Do psychological and behavioral factors classified by the West Haven-Yale Multidimensional Pain Inventory (Swedish version) predict the early clinical course of low back pain in patients receiving chiropractic care?

BACKGROUND To investigate if psychological and behavioral factors (as determined by the Swedish version of the West Haven-Yale Multidimensional Pain Inventory, MPI-S) can predict the early clinical course of Low Back Pain (LBP). METHODS MPI-S data from patients (18-65 years of age) seeking chiropractic care for recurrent and persistent LBP were collected at the 1(st) visit. A follow-up questionnaire was administered at the 4(th) visit. The predictive value of the MPI-S subgroups Adaptive Copers (AC), Interpersonally Distressed (ID) and Dysfunctional (DYS) was calculated against the subjective improvement at the 4(th) visit and clinically relevant difference in pain intensity between the 1(st) and 4(th) visit. RESULTS Of the 666 subjects who were included at the 1(st) visit, 329 completed the questionnaire at the 4(th) visit. A total of 64.7 % (AC), 68.0 % (ID) and 71.3 % (DYS) reported a definite improvement. The chance of "definite improvement", expressed as relative risk (95 % CI) with the AC group as reference, was 1.05 (.87-1.27) for the ID and 1.10 (.93-1.31) for the DYS groups, respectively. The DYS and ID groups reported higher values in pain intensity both at the 1(st) and the 4(th) visit. The proportion of subjects who reported an improvement in pain intensity of 30 % or more (clinically relevant) were 63.5 % AC, 72.0 % ID and 63.2 % DYS. Expressed as relative risk (95 % CI) with the AC group as reference, this corresponded to 1.26 (.91-1.76) for the ID and 1.09 (.78-1.51) for the DYS groups, respectively. CONCLUSIONS The MPI-S instrument could not predict the early clinical course of recurrent and persistent LBP in this sample of chiropractic patients. TRIAL REGISTRATION Clinical trials.gov; NCT01539863 , February 22, 2012.