Bodily pain and vitality are the key factors in the disability of chronic low back pain patients under Short Form 36 base study: a five-year cohort study

Abstract Background Chronic low back pain (CLBP), a significant cause of disability, is expected to increase with aging. Short Form 36 (SF-36) indicated higher baseline component scores predict CLBP disability at shorter follow-ups, with unexplored five-year associations. The study aimed to test the associations of the physical and mental subscales of the SF-36 at baseline with disability at the five-year follow-up point among patients with CLBP. Methods Patients aged between 20 and 65 years with CLBP were enrolled at baseline and followed at the five-year point. The Oswestry Disability Index (ODI), the physical functioning (PF) subscale of the SF-36, and self-reported total months of disability (TMOD) over the past five years were used as the indices of disability. The four physical and mental subscales of the SF-36 were used as independent factors, respectively. Multiple linear regression was used to compare the associations of the physical and mental subscales at baseline with disability at follow-up. Results Two hundred twenty-five patients with CLBP were enrolled at baseline and 111 participated in followed at the five-year point. Among the SF-36 subscales, the scores of bodily pain (BP), vitality (VT), and social functioning (SocF) at baseline were significantly correlated with the three indices of disability at follow-up. After controlling for demographic and clinical variables, BP and VT at baseline were most strongly associated with the ODI and TMOD at follow-up among the four physical and mental subscales, respectively. PF at baseline was most strongly associated with itself at follow-up among the four physical subscales. Conclusion Our results demonstrated that both the physical and mental subscales of the SF-36 at baseline could predict disability at the five-year follow-up point among patients with CLBP. The BP and VT subscales were independent factors associated with disability among the physical and mental subscales, respectively.