Are responses to two pain questionnaires related differently to the SF36 mental and physical scores in military personnel during rehabilitation following trans-tibial amputation?

Military members with a war-related trans-tibial amputation experience pain and loss of physical capabilities associated with the amputation. The relationship between pain and self-perceived mental and physical wellbeing has not been studied in relationship to their rehabilitation

44 service members with combat-related traumatic unilateral trans-tibial amputation participated in 12-week randomized trial comparing standard military rehabilitation with standard plus quadriceps neuromuscular electrical stimulation.   Subjects were assessed for pain and completed the SF36 questionnaire on weeks 0, 7 and 12. Pain assessment included the McGill Pain Questionnaire and Brief Pain Inventory(BPI). The McGill presented pain intensity and pain rating index quantified the severity of the pain. The BPI pain severity and pain interference assessed pain severity and pain interference in activities.

The SF36 mental composite score showed a strong negative association with the BPI influence scale (p=0.0001). The SF36 physical composite score was strongly negatively associated with all scales (McGill pain-now p=0.0003, McGill total count p=0.004, BPI severity p<0.0001, BPI inference p=0.002). Only BPI inference was strongly negatively related to SF36 Mental composite (p=0.0004), and BPI severity negatively trended for the SF36 Physical composite (p=0.07). Bayesian Model Averaging, noted 100% probability that the BPI inference had an association with the Mental composite and 67% probability that the BPI severity had an association the Physical composite. Multivariate Bayesian regression noted 100% probability that the BPI inference was negatively related to the SF36 Mental and 97% probability that the BPI severity was negatively related to the SF36 Physical.

In these servicemen, negative associations were observed between self-perceived pain during daily activities and mental wellbeing and between pain severity and self-perceived physical wellbeing.