Development and Validation of a Risk Score to Identify Patients at High Risk for Opioid-Related Adverse Drug Events

BACKGROUND: Opioid-related adverse drug events (ORADEs) are common causes of hospitalization and increased health care costs. OBJECTIVES: To (a) estimate rates of specific adverse drug events (ADEs) among gastrointestinal (GI) surgery patients receiving postoperative opioids; (b) examine the utility of a risk-scoring model in categorizing patients at high risk of experiencing ORADEs; and (c) quantify potential clinical/economic benefits of targeting high-risk GI surgical patients for opioid-sparing regimens in terms of hospitalization cost, length of stay (LOS), and 30-day readmission rates. METHODS: Using a retrospective design based on an administrative database, patients with an inpatient surgical procedure between January 1, 2010, and December 31, 2010, were included. GI surgical patients aged greater than 18 years followed from admission through 30 days postdischarge were characterized as high or low risk using clinical/demographic characteristics and were evaluated for several outcomes. Using multivariate logistic regression, the ORADE incidence, total hospitalization cost, LOS, and 30-day readmissions were compared for high-risk and low-risk patients. RESULTS: In 87.8% (n = 3,235) of the surgical population, there was a strong concordance between risk assignment and ORADE incidence. Among the remaining 12.2% (n = 449) of patients, 5.5% (n = 202) were low risk with an ORADE, and 6.7% (n = 247) were high risk without an ORADE. Overall, 20.6% (n = 344) of high-risk patients experienced ≥ 1 ORADE (mean cost: $31,988; LOS: 12.1 days) compared with only 5.3% (n = 107) of low-risk patients (mean cost: $25,216; LOS: 8.0 days). High-risk patients had higher hospitalization costs and longer LOS than low-risk patients, respectively (mean cost: $19,234 vs. $13,036; mean LOS: 6.8 days vs. 3.3 days). These differences correspond to 47.0% higher costs for high-risk patients and an LOS approximately twice as long compared with low-risk patients. CONCLUSIONS: Patient clinical/demographic characteristics influence the risk of developing ORADEs. Risk assessment tools can effectively identify high-risk patients, thereby enabling interventions that can reduce ORADEs, decrease hospital costs, and improve postsurgical experiences for patients.