Enhancing Identification of Opioid-Involved Health Outcomes Using Linked Hospital Care and Mortality Data

STATUS: Completed Project

BACKGROUND

National-level statistics on opioid-related hospitalizations are limited and often incomplete. Electronic health records (EHR) contain much more detailed data such as clinical notes and laboratory results, which allow for a wider perspective on hospitalization. These combined data will allow health policymakers, clinicians, and researchers to develop effective prevention strategies and improve patient care. The National Center for Health Statistics (NCHS) houses three data sources that, when combined, will offer broad, national-level data on hospital care and death related to opioid-involved drug overdose. The first source, the National Hospital Care Survey (NHCS), attempts to collect inpatient, emergency department, and outpatient claims and EHR data from a sample of approximately 600 hospitals. The second source is the National Death Index (NDI), which includes all deaths occurring within the U.S. along with the cause of death. The third source, The National Vital Statistics System restricted-use Drug-Involved Mortality files (DIM) on drug overdose death includes information on specific drugs involved in overdose death. Each of these three sources has limitations, such as the identification of specific opioids and the inclusion of deaths occurring outside of hospital settings. The combination of these data sources will allow researchers to follow patients with an opioid event from presentation at a hospital to death (if applicable) and retroactively analyze previous hospital encounters for patients who died of an opioid overdose

PURPOSE

This project aimed to improve surveillance and expand researchers’ access to data on hospital care patterns and risk factors associated with opioid overdose deaths by:

• Creating a dataset for research by linking hospital care and mortality data by merging the NHCS, NDI, and DIM and analyzing this dataset to explore characteristics of individuals who had opioid-related events, patterns of hospital use in months before death, and comparisons of patients and services.
• Improving researchers’ ability to identify opioid-specific hospital encounters and deaths by enhancing existing techniques and developing new methods in vocabulary and procedure coding.
• Enriching the opioid-specific hospital care data available in the linked NHCS, NDI, and DIM datasets with enhanced hospital and death certificate opioid identification.
• Investing in the infrastructure to improve the collection and reporting of hospital data as well as disseminate the methodologies, analyses, and knowledge obtained.

KEY IMPACTS

Addressing national priorities for health: Linked datasets to study the opioid overdose crisis
The linked NHCS, NDI, and DIM datasets provide data on the specific drugs involved in overdose deaths for patients who utilized a hospital for treatment before their death. Through the linked dataset, this project allows researchers to compare the characteristics of patients who experienced an opioid-related hospitalization and identify patterns of hospital use for patients who died of an opioid overdose.

Enhancing analytical resources: Enhanced opioid-identification algorithm
The project team developed the algorithm to identify opioid-involvement and overdose encounters in unstructured clinical notes that otherwise would not have been identified using medical codes alone, thus highlighting the advantage of collecting EHR data as part of the NHCS. The algorithm was also used to inform the development of another algorithm for identifying opioid involvement with co-occurring substance use disorders and mental health issues, thus improving the variables available to study morbidity and mortality for patients with these co-occurring disorders.

Improving the access and use of data: NHCS Annual Hospital Report portal
The project team built the NHCS Annual Hospital Report secure web-based portal, which allows participating hospitals that submit 12 months of NHCS data to produce customizable reports on hospital encounters. Participating hospitals have access to a patient mortality report for their hospital that presents results from the linked NHCS and NDI data.

PUBLICATIONS

Linked Datasets and Data Dictionaries: NHCS, NDI, and DIM. Linked data files are available through the CDC Research Data Center. Data dictionaries on mortality variables as well as death certificate and NDI match variables are publicly accessible.

2014 NHCS Data Linked to the 2014-2015 NDI Linked to the 2014-2015 DIM Data Report. This report describes the three source datasets and provides additional resources on the linkage. The linked data file contains over 5,000 NHCS records in which the cause of death involved an opioid.

The Linkage of the 2014 NHCS to the 2014/2015 NDI: Methodology Overview and Analytic Considerations. This report describes the process used to link the 2014 NHCS and the 2014/2015 NDI data and includes an overview of the data sources, a description of the methods used for linkage, and analytic guidance for researchers.

Enhancing Identification of Opioid-involved Health Outcomes Using Linked Hospital Care and Mortality Data: Summary Report on Task 1. This report describes efforts to link data from the 2014 NHCS to data from the 2014/2015 NDI and DIM and provides example analyses that demonstrate the value of the linked data.

2016 NHCS Data with Enhanced Opioid-Identification Linked to the 2016-2017 NDI Linked to the 2016-2017 DIM Data Report. This report describes the three source datasets, provides information about the 2016 NHCS-enhanced opioid identification variables, and provides additional resources on the linkages.

Enhancing Identification of Opioid-involved Health Outcomes Using National Hospital Care Survey Data. This report summarizes the development of techniques to identify opioids in the 2016 hospital and death certificate data.

National Hospital Care Survey Demonstration Projects: Opioid-involved Emergency Department Visits, Hospitalizations, and Deaths. This National Health Statistics report demonstrates the utility of linking the three source datasets to study opioid-involved emergency department visits, hospitalizations, and mortality.

Opioid-involved Emergency Department Visits in the National Hospital Care Survey and the National Hospital Ambulatory Medical Care Survey. This National Health Statistics report utilized the enhanced opioid algorithm developed by the project by analyzing opioid-involved emergency department visits in the 2014 NHCS and the 2013-2016 National Hospital Ambulatory Care Survey.

National Hospital Care Survey Demonstration Projects: Mortality Following Nonfatal Opioid Overdose Visits to the Emergency Department. This National Health Statistics report utilized the 2016 NHCS data linked to 2016/2017 NDI and DIM data to report on mortality following nonfatal opioid overdose visits to the emergency department.

Annual Hospital Report Portal. Hospitals that submitted 12 months of administrative claims to the 2019 NHCS can view their data in this NCHS portal.

Project Final Report. The final report summarizes critical background information, major project accomplishments, lessons learned, and key products and publications resulting from project activities.