NCHS Linked Medicare Data for Health Research

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NCHS Linked Medicare Data for Health Research

• Special Projects Branch
• Office of Analysis and Epidemiology
• NCHS Data Users Conference
• August 13, 2008
• U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
• Centers for Disease Control and Prevention
• National Center for Health Statistics

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NCHS Record Linkage Program

• Links survey data with data collected from
  administrative records
  
• Designed to maximize the scientific value of the
  NCHS population-based surveys
  
• Examine factors that influence chronic disease,
  disability,health care utilization, morbidity,
  and mortality

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What is Record Linkage?
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Record Linkage Activities

• Mortality
• National Death Index
• Social Security Retirement and Disability
• Data from the Retirement, Survivors, Disability
  Insurance (RSDI) and Supplemental Security Income
  (SSI) programs
  
• Medicare enrollment and payments
• Enrollment and claims data

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Medicare 101

• Medicare eligibility groups
• 65 years and older
• Disabled
• End Stage Renal Disease
• Medicare components during this time period
• Part A (Hospital insurance)
• Part B (Medical insurance)
• Medicare data
• Claims based records for covered health services

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Medicare Linkage

• Medicare enrollment and claims data for the years
  1991-2000
  
• Denominator file
• MEDPAR Inpatient hospitalization
• MEDPAR Skilled nursing facility (SNF)
• Hospital outpatient
• Home Health Agency (HHA)
• Hospice
• Carrier (physician/supplier Part B file)
• Durable Medical Equipment (DMERC)
• Next data release (1999-2006)
• All of the above files
• Chronic Conditions Warehouse
• Medicare Part D (Prescription Drugs)

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Medicare Linkage

• Summary Medicare Enrollment and Claims Files
  (SMEC) for 1991-2000
  
• Enrollment information from the Denominator file
  plus summary variables of claims and payments
  
• Variables modeled after MCBS cost and use files
• Total reimbursements per year
• Total number of claims by Medicare record type
• Summary of charges by Medicare record type
• Termination status reason for termination
• Monthly HMO enrollment
• Medicare status code (i.e. Part A, B or both)

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NCHS Linked Medicare Data Files
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Research Potential of Linked Medicare Data

• Examine risk factors for health conditions
• Examine reliability of survey data
• Compare survey reported Medicare enrollment to
  Medicare claims records
  
• Examine survey report of disability with program
  participation eligibility criteria
  
• Examine disparities in Medicare service
  utilization

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Medicare Analytic Issues

• Eligibility status
• Eligible but not matched
• Death
• Linked but no Medicare data
• Managed care enrollment
• Non covered services
• Issues with Medicare data files
• See the NCHS-CMS linkage web page under
  Analytic/Programming Support

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Linkage Ineligibility

• Cannot attempt to link survey records to other
  data sources if respondent
  
• Refused to provide SSN or
• Lacks sufficient key identifying information
• These cases are INELIGIBLE for linkage and MUST
  BE DROPPED from all analysis
  
• They are not a random sample of respondents
• More of a problem for NHIS than for NHANES

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Medicare Ineligible Population and Linkage Rates
(65 years)
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Ineligibles and Non-Matches

• Must be excluded from your sample
• Identify using the variable (CMS_MATCH) on the
  Feasibility Study Data

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Identifying Deaths

• Survey participants interviewed before the
  availability of linked Medicare files could have
  died before 1991
  
• E.g. NHEFS, NHANES II or NHANES III
• Persons may die during study period and cease to
  have Medicare records
  
• Enrolled in Medicare in 1991 but died before 2000

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Identifying Deaths

• Survey respondents who died before 1991 (e.g.
  from NHANES) can be identified by merging
  mortality information from the Linked Mortality
  files
• Needed to create analytic sample
• Persons who died during 1991-2000 should no
  longer have Medicare records after date of death
  
• Look for a CMS date of death (DOD) on each of the
  Denominator or SMEC files (1991 to 2000)

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No Denominator Record

• Deceased prior to 1991
• check CMS date of death
• Loss of entitlement during 1991-2000
• check termination codes on Denominator or SMEC
  files (PART_A_TERM_CD and PART_B_TERM_CD)
  
• Deceased during 1991-2000
• Non payment of premium
• Voluntary withdrawal
• Other termination
• CMS record keeping inconsistencies

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No Denominator Record

• Lack of denominator record can affect your
  analytic sample why?
  
