The data linkage work was performed at NCHS under contract by NORC at the University of Chicago with funding from the Department of Health and Human Services’ Office of the Secretary Patient-Centered Outcomes Research Trust Fund (OS-PCORTF).
The essential goal of the project is the creation of two linked data sets that are available to outside researchers (with an approved project application at the NCHS Research Data Center (RDC):
- National Hospital Care Survey (NHCS) patient records – National Death Index records
- Linked data indicates that NHCS patient has died subsequent to hospitalization
- National Hospital Care Survey (NHCS) patient records – CMS Master Beneficiary Records
- Linked data indicates NHCS patient was enrolled in Medicare at or around time of hospitalization
The National Center for Health Statistics (NCHS) houses unique national data resources and expertise, including (1) the National Hospital Care Survey (NHCS), which provides statistics on health and health care utilization based on patient hospital and emergency department (ED) visits, medical claims records and Electronic Health Records (EHRs), as well as information on provider and patient characteristics; and the NCHS Data Linkage Program, which has substantial statistical and methodological expertise in creating, managing and analyzing multisource linked files.
NCHS has linked data from the 2014 and 2016 NHCS to death record information from the National Death Index (NDI); and separately the 2014 NHCS to administrative data from the Centers for Medicare & Medicaid Services (CMS) Chronic Conditions Warehouse (CCW), specifically the Master Beneficiary Summary File (MBSF). Together these linkages will enable the development of estimates of cause-specific death rates following ED visits and/or hospital inpatient stays for specific conditions.
Linkage was developed using an enhanced version of Fellegi-Sunter methodology to replace existing methods used by the NCHS Special Projects Branch (SPB). For this version the processing of the linkage was custom-coded by NORC in SAS.
As per the objective of the project, linked data files were produced.
Subsequent to completion additional contracts for linkage to NHCS were awarded to NORC by NCHS:
- Technical Support to Link the National Hospital Care Survey Data to Centers for Medicare & Medicaid Services and Housing and Urban Development Data
- Technical Support to conduct privacy preserving record linkage methodological work and to Link the National Hospital Care Survey Data to Centers for Medicare & Medicaid Services T-MSIS data