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National Center for Health StatisticsNational Center for Health StatisticsOffice of Analysis and EpidemiologyOffice of Analysis and Epidemiology

Special Projects BranchSpecial Projects BranchRecord Linkage ProgramRecord Linkage Program

Christine S. Cox, SPB Branch Chief, OAEChristine S. Cox, SPB Branch Chief, OAENCHS Board of Scientific Counselors MeetingNCHS Board of Scientific Counselors Meeting

April 24, 2008April 24, 2008

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES Centers for Disease Control and PreventionCenters for Disease Control and PreventionNational Center for Health StatisticsNational Center for Health Statistics

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NCHS Organizational NCHS Organizational ChartChart

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Data Linkage & Tracking Data Linkage & Tracking TeamsTeams

Data Linkage TeamData Linkage Team Stephanie Bartee (contractor)Stephanie Bartee (contractor) Jim Brittain (contractor)Jim Brittain (contractor) Cordell GoldenCordell Golden Kimberly LochnerKimberly Lochner Donna MillerDonna Miller Gloria WheatcroftGloria Wheatcroft

Data Tracking TeamData Tracking Team Dawn ScottDawn Scott Keith ZevallosKeith Zevallos

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Why Do LinkageWhy Do Linkage Augments available information for Augments available information for

major diseases, risk factors, and health major diseases, risk factors, and health service utilizationservice utilization Links exposures to outcomesLinks exposures to outcomes Provides longitudinal component to survey Provides longitudinal component to survey

datadata Reduces cost burdenReduces cost burden

Re-contacting survey respondents for follow-Re-contacting survey respondents for follow-up information can be expensiveup information can be expensive

Increases accuracy and detail of data Increases accuracy and detail of data collectedcollected

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Types of Data LinkageTypes of Data Linkage

Person-level or facility level recordPerson-level or facility level record Person survey data linked with administrative Person survey data linked with administrative

data (e.g. Medicare)data (e.g. Medicare) Hospital survey data linked facility Hospital survey data linked facility

characteristics (e.g. American Hospital characteristics (e.g. American Hospital Associations Annual Survey of Hospitals)Associations Annual Survey of Hospitals)

Contextual dataContextual data Geocoded to standard Census geo-areasGeocoded to standard Census geo-areas

Census data – population & housingCensus data – population & housing EPA data – Environmental air qualityEPA data – Environmental air quality State level data – generosity of Medicaid paymentsState level data – generosity of Medicaid payments

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How Records are LinkedHow Records are Linked

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Research Potential of Research Potential of NCHS Linked DataNCHS Linked Data

AgingAging Risk factors for poor health outcomes (hip fractures, Risk factors for poor health outcomes (hip fractures,

stroke, etc.)stroke, etc.) DisabilityDisability

Effects of chronic illness and obesity on disability and Effects of chronic illness and obesity on disability and mortalitymortality

DisparitiesDisparities Mortality patterns by race/ethnicity or socioeconomic Mortality patterns by race/ethnicity or socioeconomic

statusstatus Health ServicesHealth Services

Functional impairment and health care costsFunctional impairment and health care costs GeneticsGenetics

Genetic variants and health outcomesGenetic variants and health outcomes Methodologic StudiesMethodologic Studies

Validation of self-reports vs. administrative recordsValidation of self-reports vs. administrative records

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NCHS Linkage ProgramNCHS Linkage Program

Early 1980’sEarly 1980’s NMCUES link to Medicare in 1981-1986NMCUES link to Medicare in 1981-1986 NHEFSNHEFS

NDI linkage in 1982-1992NDI linkage in 1982-1992 Medicare linkage in 1980-1986Medicare linkage in 1980-1986

1990’s – NHIS mortality linkage to NDI1990’s – NHIS mortality linkage to NDI 2000 to present – NCHS expanded linkage 2000 to present – NCHS expanded linkage

programprogram Division specific linkagesDivision specific linkages OAE/SPB record linkagesOAE/SPB record linkages

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Division Linkage Division Linkage ActivitiesActivities

Division of Vital StatisticsDivision of Vital Statistics Linked Birth and Infant Death FilesLinked Birth and Infant Death Files

