Predictors of pain 12 months after serious injury

The majority of patients will report pain 12 months after a serious injury. Determining the independent risk factors for pain after serious injury will establish the degree to which high-risk patients can be detected in the acute setting and the viability of early triage to specialist pain services.

A prospective cohort study of patients following serious injury was conducted. The initial assessment comprised a comprehensive battery of known and possible risk factors for persistent pain. Patients were assessed at 12 months for pain severity and for the presence of chronic pain.

Two hundred ninety patients underwent an initial assessment of whom 238 (82%) were followed up at 12 months. At 12 months, 171 (72%) patients reported some pain over the past 24 hours. Thirty-five patients (14.7%) reported chronic pain. Five factors independently predicted the 24-hour pain severity: preinjury physical role function, preinjury employment status, initial 24 hours pain score, higher beliefs in the need for medication, and compensable injury (R(2) = 0.21, P < 0.0001). Four factors predicted the presence of chronic pain at 12 months: not working prior to injury, total Abbreviated Injury Scale, initial pain severity, and initial pain control attitudes (pseudo R(2) = 0.24, P = 0.0001).

Factors present at the time of injury can allocate patients into high- or low-risk groups. The majority of cases of chronic pain emerging from the high-risk group warrant more intense clinical attention. We recommend recording these factors in discharge documentation as indicators of persistent pain.