Treatment Effects of Opioids Versus NSAIDs Prescribed from the Emergency Department Following Motor Vehicle Crash: A Propensity Matched Analysis
*Francesca L Beaudoin, Brown University
Keywords: propensity scores, causal inference, treatment effects, pain
Millions of Americans present to the emergency department (ED) after a motor vehicle collision. Acute musculoskeletal pain is a common consequence, and patients are often discharged with prescriptions for oral opioids or nonsteroidal anti-inflammatory drugs (NSAIDs). It is unknown how early pain management may influence the pain trajectory after the ED visit. We evaluated the effect of opioids vs. NSAIDs initiated from the ED on pain outcomes at six weeks using data from a large cohort of adult European Americans. We estimated the treatment effect of opioids versus NSAIDs by imputing the unobserved potential outcomes using splines along the propensity score and linear adjustments for orthogonal directions. This method adjusts for possible covariate imbalances between the two treatment groups. Propensity scores were calculated iteratively using logistic regression until balance on all the covariates within strata of propensity-score subclasses was achieved. Missing data were handled using multiple imputation. Individuals outside the region of common support were truncated. This methodology allows observational studies to be treated like randomized controlled trials.