1983-1991 (birth cohort linkage)1983-1991 (birth cohort linkage) 1995-2004 (period and birth cohort linkages)1995-2004 (period and birth cohort linkages)

Division of Health Care StatisticsDivision of Health Care Statistics 2004 National Nursing Home Survey2004 National Nursing Home Survey

CMS Long Term Care Minimum Data Set on resident CMS Long Term Care Minimum Data Set on resident assessments and facility characteristicsassessments and facility characteristics

Division of Health Interview SurveyDivision of Health Interview Survey Medical Expenditure Panel Survey (MEPS) Medical Expenditure Panel Survey (MEPS)

Linkage FilesLinkage Files NHIS survey cohorts are linked by person NHIS survey cohorts are linked by person

identification numberidentification number

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OAE Record Linkage OAE Record Linkage ActivitiesActivities

MortalityMortality National Death IndexNational Death Index

Retirement and DisabilityRetirement and Disability Social Security data from the Social Security data from the

Retirement, Survivors, Disability Retirement, Survivors, Disability Insurance (RSDI) and Supplemental Insurance (RSDI) and Supplemental Security Income (SSI) programsSecurity Income (SSI) programs

Medicare enrollment and paymentsMedicare enrollment and payments Enrollment and claims dataEnrollment and claims data

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Summary Linked Mortality Summary Linked Mortality Data FilesData Files

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Research Potential of Research Potential of Linked Linked

Mortality DataMortality Data

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Linked Medicare FilesLinked Medicare Files

Medicare enrollment and claims data for Medicare enrollment and claims data for the years 1991-2000the years 1991-2000 Denominator fileDenominator file MEDPAR Inpatient hospitalizationMEDPAR Inpatient hospitalization MEDPAR Skilled nursing facility (SNF)MEDPAR Skilled nursing facility (SNF) Hospital outpatientHospital outpatient Home Health Agency (HHA)Home Health Agency (HHA) HospiceHospice Carrier (physician/supplier Part B file)Carrier (physician/supplier Part B file) Durable Medical Equipment (DMERC)Durable Medical Equipment (DMERC)

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Research Potential of Research Potential of LinkedLinked

Medicare DataMedicare Data Examine risk factors for health Examine risk factors for health

conditionsconditions Examine reliability of survey dataExamine reliability of survey data

Compare survey reported Medicare Compare survey reported Medicare enrollments to Medicare claims recordsenrollments to Medicare claims records

Examine survey report of disability with Examine survey report of disability with program participation eligibility criteriaprogram participation eligibility criteria

Examine disparities in Medicare Examine disparities in Medicare service utilizationservice utilization

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Research Potential of Research Potential of LinkedLinked

Medicare DataMedicare Data Examine risk factors for health Examine risk factors for health

conditionsconditions Examine reliability of survey dataExamine reliability of survey data

Compare survey reported Medicare Compare survey reported Medicare enrollment to Medicare claims recordsenrollment to Medicare claims records

Examine survey report of disability with Examine survey report of disability with program participation eligibility criteriaprogram participation eligibility criteria

Examine disparities in Medicare Examine disparities in Medicare service utilizationservice utilization

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Publications & Current Publications & Current ProjectsProjects

Using Linked Medicare DataUsing Linked Medicare Data Publications:Publications:

Looker AC. Mussolino ME. Serum 25-Looker AC. Mussolino ME. Serum 25-hydroxyvitamin D and hip fracture risk in older hydroxyvitamin D and hip fracture risk in older U.S. white adults. Journal of Bone & Mineral U.S. white adults. Journal of Bone & Mineral Research. 23(1): 143-150, 2008 Jan.Research. 23(1): 143-150, 2008 Jan.

