The variation of opioid prescription after injury and its association with long-term chronic pain: A multicenter cohort study.

Background: Opioid overprescription in trauma contributes to the opioid epidemic through diversion of unused pills. Through our study, we sought to do the following: (1) understand the variation in opioid prescription after injury and its relationship to patient and/or clinical variables, and (2) study the relationship between opioid prescribing and long-term pain and analgesic use.

Method: Trauma patients with an injury severity score ≥9 admitted to 3 level 1 trauma centers were screened for chronic pain and analgesic use 6 to 12 months postinjury. First, multivariable linear regression models were constructed with "oral morphine equivalents" and "number of opioid pills prescribed" at discharge as dependent variables. The coefficients of determination were calculated to determine how much of the variation in opioid prescription was explained by patient and clinical variables. Second, a multivariable logistic regression analysis was created to study the association between opioid prescription at discharge and chronic pain/analgesic use at 6 to 12 months. Analyses were adjusted for patient demographics, socioeconomics, comorbidities, injury parameters, and hospital course.

Results: Of the 2,702 patients included (mean [standard deviation] age: 61.0 [21.5]; 55% males), 74% were prescribed opioids at discharge (mean number of pills [standard deviation]: 24.0 [26.5]; mean oral morphine equivalent [standard deviation]: 204.8 [348.1]). The adjusted coefficients of determination for oral morphine equivalents and number of pills was 0.12 and 0.21, respectively, suggesting that the measured patient and clinical factors explain <21% of the variation in opioid prescribing in trauma. Patients prescribed opioids were more likely to have chronic pain (odds ratio [95%] confidence interval: 1.34 [1.05-1.71]) and use analgesics daily (odds ratio [95%] confidence interval: 1.86 [1.25-2.77]) 6 to 12 months postinjury.

Conclusion: The variation in opioid prescription after traumatic injury is more affected by system and provider level rather than clinical or patient-related factors, and opioid prescribing correlates independently with long-term chronic pain and continued analgesic use postinjury. Efforts to decrease opioid use should prioritize standardizing prescription practices after traumatic injury.