STATUS: Completed Project
National Center for Health Statistics (NCHS) worked with state offices to establish the National Death Index (NDI), which is a centralized database of death record information on file in state vital statistics offices. The NDI is a resource that helps epidemiologists and other health and medical investigators with their research. In particular, the NDI is used for mortality ascertainment to assess the causes and risk factors of diseases and conditions and for the effectiveness of a wide range of interventions and drug therapies.
PROJECT PURPOSE & GOALS
Through collaboration between the CDC, CMS, and FDA, the overall goal of this project was to increase the availability of information on the cause of death by linking NDI data to other sources. Enabling linkages will allow researchers to develop national estimates of cause-specific death rates following emergency department (ED) visits and/or hospital stays for specific conditions.
The CDC objectives included:
Link the 2014 NHCS inpatient and emergency department (ED) claims data to the 2014 and 2015 NDI (to ensure at least 12 months of post-discharge follow up for each hospital event).
Link the 2014 CMS Master Beneficiary Summary File (MBSF) and Chronic Conditions Warehouse (CCW) to 2014 and 2015 NDI.
Link the 2016 NHCS inpatient and ED claims and EHR data to the 2016 and 2017 NDI.
Develop a long-term strategy for the access and use of NDI to support PCOR.
The FDA objectives include:
To develop standard, repeatable, and efficient technical solutions for linking the NDI’s death and cause of death data to large, commercially and publicly insured populations.
To demonstrate the feasibility of linkage by using use cases to assess associations between select medications and death or cause of death as an outcome.
The CMS objectives include:
Purchase NDI data to link to Medicare decedents data from 2008-2016 and Medicaid decedents data from 2007-2015.
Link the NDI data on cause and manner of death with claims data to produce updated Medicare and Medicaid research files.
PROJECT ACHIEVEMENTS AND HIGHLIGHTS
For the project “Adding Cause-Specific Mortality to the NHCS by Linking to the NDI,” the CDC project team produced linkages of patient EHRs and national mortality data. The project team also created new methods to optimize data linkages when using large national data files.
To develop a strategic plan for improving the NDI, the CDC project team surveyed state vital registration officials, conducted interviews with federal researchers, and held a NDI Workshop with state registration officials, Federal researchers, and academic researchers. After synthesizing findings, the CDC team convened a series of meetings with agency partners to discuss improving the NDI, resulting in the formation of a Federal Interagency Workgroup on Mortality Data System Improvement.
For the project “Pilot Linkage of National Death Index+ to Commercially and Publicly Insured Populations,” the FDA project team developed processes for matching patient records across the health plans and piloted a process for sharing data between multiple health plan databases, while protecting private health information. The team also conducted an analysis that demonstrated the usefulness of a standardized NDI linkage process to assess drug safety and effectiveness, adverse event surveillance, and comparative effectiveness research in distributed data networks.
As part of the project, “Enhancing Data Resources for Researching Patterns of Mortality in PCOR,” the CMS project team successfully linked the NDI’s death and cause of death data with the MBSF and the Medicaid Enrollee Supplemental File (MESF). The linked data have been used to probe a range of topic areas including cancer and blood disorders surveillance, mortality risk-factors for colorectal cancer, and diabetes surveillance.
PUBLICATIONS, PRESENTATIONS, AND OTHER PUBLICALLY AVAILABLE RESOURCES
The FDA team produced their final report, “Enhancing Data Resources for Studying Patterns and Correlates of Mortality in Patient-Centered Outcomes Research: Pilot Linkage of National Death Index+ to Commercially and Publicly insured Populations”. The report is available here: https://aspe.hhs.gov/sites/default/files/documents/c1489e4813e81e7185260fc7c674f6c0/FDA-Final-Report-NDI-Claims-Data-Linkage-sl.pdf
The CDC developed a final report for the “Adding Cause-Specific Mortality to the NHCS by Linking to the NDI” project, which summarizes the linkage methodology used to link the NHCS to the NDI to obtain cause-specific mortality. The report is available here: https://aspe.hhs.gov/sites/default/files/private/pdf/259016/cdc-project-1-final-report.pdf
The CDC team developed a final report that summarizes findings on barriers to the NDI and discusses how the NDI can be improved for research. The report is available here: https://aspe.hhs.gov/sites/default/files/private/pdf/259016/NDI-Non-Economic-Barriers-Report-508.pdf
