(O-L1) Substance Use Disorder and Overutilization of Emergency Departments

Objectives: This paper seeks to determine the association between substance use and excess emergency department visits, while examining characteristics of our sample population, such as: racial and age groups, insurance types, and mortality rates.

Background: In 2008, for the first time in more than three decades, the number of poisoning deaths surpassed the number of deaths due to motor vehicle accidents.1 From 2006 to 2011, the total number of emergency department (ED) visits increased by nearly five percent.2 This was the second largest increase and an important contributor to the skyrocketing cost of healthcare.2 With the Medicaid expansion under the Affordable Care Act, ED visits have increased even more, thus making it very important to understand the association between rising levels of ED visits and the healthcare costs of opioid use.3

Methods: We analyzed the California State Emergency Department Database (SEDD), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, which contains discharge information on all outpatient ED visits.8 We included 2006-2009 and 2011 data which contained 46,132,211 ED visit records to find out the trend. Then analyzed 2011 data to find out the association of substance use and ED visits. Substance use and its subcategories were detected based on relevant International Classification of Diseases (ICD-9) codes. We utilized tabular and then multivariable analysis methods to find out the association between substance use and excess ED visit, controlling for demographic risk factors. In multivariable analysis, data was considered clustered at the level of patients and the standard errors estimation was adjusted accordingly. Prevalence ratios are presented as point estimates ± Standard Deviation, and mortality ratios as point estimates (95% Confidence Intervals). A p-value < 0.05 was considered statistically significant. Data was analyzed by using STATA 14.2 SE software (StataCorp LLC, College Station, TX).

Results: In the study period, the prevalence of substance use increased from 2006 to 2011 (p < 0.001) (Figure 1). The prevalence of opioid use was 28.51 ±23.15, and prevalence of non-opioid substance use was 59.61 ±53.76 per 1000 ED visits. Non-opioid substance use was more common than opioid use in patients aged up to 50 years (p < 0.001) (Figure 2).

Mortality decreased from 2006 (2.05 per 1000 ED visits) to 2011 (1.62 per 1000 ED visits), while patients with opioid use had higher mortality ratio (2.02 per 1000 ED visits) as compared to those with no history (1.79 per 1000 ED visits) (p = 0.047). In 2011, opioid use was most common in Native Americans (p < 0.001), followed by Caucasians (p < 0.001). Opioid use was associated with increased emergency department visits (p < 0.001) (Table 1) after controlling for sex, age, race, type of insurance, and number of chronic diseases.

Conclusions: With the growing opioid epidemic, our study highlights the impact of opioid and non-opioid substance use on ED utilization. We found an increase in substance use prevalence and an increase in utilization of ED resources, especially for opioid users as compared to non-opioid substance users. As the ED is one of the main resources for substance users, it is important to find avenues to provide affordable and accessible healthcare for these patients. Lastly, it is crucial to implement harm reduction principles and establish outpatient care to ensure the patient’s health, and ultimately, form durable solutions to address the opioid epidemic.

References (Optional): 1. Warner M, Chen LH, Makuc DM, Anderson RN, Miniño AM. Drug poisoning deaths in the United States, 1980–2008. NCHS data brief, no 81. Hyattsville, MD: National Center for Health Statistics. 2011.W
2. Skinner H (Truven Health Analytics), Blanchard J (RAND), Elixhauser A (AHRQ). Trends in Emergency Department Visits, 2006-2011. HCUP Statistical Brief #179. September 2014. Agency for Healthcare Research and Quality, Rockville, MD. https://www.hcup-us.ahrq.gov/reports/statbriefs/sb179-EmergencyDepartment-Trends.pdf
3. Nikpay, Sayeh, et al. “Effect of the Affordable Care Act Medicaid Expansion on Emergency Department Visits: Evidence From State-Level Emergency Department Databases.” Annals of Emergency Medicine, vol. 70, no. 2, 2017, doi:10.1016/j.annemergmed.2017.03.023.

Funding (Optional): N/A