Estimation of costs for emergency department and hospital inpatient care in patients with opioid abuse-related diagnoses

The economic burden of prescription opioid abuse is believed to be substantial, however it is not known whether total and per-event hospital (ED and inpatient) costs associated with opioid abuse or misuse differ by insurance status. We also wanted identify predictors of charges. We used the 2006, 2007, and 2008 files of the Healthcare Cost and Utilization Project's Nationwide Emergency Departments Sample (HCUP-NEDS) to identify events and charges assigned opioid abuse, dependence, or poisoning ICD-9-CM diagnosis codes (304.0X, 304.7X, 305.5X, 965.00, 965.02, 965.09). Using methods to account for the sampling design of the NEDS, we estimated national total and mean charges -- overall and by insurance status (Medicare, Medicaid, private insurance, or self-payment). Charges were adjusted using the 2010 Medical Consumer Price Hospital Services index. We used a log-linked gamma regression model to assess potential predictors of charges. The number of opioid abuse-related events was 515,896; 506,837; and 564,559 for 2006, 2007, and 2008, respectively. Approximately 55% visits in each year resulted in inpatient admissions. Total charges billed for opioid abuse-related events were US$9.8; 9.6; and 9.5 billion for 2006, 2007, and 2008, respectively. Medicaid patients had the highest charges in each years followed by Medicare patients. Approximately 93% of total charges were due to subsequent inpatient admission. Overall unadjusted mean charges were $20,651; $20,373; and $18,384 for 2006, 2007, and 2008, respectively. Compared to events paid for by private insurance, Medicaid-covered events had significantly higher mean charges, and self-paid events had significantly lower charges (p < 0.001 for each year). Inpatient admissions resulted in significantly higher mean charges compared to treat-and-release ED visits (p < 0.001 for each year). We found similar results after adjusting for clinical and demographic factors. Age, number of diagnoses, inpatient admission, presence of cardiac tissue disorders, respiratory infections or failure, gastrointestinal hemorrhage, and acute pancreatitis were significantly positively associated with total charges billed (p < 0.001 for all). This study helps in determining differences in hospital costs of opioid abusers by insurance status and in identifying potential predictors of such costs, resulting in better understanding the economic burden of opioid abuse on the healthcare system.