Psychometric testing of the brief screening version of Multidimensional Pain Inventory (Swedish version).

Background: The brief screening version of the Multidimensional Pain inventory (MPI) is a shorter version of the West Haven-Yale Multidimensional Pain Inventory that measures pain in a multidimensional way and is theoretically linked to a cognitive-behavioural perspective on chronic pain.
Objectives: The aim of this study was to psychometrically evaluate the 'brief screening version' of the Multidimensional Pain inventory Swedish version (MPI-S).
Methods: An age-stratified cross-sectional study, comprising 384 people aged 18-102 years, was carried out in southern Sweden in 2005. Factor analyses were performed to investigate the factor structure of the instrument and inter-correlation between the sub-scales as well as external measures were used to assess convergent and discriminant validity. Reliability was assessed by internal consistency (Cronbach's alpha).
Results: Mean scores and standard deviations are presented for the total sample as well as for each stratum. The inter-correlations revealed that discriminant validity was not satisfactory in the total sample, although the correlation analysis in each stratum showed acceptable discriminant validity in most age groups. The factor structure was the same as in the MPI-S in all age groups, except for those aged >or=90 years. Reliability tests (Cronbach's alpha) showed alpha values ranging between 0.68 and 0.93.
Conclusion: The result showed that the instrument had acceptable validity and reliability in all age groups except for those aged >or=90 years. Thus, the instrument can be seen as a useful (multidimensional) form of screening for chronic pain.