March 25, 2008 — Patients who have sustained a traumatic injury continued to have moderately severe pain 1 year after the injury, suggesting that better pain interventions are needed, according to the results of a study reported in the March issue of the Archives of Surgery.

"Recent studies with long-term follow-up of trauma revealed that 5 to 7 years after injury, chronic pain was present in most patients who sustained pelvic fractures and serious lower extremity injuries," write Frederick P. Rivara, MD, MPH, from the University of Washington in Seattle, and colleagues. "Pain was an important contributor to disability in these patients and often interacted with other sequelae of trauma, such as posttraumatic stress disorder and depression, to affect functional recovery."

This study aimed to determine the prevalence of pain in a large cohort of trauma patients 1 year after injury as well as to identify personal, injury-related, and treatment factors predicting the presence of chronic pain in these patients.

At 69 hospitals in 14 US states, 3047 patients (10,371 weighted) aged 18 to 84 years were hospitalized for acute traumatic injuries and survived to 12 months after the injuries. The primary endpoint was pain 12 months after injury, measured with the Chronic Pain Grade Scale.

At 12 months after injury, 62.7% of patients reported injury-related pain, and most of these reported pain in more than 1 body region. On a 10-point scale, the mean severity of pain in the last month was
5.5 ± 4.8. Reported pain varied with age and was more frequent in women and in those with untreated depression preceding the injury.

The presence of pain at 3 months predicted both the presence and degree of severity of pain at 12 months. Patients with a college education and those with no previous functional limitations tended to report lower pain severity.

"Most trauma patients have moderately severe pain from their injuries 1 year later," the study authors write. "Earlier and more intensive interventions to treat pain in trauma patients may be needed."

Limitations of the study include inability to evaluate the adequacy of in-hospital pain control as a factor that might affect long-term prevalence or severity of pain, inability to evaluate the use of pain control service consultants among study patients, and retrospective recall of intensity and persistence of pain.

"The findings of this study suggest that interventions to decrease chronic pain in trauma patients are needed," the study authors conclude. "The high prevalence of pain, its severity, and its effect on functioning warrant such interventions. This may consist of interventions during the acute phase of hospitalization to aggressively treat early pain and better manage neuropathic pain."

The National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, and the National Institute on Aging, National Institutes of Health funded this study. Three of the study authors have obtained funding. The other study authors have disclosed no relevant financial relationships.

Arch Surg. 2008;143:282-287.

Clinical Context

Study Highlights

• Data were collected as part of the National Study on the Costs and Outcomes of Trauma, a prospective cohort study of patients treated at 18 trauma and 51 nontrauma centers in 14 US states.
• Included were patients aged 18 to 84 years at the time of injury with at least 1 injury that had an Abbreviated Injury Scale score of 3 or higher.
• Excluded were patients with burns and hip fractures, those who delayed care for more than 24 hours, or those who spoke no English or Spanish.
• Patients were sampled from discharge lists at study hospitals to obtain a prespecified number of patients by age, Injury Severity Scale score, and principal body area affected.
• At 3 months after the injury, 60.7% of the cohort was interviewed.
• Of those alive at 12 months, 82% (3047) completed a follow-up interview at 12 months in addition to the interview at 3 months after injury.
• At the 12-month interview, patients were asked about pain in the previous 4 weeks with questions from the Chronic Pain Grade Scale, which assessed the presence of pain in any of 7 body areas.
• The 7 body areas were the back, neck, head, abdomen, joints, chest, and face.
• Patients were asked to rate the pain level and the average pain intensity on a scale of 0 (no pain) to 10 (worst possible pain).
• The 36-Item Short-Form Health Survey was used to assess the impact of pain on activities.
• Injury variables examined included demographics, preinjury health, and injury factors such as location of injury and the need for surgery or assisted ventilation.
• Multiple linear regression analysis was used to examine predictors of injury-related severity of pain, representing 10,371 weighted patients.
• At 12 months after injury, 62.7% (two thirds) of patients reported pain related to their injury.
• Prevalence of pain was similar among men and women, was most common in those aged 35 to 44 years, and was least common among those aged 75 to 84 years.
• Mean severity of pain within the past 4 weeks was similar in men and women and in patients of different ages but higher in non-Hispanic nonwhite patients and lowest in non-Hispanic white patients.
• The most common painful areas were the joints and extremities (44.3%), back (26.2%), and the head (11.5%) and neck (6.9%).
• Only 37.3% of participants had pain in 1 body area, and 59.3% had pain in 3 or more body areas with a mean of 2.2 painful body areas.
• Average severity of pain was higher in those with more affected body areas, from a mean of 4.5 for 1 painful area to 8.5 for 6 painful areas.
• The mean severity of pain was 5.5 of 10.
• Pain was more common among those who were poor and were smokers and intravenous drug users before injury and in those with baseline depression who did not take medication.
• Prevalence was not related to sex, alcohol intake, preinjury, or race.
• Pain was more common with lower extremity injuries and more severe injuries and least common with head injuries.
• Pain was more common in those with more injury sites, who were treated at a trauma center, and who underwent surgery or were ventilated.
• Predictors of pain at 12 months included female sex, untreated depression before injury, care in a trauma center, admission to an intensive care unit, surgery for traumatic injury, and the presence of pain at 3 months.
• Predictors of severity of pain at 12 months included lower educational level, smoking, intravenous drug use before injury, poor health or functional status before injury, multiple injuries, a penetrating traumatic injury, trauma center care, and receipt of ventilation.

Pearls for Practice

• Two thirds of patients who survive traumatic injury have persistent injury-related pain at 12 months, and most have pain in more than 1 body area.
• Predictors of pain and severity of pain after injury include younger age, female sex, untreated depression before injury, care in a trauma center, admission to an intensive care unit, surgery for traumatic injury, and the presence of pain at 3 months after injury.

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