Current Projects:Current Projects: Assessing the Economic Burden of Chronic Assessing the Economic Burden of Chronic

Kidney Disease in the United StatesKidney Disease in the United States The Association of Obesity and Overweight with The Association of Obesity and Overweight with

Higher Medical Care Costs in Medicare Higher Medical Care Costs in Medicare BeneficiariesBeneficiaries

Comparing Self-Reported Chronic Conditions Comparing Self-Reported Chronic Conditions with Medicare Claims Datawith Medicare Claims Data

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Linked Social Security Linked Social Security FilesFiles

Retirement, Survivor, & Disability IncomeRetirement, Survivor, & Disability Income Master Beneficiary Record (MBR), 1962-2003Master Beneficiary Record (MBR), 1962-2003

Program eligibility, benefit amount, payment status, Program eligibility, benefit amount, payment status, dual entitlementdual entitlement

Payment History Update System (PHUS), 1984-Payment History Update System (PHUS), 1984-20032003

Benefit payment amounts, including withholding Benefit payment amounts, including withholding information for Medicare Part B premiumsinformation for Medicare Part B premiums

Supplemental Security IncomeSupplemental Security Income Supplement Security Record (SSR), 1974 to 2003Supplement Security Record (SSR), 1974 to 2003

Program eligibility, benefit information, and payment Program eligibility, benefit information, and payment statusstatus

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Social Security LinkageSocial Security Linkage

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Research Potential of Research Potential of Linked Social Security DataLinked Social Security Data

Examine reliability of survey information for Examine reliability of survey information for SSA program participation and benefitsSSA program participation and benefits

Compare the health characteristics of early Compare the health characteristics of early retirees (age 62) to those who postpone retirees (age 62) to those who postpone benefitsbenefits

Policy and analysis using validated survey dataPolicy and analysis using validated survey data Predicting the number of people who will become Predicting the number of people who will become

disabled based upon survey reported health disabled based upon survey reported health conditionsconditions

Determining whether current disability entitlement Determining whether current disability entitlement funding levels will be adequate as the population funding levels will be adequate as the population agesages

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Publications & Current Publications & Current ProjectsProjects

Using Linked Social Security Using Linked Social Security DataData

Publications:Publications: Riley GF. Health Insurance and Access to Care Riley GF. Health Insurance and Access to Care

among Social Security Disability Insurance among Social Security Disability Insurance Beneficiaries during the Medicare Waiting Beneficiaries during the Medicare Waiting Period. Inquiry 43:222-230, 2006 Fall.Period. Inquiry 43:222-230, 2006 Fall.

Current Project:Current Project: The Importance of Objective Health Measures The Importance of Objective Health Measures

in Predicting Exit From the Labor Force Via in Predicting Exit From the Labor Force Via Early OA, DI, and SSI ProgramsEarly OA, DI, and SSI Programs

Where Are They Now? The Subsequent Labor-Where Are They Now? The Subsequent Labor-Force Participation and Health Status of Force Participation and Health Status of Rejected Disability ApplicantsRejected Disability Applicants

Concordance between Self-Reports of SSDI Concordance between Self-Reports of SSDI Application & ReceiptApplication & Receipt

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ChallengesChallenges

Obtaining informed consentObtaining informed consent Improving identification dataImproving identification data Developing interagency Developing interagency

agreementsagreements Balancing limited resourcesBalancing limited resources Improving data accessImproving data access

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Informed ConsentInformed Consent

Satisfying institutional Satisfying institutional requirements for permission to requirements for permission to linklink

Communicating the importance Communicating the importance of record linkage to survey of record linkage to survey respondents and gaining their respondents and gaining their cooperationcooperation

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NHIS Participants NHIS Participants Providing SSNProviding SSN

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2007 NHIS split-ballot 2007 NHIS split-ballot experimentexperiment

Tested two options for obtaining consent Tested two options for obtaining consent to record linkageto record linkage Treatment 1: Ask permission to link survey Treatment 1: Ask permission to link survey

data with health-related records of other data with health-related records of other government agenciesgovernment agencies

If no, endIf no, end If yes, ask for last four digits of SSNIf yes, ask for last four digits of SSN

Treatment 2: Ask last four digits of SSN; Treatment 2: Ask last four digits of SSN; consent to link embedded in the questionconsent to link embedded in the question

If partial SSN reported, endIf partial SSN reported, end If partial SSN not reported, as permission to link If partial SSN not reported, as permission to link

without itwithout it

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NHIS Split-Ballot ResultsNHIS Split-Ballot Results

