPI-S” for use in an elderly sample. Methods This study comprised 175 people aged 76–99 years reporting pain and in need of help to manage daily living. The instrument’s factor structures were investigated through factor analyses, convergent and discriminant validity were assessed through inter-scale correlations and correlations with items from SF-12. Reliability was assessed by Cronbach’s alpha. Results The full-length version of MPI-S did not, in general, show any satisfactory validity and reliability when used among elderly. It had acceptable convergent and discriminant validity, but the factor analysis did not show a good model fit. Low α values were found for most of the sub-scales. However, the brief screening version of MPI showed acceptable validity and reliability, except for rather low α values in sections 3 and 4. Conclusion The MPI-S instrument may not be very useful for measuring pain among frail elderly. The brief screening version may instead be a better alternative to the full version of the MPI-S. However, the small number of observations may be the reason to the lack of fit, and further studies are warranted