national hospital discharge survey: a hands-on workshop using public-use data files
DESCRIPTION
National Hospital Discharge Survey: A Hands-On Workshop Using Public-Use Data Files Michelle N. Podgornik, MPH 2006 Data Users Conference July 11, 2006 8:30am-10:00am Session #23. NHDS Background. - PowerPoint PPT PresentationTRANSCRIPT
National Hospital Discharge National Hospital Discharge Survey: A Hands-On WorkshopSurvey: A Hands-On Workshop
Using Public-Use Data FilesUsing Public-Use Data Files
Michelle N. Podgornik, MPHMichelle N. Podgornik, MPH
2006 Data Users Conference2006 Data Users ConferenceJuly 11, 2006July 11, 2006
8:30am-10:00am8:30am-10:00amSession #23Session #23
National probability survey of discharges from National probability survey of discharges from
non-federal, short-stay hospitals in the United non-federal, short-stay hospitals in the United
StatesStates
Conducted annually since 1965Conducted annually since 1965
Latest data available: 2004Latest data available: 2004
NHDS BackgroundNHDS Background
Three-Stage DesignThree-Stage Design
• Primary Sampling Units (PSUs)Primary Sampling Units (PSUs)
• HospitalsHospitals
• DischargesDischarges
NHDS DesignNHDS Design
AgeAge
SexSex
RaceRace
Source of paymentSource of payment
Discharge statusDischarge status
Marital statusMarital status
Patient DataPatient Data
Geographic regionGeographic region
Bed sizeBed size
OwnershipOwnership
Facility DataFacility Data
DiagnosesDiagnoses
Surgical and non-surgical proceduresSurgical and non-surgical procedures
International Classification of Diseases, 9International Classification of Diseases, 9 thth
Revision, Clinical Modification (ICD-9-CM)Revision, Clinical Modification (ICD-9-CM)
Medical DataMedical Data
Days of careDays of care
Month of dischargeMonth of discharge
Diagnosis-related groups (DRGs)Diagnosis-related groups (DRGs)
Analysis weightAnalysis weight
Additional DataAdditional Data
At the end of this session, you will be able to:At the end of this session, you will be able to:
• Understand some of the advantages and Understand some of the advantages and
limitations of using downloadable NHDS datalimitations of using downloadable NHDS data
• Successfully download data files from the Successfully download data files from the
Internet and create a SAS dataset for analysisInternet and create a SAS dataset for analysis
• Perform simple analyses using SASPerform simple analyses using SAS
Session GoalsSession Goals
AdvantagesAdvantages
• Obtain current data and data file documentationObtain current data and data file documentation
• Obtain diagnosis-related group (DRG) Obtain diagnosis-related group (DRG)
informationinformation
Using Online Data FilesUsing Online Data Files
LimitationsLimitations
• Only single-year data files from 1996 through Only single-year data files from 1996 through
2004 are available2004 are available
• Variables necessary to run SUDAAN are not Variables necessary to run SUDAAN are not
publicly availablepublicly available
Using Online Data FilesUsing Online Data Files
Download data and data file layout from the Download data and data file layout from the
NCHS website - NCHS website - http://www.cdc.gov/nchshttp://www.cdc.gov/nchs
Fixed width ASCII files are available for each Fixed width ASCII files are available for each
data collection year since 1996data collection year since 1996
Downloading DataDownloading Data
Downloaded data files must be “unzipped” Downloaded data files must be “unzipped”
using extraction software (e.g. WinZip)using extraction software (e.g. WinZip)
Your computer may have extraction software Your computer may have extraction software
pre-installed; if not, a free evaluation version pre-installed; if not, a free evaluation version
of WinZip is available at: of WinZip is available at:
http://www.winzip.com/downwzeval.htm?wzdmhttp://www.winzip.com/downwzeval.htm?wzdm
Extracting DataExtracting Data
Each document includes:Each document includes:
• A description of the NHDS, including survey A description of the NHDS, including survey
methodologymethodology
• File layoutFile layout
• Parameters and equations used to calculate Parameters and equations used to calculate
relative standard errors, a measure of the relative standard errors, a measure of the
reliability of an estimatereliability of an estimate
Data File DocumentationData File Documentation
Each document also includes:Each document also includes:
• ICD-9-CM code changesICD-9-CM code changes