Treatment 2 was associated with Treatment 2 was associated with significantly higher odds of consent significantly higher odds of consent overall, and consent with or without overall, and consent with or without an SSN, compared to treatment 1an SSN, compared to treatment 1

Treatment 2 substantially increased Treatment 2 substantially increased the percentage of sample adults the percentage of sample adults consenting to record linkage consenting to record linkage compared to 2005-06compared to 2005-06

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NHIS Participants NHIS Participants Providing SSNProviding SSN

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Next StepsNext Steps

Design and test matching Design and test matching algorithms that utilize last four algorithms that utilize last four digits of SSNdigits of SSN

Work with other agencies who Work with other agencies who currently require all 9 digits of currently require all 9 digits of SSN for linkageSSN for linkage

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Identification DataIdentification Data

Incomplete or inaccurate Incomplete or inaccurate identification data from the identification data from the survey interview can lead to survey interview can lead to potential biases in linked data potential biases in linked data filesfiles NamesNames AddressesAddresses

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NamesNames

Issues with collection and Issues with collection and cleaning of survey participant cleaning of survey participant namesnames Created standardized procedure to Created standardized procedure to

identify non-names in survey dataidentify non-names in survey data Developed nickname to proper Developed nickname to proper

name conversion tablename conversion table

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AddressesAddresses

Important to keep address information Important to keep address information currentcurrent Improve linkage accuracyImprove linkage accuracy Particularly important for common surnamesParticularly important for common surnames

Conduct passive trackingConduct passive tracking National change of address matchesNational change of address matches Standardize and update addressesStandardize and update addresses Address updates current as of June 2007Address updates current as of June 2007 Now geo-coding new address dataNow geo-coding new address data

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Interagency AgreementsInteragency Agreements

Complexity in drafting agreementsComplexity in drafting agreements Agency differences in legislative Agency differences in legislative

mandates and requirements to mandates and requirements to protect data and survey respondent protect data and survey respondent confidentialityconfidentiality

Resolving issues of data ownership Resolving issues of data ownership and access to linked data files, e.g.and access to linked data files, e.g. Can a public-use file be created?Can a public-use file be created? If restricted access required, where will If restricted access required, where will

data reside? Who will control access?data reside? Who will control access?

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Interagency AgreementsInteragency Agreements NCHS taking leadership role in working NCHS taking leadership role in working

across federal agencies through Federal across federal agencies through Federal Committee on Statistical Methodology Committee on Statistical Methodology (FCSM)(FCSM) 2006: NCHS & Census presentation highlighting 2006: NCHS & Census presentation highlighting

difficulties in developing agreementsdifficulties in developing agreements Included a recommendation that FCSM facilitate the Included a recommendation that FCSM facilitate the

development of a IAA templatedevelopment of a IAA template 2008: FCSM convenes sub-committee on usage 2008: FCSM convenes sub-committee on usage

of administrative recordsof administrative records Defining best practices across federal agenciesDefining best practices across federal agencies Developing an interagency agreement template for Developing an interagency agreement template for

record linkage projectsrecord linkage projects

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Balancing Limited Balancing Limited ResourcesResources

Limited resources to both assist data Limited resources to both assist data users and conduct new linkagesusers and conduct new linkages Developing user documentation, web Developing user documentation, web

pages, analytic guideline & other user pages, analytic guideline & other user toolstools

Transforming administrative data into Transforming administrative data into analytic dataanalytic data

Providing technical assistance to data Providing technical assistance to data usersusers

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Data User ToolsData User Tools

File layouts & detailed notesFile layouts & detailed notes Sample SAS & STATA input statements Sample SAS & STATA input statements

for public-use linked mortality filesfor public-use linked mortality files Dummy dataDummy data Matching methodology reportsMatching methodology reports Linkage rates for SSA & CMS linked Linkage rates for SSA & CMS linked

datadata Analytic guidelinesAnalytic guidelines

Weighting and variance estimation (NHIS)Weighting and variance estimation (NHIS)

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Data User Tools (cont.)Data User Tools (cont.)

