Trends in Hospitalization for Opioid Overdose among Rural Compared to Urban Residents of the United States, 2007-2014
Hospitalizations and deaths due to opioid overdose have increased over the last decades. We used data from the National Inpatient Sample and the American Community Survey to describe trends in hospitalization rates for opioid overdose among rural residents compared with urban residents in the United States from 2007 to 2014. Hospitalization rates for heroin overdose increased in all years and were higher in urban residents compared with rural residents (5.5 per 100,000 in large urban populations vs 2.1 per 100,000 in rural populations in 2014). In contrast, hospitalization rates for prescription opioid overdose were 20% to 30% higher in rural populations compared with large urban populations between 2007 and 2012, before declining in rural populations in 2013 and 2014. The proportion of rural patients admitted for overdose who are cared for in urban hospitals increased from 23.1% in 2007 to 41.2% in 2014. These trends are clinically relevant as rural patients and urban patients may have different discharge needs.
© 2017 Society of Hospital Medicine
Background
Hospitalizations and deaths due to opioid overdose have increased over the last decades, straining the healthcare system and generating substantial costs.1-4Hospitalizations for overdose also represent opportunities to intervene in the opioid epidemic by linking patients to resources for nonpharmacologic chronic pain treatment resources or substance use treatment services during and following hospitalization.5,6Studies of trends in the frequency of hospitalizations for opioid overdose in rural and urban areas are necessary to inform planning and resource allocation for inpatient and postdischarge transitional care.
Nonmedical opioid use and opioid-related deaths and injuries appear to be higher in rural areas.7,8 As well, rural areas tend to be more under-resourced in terms of substance abuse treatment and chronic pain specialty services.9,10 Contemporaneous with rising opioid use has been an increasing trend of rural hospital closures.11 This may compound the impact of opioid-related hospitalizations on remaining rural hospitals and lead to increasing reliance on more distant, urban hospitals to treat and discharge patients with overdoses. Rural residents who are admitted or transferred to urban hospitals may face distinct challenges. Similarly, urban hospitals may struggle during discharge planning to link patients to substance use treatment services in less familiar rural communities.
To better define the differential impact of the opioid epidemic based on patient rurality, we described trends in rates of hospitalization for opioid overdose among rural residents compared with urban residents of the United States. We separated hospitalizations into those due to overdose of prescription opioids, and those related to heroin. Among rural residents who overdosed on opioids, we examined trends in admission to rural versus urban hospitals.
METHODS
Data Source
We analyzed data from the National Inpatient Sample (NIS) from 2007 to 2014, developed by the Healthcare Cost and Utilization Project (HCUP). NIS yields nationally representative estimates of inpatient stays in community hospitals in the United States, regardless of payer. Rehabilitation and long-term care hospital stays are excluded. Prior to 2012, NIS included data on all discharges from a 20% sample of hospitals. Beginning in 2012, NIS included a 20% sample of discharges from all HCUP hospitals. We used weights to estimate trends in the total number of hospital admissions for heroin and prescription opioid overdose (POD) in the US by year, accounting for the change in sampling design in 2012 as recommended by HCUP. Standard errors for estimates accounted for the complex sample design.12 We used data from the US Census American Community Survey on the US population in rural versus urban areas for each year to calculate overdose admission rates per 100,000 residents.
Target Population
Following methods applied in previous analyses of NIS data,1,4,13 we identified hospitalizations for heroin or POD based on International Classification of Diseases 9th Clinical Modification (ICD-9-CM) codes. We use the lay term “overdose” to refer to admissions defined by the medical term “poisoning.” In each year between 2007 and 2013, we determined the total number of admissions due to heroin or prescription opioid by considering ICD-9CM codes 965.00 (poisoning by opium), 965.01 (poisoning by heroin), or 965.09 (poisoning by other opiates and related narcotics); or E code E850.0 (accidental poisoning by heroin); or 850.2 (accidental poisoning by opiates and related narcotics) in any position. We defined admissions for heroin overdose (HOD) as 965.01 or E code of E850.0 in any position, and admissions for POD not related to heroin as 965.00, or 965.09, or E code 850.2 in any position excluding admissions with any heroin-related code 965.01 or E code E850.0 or E935.0 (adverse effects of heroin). We excluded hospitalizations in which a patient was transferred out to another acute care facility to avoid duplicate counting.
Analysis
We classified these admissions based on patient residence in a rural versus urban area. NIS contained a variable representing rural versus urban patient residence based on the county-level framework maintained by the Office of Management and Budget, supplemented with information from Urban Influence Codes developed by the Economic Research Service of the US Department of Agriculture.14 We used this information to create a 3-level variable for patient residence: rural (ie, nonmetropolitan areas with a population less than 50,000), small metropolitan (ie, metropolitan areas with a population of 50,000–999,999), and large metropolitan (ie, metropolitan areas with a population of 1,000,000 or greater). We explored further separating categories (eg, breaking rural into micropolitan population centers and other), but this did not further discriminate admission rates.
