How Definition Affects Emergency Room Encounters for Substance Abuse

Readers of the Jan. 13 Research Corner item might, understandably, have this question: ‘If substance abuse is a problem in emergency rooms, then why do overdoses account for just 0.2 percent of visits?’ The answer is that it depends on how physicians code the diagnosis of individual patient visits. When the definition of addiction is restricted solely to overdoses, it captures only those patients who arrived unresponsive or incoherent. When the definition is expanded to include all addiction and substance abuse visits, those cases account for nearly three times the number of emergency room visits as those identified solely as overdoses. The chart below illustrates what happens when the definition of overdose is expanded to include all substance abuse and addiction diagnoses – the percentage of total visits increases from the 0.22 percent to 0.63 percent. As the number of cases expands, the number of categories of poisoning by ingestion expands. In the case of hospitalized inpatients, the primary agent for substance abuse and overdose is alcohol. The age group most frequently presenting for emergency department treatment of overdose and substance abuse is teenagers. Teens are also most likely to experience an overdose. The majority of the drugs listed in the chart below are prescription medications that can be abused or misused. However, illicit drugs (such as cocaine, heroin, cannabis, and hallucinogens) rank among the top 10 causes of poisonings. This analysis is based on information from the All Payer Claims Database, which includes Medicaid patients, and roughly 65 percent of commercially-insured patients. Because the database does not include the uninsured and those covered under the traditional Medicare program (not Medicare Advantage), it may underestimate the number of cases linked to substance abuse and overdoses. (1/27)