Summary Medicare and SSA filesSummary Medicare and SSA files Feasibility data files for SSA & CMS Feasibility data files for SSA & CMS

Files – Download from webFiles – Download from web Comparative analysis of the public-Comparative analysis of the public-

use and restricted-use linked use and restricted-use linked mortality datamortality data

Compare the mortality experience of Compare the mortality experience of the NHIS linked mortality cohorts to the NHIS linked mortality cohorts to U.S. populationU.S. population

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Data AccessData Access

Expand data access for restricted filesExpand data access for restricted files Expand RDC locations (e.g. NCHS Expand RDC locations (e.g. NCHS

restricted data now accessible through 9 restricted data now accessible through 9 Census RDCs)Census RDCs)

Create designated agentsCreate designated agents Create public use file, possible but Create public use file, possible but

difficultdifficult Assess disclosure riskAssess disclosure risk Develop synthetic public-use micro data Develop synthetic public-use micro data

files that are analytically useful and validfiles that are analytically useful and valid

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Public-use Linked Public-use Linked Mortality FilesMortality Files

Risk of survey participant re-identification Risk of survey participant re-identification required restricted-use designation for the required restricted-use designation for the most recent mortality updatemost recent mortality update

Great degree of motivation to create public-Great degree of motivation to create public-use linked mortality files to enhance use linked mortality files to enhance utilizationutilization Developed perturbation strategy to ensure Developed perturbation strategy to ensure

protection of respondent identity, while protection of respondent identity, while maintaining statistical validitymaintaining statistical validity

Conducted comparative study to determine Conducted comparative study to determine whether findings based upon the public-use files whether findings based upon the public-use files reproduce those using the restricted-use files.reproduce those using the restricted-use files.

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Selected Variables on the Selected Variables on the NHIS Linked Mortality FilesNHIS Linked Mortality Files

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Comparative Analyses Comparative Analyses ResultsResults

The public-use linked mortality files The public-use linked mortality files (NHIS, NHANES III, and LSOA II), (NHIS, NHANES III, and LSOA II), with a limited amount of perturbed with a limited amount of perturbed data and reduced number of data and reduced number of mortality variables, yield similar mortality variables, yield similar results as the restricted-use dataresults as the restricted-use data

Findings from the NHIS comparative Findings from the NHIS comparative analyses forthcoming in the analyses forthcoming in the American Journal of EpidemiologyAmerican Journal of Epidemiology

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OutreachOutreach

AnnouncementsAnnouncements ListservesListserves HCFO, AMSTAT NewsHCFO, AMSTAT News

PresentationsPresentations Conferences: APHA, SER, PAA, JSM, Conferences: APHA, SER, PAA, JSM,

NCHS DUCNCHS DUC Committees: CNSTAT, NCVHSCommittees: CNSTAT, NCVHS Agencies: CBO, CMSAgencies: CBO, CMS

WorkshopsWorkshops Academy Health, SER, ASHEAcademy Health, SER, ASHE

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Future Linkage ActivitiesFuture Linkage Activities

Periodic Mortality LinkagePeriodic Mortality Linkage Plan to conduct mortality linkage every Plan to conduct mortality linkage every

three yearsthree years Develop both restricted and public-use Develop both restricted and public-use

versionsversions Continue Medicare and Social Continue Medicare and Social

Security LinkageSecurity Linkage Periodicity of these linkages is outside Periodicity of these linkages is outside

NCHS controlNCHS control

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Future Linkage ActivitiesFuture Linkage Activities MedicaidMedicaid

Multi-agency collaborative project exploring Multi-agency collaborative project exploring differences in survey and program estimates of differences in survey and program estimates of Medicaid enrollmentMedicaid enrollment

2001-2002 NHIS linked to MSIS data files2001-2002 NHIS linked to MSIS data files Comparison of NHIS survey estimates of Medicaid Comparison of NHIS survey estimates of Medicaid

enrollment with counts from CPSenrollment with counts from CPS Expansion of partnership planned to include collection Expansion of partnership planned to include collection

of linked Medicaid data for NHIS and NHANESof linked Medicaid data for NHIS and NHANES

State based linkagesState based linkages State Cancer RegistriesState Cancer Registries

National Program of Cancer Registries (NPCR)National Program of Cancer Registries (NPCR) SEER registriesSEER registries