• Census population estimatesCensus population estimates
• Unweighted and weighted frequencies of Unweighted and weighted frequencies of
selected variablesselected variables
• Medical Abstract FormMedical Abstract Form
Data File Documentation ( - cont’d - )Data File Documentation ( - cont’d - )
Select “Extract All…” from the drop-down menu
Double-click: Double-click: My ComputerMy Computer
Double-click:Double-click: Local Disk (C:)Local Disk (C:)
Double-click:Double-click: 2006 Data Users Conference2006 Data Users Conference
Double-click:Double-click: ExercisesExercises
Hands-On ExercisesHands-On Exercises
Creating a SAS datasetCreating a SAS dataset
Generating simple unweighted and weighted Generating simple unweighted and weighted
frequenciesfrequencies
Calculating first-listed, any-listed, and all-listed Calculating first-listed, any-listed, and all-listed
diagnosesdiagnoses
Calculating all-listed proceduresCalculating all-listed procedures
Hands-On ExercisesHands-On Exercises
Exercise #1Exercise #1
Creating a SAS datasetCreating a SAS dataset
Exercise #2Exercise #2
Generating simple unweighted frequenciesGenerating simple unweighted frequencies
Exercise #3Exercise #3
Generating simple weighted frequenciesGenerating simple weighted frequencies
Exercise #4Exercise #4
Calculating first-listed diagnosesCalculating first-listed diagnoses
DefinitionDefinition
First-listed diagnosisFirst-listed diagnosis
• Principal diagnosis (if specified) or the Principal diagnosis (if specified) or the
diagnosis listed first on the medical record face diagnosis listed first on the medical record face
sheetsheet
Exercise #5Exercise #5
Calculating any-listed diagnosesCalculating any-listed diagnoses
DefinitionDefinition
Any-listed diagnosisAny-listed diagnosis
• The occurrence of a diagnosis at least once in The occurrence of a diagnosis at least once in
a record, regardless of positiona record, regardless of position
Exercise #6Exercise #6
Calculating all-listed diagnosesCalculating all-listed diagnoses
DefinitionDefinition
All-listed diagnosisAll-listed diagnosis
• Total number of times (up to seven) that a Total number of times (up to seven) that a
diagnosis appears in a recorddiagnosis appears in a record
Exercise #7Exercise #7
Calculating all-listed proceduresCalculating all-listed procedures
DefinitionDefinition
All-listed procedureAll-listed procedure
• Total number of times (up to four) that a Total number of times (up to four) that a
procedure appears in a recordprocedure appears in a record
Reliability of EstimatesReliability of Estimates
Estimates should be based on at least 30 Estimates should be based on at least 30
sample recordssample records
Estimates should also have a relative Estimates should also have a relative
standard error (RSE) of less than 30 percentstandard error (RSE) of less than 30 percent
Combine multiple years of data until you have Combine multiple years of data until you have
at least 30 raw cases in cells of interestat least 30 raw cases in cells of interest
RSE improves with the number of years RSE improves with the number of years
combinedcombined
How To Increase ReliabilityHow To Increase Reliability
Multi-year data file CD-ROMMulti-year data file CD-ROM
• Admission month is available on the multi-year Admission month is available on the multi-year
data file but not on the single-year data filesdata file but not on the single-year data files
• Diagnostic-related group (DRG) information is Diagnostic-related group (DRG) information is
available on the single-year data files but not available on the single-year data files but not
on the multi-year data fileon the multi-year data file
• Order of variables slightly differentOrder of variables slightly different
Other Sources of Public-Use Other Sources of Public-Use DataData
Visit the NHDS website Visit the NHDS website
http://www.cdc.gov/nchs/nhds.htmhttp://www.cdc.gov/nchs/nhds.htm
Contact the Hospital Care Statistics Branch by Contact the Hospital Care Statistics Branch by
calling 301-458-4321 or by e-mailing calling 301-458-4321 or by e-mailing
[email protected]@cdc.gov
How to Obtain More InformationHow to Obtain More Information
To request electronic copies of this To request electronic copies of this
PowerPoint presentation and the SAS PowerPoint presentation and the SAS
exercises, please send an e-mail to exercises, please send an e-mail to
Michelle Podgornik at Michelle Podgornik at [email protected]