One-year follow-up of first onset low back pain.

Efforts to examine the process and risk of developing chronic back pain have relied generally upon retrospective study of individuals with already established pain. In an alternative approach to understanding the clinical course and evolution of low back disorders, a cohort of 76 men experiencing their first episode of back pain was assessed prospectively at 2, 6 and 12 months following pain onset. Standard measures of pain (Descriptor Differential Scale: DDS), disability (Sickness Impact Profile: SIP), and distress (Beck Depression Inventory: BDI) were employed to classify the sample into five groups: Resolved, Pain Only, Disability/Distress Only, Pain and Mild Disability/Distress, and Clinical Range. At both 6 and 12 months post pain onset, most (78%, 72% respectively) of the sample continued to experience pain. Many also experienced marked disability at 6 months (26%) and 12 months (14%). At 12 months, no participants had worsened relative to the 2-month baseline. Doubly multivariate analyses of variance (MANOVAs) were employed to compare baseline groups (Pain Only, Pain and Mild Disability/Distress, Clinical Range) on the DDS, SIP, and BDI across time. The group by time interaction from 2 through 12 months was reliable, with greatest change occurring in the Clinical Range group in disability and distress; interestingly, the decrease in pain was comparable among all groups. Follow-up tests across measures demonstrated greater change in the early (2-6-month) interval and relative stability in the later (6-12-month) interval. Comparison of those classified as 'improvers' with those who did not improve from 2 to 12 months showed similar findings. The clinical course of first onset back pain may be prolonged for many patients, and involves a continuum of related disability and distress. Individuals at risk for marked symptoms 1 year after an initial episode of back pain can be identified early, and prompt treatment might reduce the risk of pain chronicity.