The CMS team developed a final report for the “Enhancing Data Resources for Researching Patterns of Mortality in PCOR” project. The report is available here: https://aspe.hhs.gov/sites/default/files/private/pdf/259016/HP-17-002-FinalReport.pdf
The linked 2014 NHCS claims data and 2014/2015 NDI data files are available for research use: https://www.cdc.gov/nchs/data-linkage/nhcs-ndi.htm
- The CDC project team developed a codebook for the linked data file: https://www.cdc.gov/nchs/data/datalinkage/LMF2015_DataDictionary.pdf
- The CDC project team published a methodology report “The Linkage of the 2014 National Hospital Care Survey to the 2014/2015 National Death Index,” which is available here: https://www.cdc.gov/nchs/data/datalinkage/NHCS14_NDI14_15_Methodology_Analytic_Consider.pdf
The linked 2014 NHCS claims data and 2014/2015 CMS MBSF data files are available for research use: https://www.cdc.gov/nchs/data-linkage/CMS-Medicare-Restricted.htm
- The CDC project team published a report describing the methods used for linkage and analytic considerations for the linked 2014 NHCS and 2014/2015 CMS MBSF data: https://www.cdc.gov/nchs/data/datalinkage/NHCS-CMS-Medicare-Llinkage-Methods-and-Analytic-Considerations.pdf
The linked 2016 NCHS claims and EHR records and the 2016/2017 NDI data files are available for research use: https://www.cdc.gov/nchs/data-linkage/nhcs-ndi.htm
- The CDC project team published a report describing the methods used for linkage and the analytic considerations for the linked dataset, which is available here: https://www.cdc.gov/nchs/data/datalinkage/NHCS16_NDI16_17_Methodology_Analytic_Consider.pdf
The linked data files created by the CMS project, “Enhancing Data Resources for Researching Patterns of Mortality in PCOR,” were posted on the ResDAC and CCW websites.
- The CCW files can be found here: https://www.ccwdata.org/web/guest/data-dictionaries
- The ResDAC files are available here: https://www.resdac.org/cms-data/files/mbsf
A list of publications that use the linked NHCS data files is available here: https://www.cdc.gov/nchs/data/datalinkage/NHCS-Linked-Mortality-Files-Citation-List-20210104-508.pdf
The CDC project team published six research reports to demonstrate the utility of the linked dataset developed under the “Adding Cause-Specific Mortality to the NHCS by Linking to the NDI” project.
- A National Health Statistics Report titled, “National Hospital Care Survey Demonstration Projects: Characteristics of Inpatient and Emergency Department Encounters Among Patients With Any Listed Diagnosis of Alzheimer Disease,” which is available here: https://www.cdc.gov/nchs/data/nhsr/nhsr121-508.pdf
- A National Health Statistics Report titled, “Respiratory Illness Emergency Department Visits in the National Hospital Care Survey and the National Hospital Ambulatory Medical Care Survey,” which is available here: https://www.cdc.gov/nchs/data/nhsr/nhsr151-508.pdf
- A National Health Statistics Report titled, “National Hospital Care Survey Demonstration Projects: Stroke Inpatient Hospitalizations,” which is available here: https://www.cdc.gov/nchs/data/nhsr/nhsr132-508.pdf
- A National Health Statistics Report titled, “Opioid-involved Emergency Department Visits in the National Hospital Care Survey and the National Hospital Ambulatory Medical Care Survey,” which is available here: https://www.cdc.gov/nchs/data/nhsr/nhsr149-508.pdf
- A National Health Statistics Report titled, “National Hospital Care Survey Demonstration Projects: Opioid-involved Emergency Department Visits, Hospitalizations, and Deaths,” which is available here: https://www.cdc.gov/nchs/data/nhsr/nhsr141-508.pdf
- A National Vital Statistics Report titled, “Maternal Mortality in the United States: Changes in Coding, Publication, and Data Release, 2018,” which is available here: https://www.cdc.gov/nchs/data/nvsr/nvsr69/nvsr69-02-508.pdf
- The FDA project team published a methods study protocol for the project “Pilot Linkage of National Death Index+ to Commercially and Publicly Insured Populations” in the Journal of Medical Internet Research. The publication is available here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7669437/
Below is a list of ASPE-funded PCORTF projects that are related to this project
Improving the Mortality Data Infrastructure for Patient-Centered Outcomes – Comprised of all U.S. mortality events since 1979, the NDI database allows researchers to match entries in the NDI to those participating in longitudinal clinical and epidemiologic studies to determine both fact and cause of death. A significant challenge with the NDI has been the lag between the date of death and the availability of the record for matching purposes. The CDC’s NCHS worked to improve the infrastructure to support more timely and complete mortality data collection through more timely delivery of state death records (e.g., cause of death) to the NDI database and through linking NDI records with nationally collected hospital datasets to obtain a more complete picture of patient care.