• Cant determine managed care enrollment
• In general, managed care enrollees are excluded
  from sample (more on this to come)
  

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Denominator recordbut no claims data

• Entitled to Medicare but not utilizing Medicare
  services during 1991-2000
  
• Entitled to Medicare but Medicare services being
  used are not reimbursable claims
  
• Note
• Small fraction of linked participants may have
  claims data but no associated Denominator record
  
• Some Medicare beneficiaries only enrolled in Part
  A
  
• CMS record keeping inconsistencies

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Managed Care Enrollment

• Medicare does not receive claims for
  beneficiaries enrolled in managed care plans
  (HMO)
  
• Do not have complete information on payments or
  services received
  
• Could miss health events that are being counted
  based upon submitted claims
  
• Complex issue. See ResDAC Technical brief at
  http//www.resdac.umn.edu/Tools/TBs/TN-009.asp

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Managed Care Enrollment

• Studies on reimbursements/charges
• Option may be to exclude those with any managed
  care enrollment because you dont have complete
  information on payments or services received
  
• Studies on health outcomes/events
• Option may be to exclude those with any managed
  care enrollment because you could miss events
  
• Option may be to censor observations at time of
  first HMO enrollment
  
• Other methods for addressing HMO enrollment
  possible depending upon research question

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Services not covered in Medicare 1991-2000 files

• Out-patient prescription drugs
• Routine physical and dental exams
• Dentures
• Eye glasses
• Out-of-pocket expenses for Medicare beneficiaries
  (e.g. deductibles, coinsurance)

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Final Tips

• Read relevant documentation !!!
• Survey file layouts detailed notes
• Linkage methodology reports
• Analytic guidelines
• Consult basic program information
• CMS http//www.cms.gov
• ResDAC http//www.resdac.umn.edu

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Final Tips

• Determine NCHS public-use files needed
• Determine RDC linked files needed
• Determine feasibility of research question based
  upon successfully linked respondents

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What is Feasibility Study Data?

• Public-use data indicating whether respondent was
  linked to Medicare data and whether there is a
  record on the various Medicare files
  
• Match status (CMS_MATCH)
• 1 Linked
• 2 Not linked
• 3 Ineligible
• 80 variables indicating which of the specific
  Medicare files and for which of the 10 years of
  Medicare data data is available

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Feasibility study data are in ascii format and
are survey specific. Feasibility data can be
downloaded fromhttp//www.cdc.gov/nchs/rd/nchs_
datalinkage/data_linkage_cms.htm
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Restricted Data Access Methods

• NCHS RDC, Hyattsville, MD
• On site
• Remote access
• Staff assisted, i.e. on-site programming for
  remote researchers
  
• Census RDC sites (9 locations)
• Restricted data files remain in RDC and output is
  inspected for disclosure violations

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Future Linkage Activities

• Continue Medicare Linkage
• Periodicity of linkages is outside NCHS control
• Current agreement includes Medicare Part D
• Medicaid
• Linkage of 1999-2004 Medicaid enrollment and
  claims data linked to 1999-2004 NHIS and NHANES

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Its too complicated???What to do????

• Review documentation
• http//www.cdc.gov/nchs/rd/nchs_datalinkage/data_
  linkage_cms.htm
  
• Contact ResDAC http//www.resdac.umn.edu/
• Free assistance in obtaining and using CMS data
  for research
  
• Workshops and presentations
• Statistics and other research resources