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Discharge Abstract Database (DAD)

A collaboration between CIHI and DLI

April 2013

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Canadian Institute for Health Information (CIHI) - Overview

• Mandate: To provide accurate and timely information required for

−Sound health policy

−Effective management of the health system

−Public awareness about factors affecting good health

• 27 databases of comparable health information– Health care services: primary health care, hospital care,

specialized services, community and pharmaceutical care

– Health spending: by geography and by category

– Health workforce: physicians, nurses, and other health care providers

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Collaboration between CIHI and Statistics Canada’s DLI

• CIHI recently developed a Data Access Strategy

• Purpose: To improve timeliness and accessibility of data to users such as system planners, policy makers, and researchers

– Streamlining CIHI’s existing data dissemination channels

– Exploring new, trusted data dissemination channels

• Resulted in a collaboration with Statistics Canada to make CIHI data more accessible to academic researchers using the DLI

• CIHI has provided Discharge Abstract Database (DAD) sample files to be part of the DLI collection, along with complete documentation, for a pilot project ending March 31st, 2014

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Overview of the Discharge Abstract Database

(DAD)

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What is the DAD?

• The Discharge Abstract Database (DAD) captures administrative, clinical, and demographic information on hospital discharges (including deaths, sign-outs, and transfers). Some provinces and territories also use the DAD to capture day surgery.

• Currently, more than 3 million records are submitted to DAD annually.

• Data are received from all acute care facilities across Canada (except Quebec)

• Select chronic care, rehabilitation, and psychiatric facilities also submit data to DAD.

• Data from Quebec is submitted to CIHI directly by the ministère de la Santé et des Services sociaux (MSSS). This data is appended to the DAD to create the Hospital Morbidity Database (HMDB).

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DAD data elements - Groups

• Data elements are organized into the following groups:

• Abstract Identification

• Length of Stay

• Patient Demographics

• Admission Data

• Discharge Data

• Patient Service Information

• Service Transfers

• Provider Information

• Diagnosis Information

• Intervention Information …continued on next slide

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DAD data elements - Groups

• Special Care Information

• Blood Information

• Reproductive Care Information

• Not all of this information is included in the DLI sample files

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DAD - DLI sample files

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Regarding DAD-DLI files

• DAD coverage for acute inpatient care is virtually complete for Canada, except Quebec (80% of all inpatient discharges in Canada)

• DAD data files for DLI include acute inpatient cases from all provinces/territories except Quebec and British Columbia

• Files were designed to maintain a balance between patient privacy and usefulness of data

• 10% sample ensures privacy, but reduces richness of data files

• Combining two years of data enhances richness

• Two DAD-DLI files: one with more clinical detail, one with more geographic detail

• Documentation accompany the data files

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Patient-oriented Approach

• Analysis potential is greater when the sequence of care for an individual can be followed over time

• The DAD-DLI files allow this

• Separate, non-overlapping 10% samples of persons were created for the ‘clinical’ and ‘geographic’ files

• Then, all discharge records belonging to these patients over a two-year period were included in the DAD-DLI files

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Longitudinal information

• Dates are not provided in the files (privacy)

• Temporality of events is provided by the number of days as of a reference date (day zero)

• This reference date is specific to each person in the data files

• The reference dates are between March 1, 2009 and March 31, 2009, and are randomly assigned to the selected individuals

• All discharges in the 730-day period starting with the reference day are included in the files

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Contents of files

• To protect patient privacy, there is less clinical detail in the geographic file, and vice versa

• Also, some variables are made available in ‘collapsed’ form:

– Age

– Length of stay

– Newborn weight

– Gestation weeks at delivery

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Common data elements

• Person identifier (meaningless except to identify discharge records for the same person within the files)

• Facility province (territories are combined)

• Discharge day (relative to reference day)

• Admission day (relative to reference day), calculated using the collapsed total length of stay

• Gender

• Age group (newborn, less than 1 year, 1-7, 8-12, 13-17, 18-24, 25-29, 30-34, … 75-79, 80+ years)

• Admission/discharge variables

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Clinical detail file

• Clinical details:

– Diagnoses(1-25): code(ICD-10-CA) and type

– Interventions(1-20): code(CCI), status, location, anaesthetic

– Special care unit visits(1-6): type/number and hours

• Length of stay: seven categories (0, 1, 2, 3, 4-5, 6-9, 10+ days)

• Newborn weights: six categories (under 750, 750-999, 1000-1499, 1500-1999, 2000-2499, 2500+ grams)

• Gestation weeks at delivery: four categories (under 32, 32-33, 34-36, 37+ weeks)

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Geographic detail file

• Health Region

• Case Mix variables:

– Major Clinical Category (MCC)

– Case Mix Group (CMG)

– CMG age category

– Resource Intensity Weight (RIW)

– Expected Length Of Stay (ELOS)

– RIW Atypical code

– Resource Intensity Level

• Length of Stay: three categories (0, 1-2, 3+ days)

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DAD-DLI file formats

• ASCII with fixed width columns (.dat)

• SPSS (.sav)

• Total file size: 340 MB (.dat), 190 MB (.sav)

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DAD Documentation for DLI

• File specifications containing methodological notes

• Record layouts with field description and values

• Data quality documentation

• DAD Abstracting Manual

• International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Canada (ICD-10-CA)

• Canadian Classification of Health Interventions (CCI)

• CMG+ Directory 2011

• Available in both English and French

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Example: Using the DAD-DLI sample files

• Objective: – To examine new cases of acute myocardial infarction (AMI)

in patients age 18 and older in the clinical file

• Inclusion criteria:– AMI present on admission

ICD-10-CA: I21, I22 coded as diagnosis type 1 (Pre-Admit Comorbidity)

– Age group at discharge: 18-24 years and above

• Exclusion criteria:– Difference between relative discharge day is 28 days or less

for AMI hospitalizations belonging to the same patient

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Example (continued)

• Can also look at the procedures performed on patients with diagnosis of AMI via the intervention or CCI code fields

• This example could be applied with the geographic file via CMGs containing diagnosis and/or procedures related to heart attacks

• Other components in geographic file such as indicators of resource consumption (RIW and ELOS) provide additional information on the study population

• Both files will help academic researchers to understand the structure of the DAD, and to determine/refine a specific research topic for their thesis

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Key uses of the DAD-DLI sample files

• Researchers can become familiar with the structure and content of DAD data

• Researchers can explore inter-relationships among DAD data elements (e.g. diagnoses and interventions, Case Mix information)

• Researchers can perform preliminary analyses and data mining

Provides researchers with an opportunity to work with the DAD data and clarify data requirements before making a formal data request to CIHI

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For your information – Other ways of accessing data from CIHI

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Option for accessing data from CIHI

• CIHI website

– Quick Stats and Analytic Reports

– Free, pre-formatted, aggregate-level data

• Customized data request

– Aggregate-level

– Record-level

– CIHI has a Graduate Student Data Access Program

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Graduate Student Data Access Program

• CIHI provides data to qualifying graduate students at no cost through the GSDAP (please visit www.CIHI.ca)

• Objectives:

– To build the capacity of graduate students to undertake health service research; and

– To increase awareness of CIHI and CIHI’s data holdings, and the importance of data quality and privacy, as graduate students pursue health services research careers

• Criteria:

– Data are to be used by the student to fulfill graduate requirements

– The research project was reviewed by a research ethics board

– The research project will support CIHI’s mandate

Aggregate

• Groups or summaries of data

• E.g. Counts, means, median

• Data table

• Small cell sizes may be suppressed (counts<5)

Customized requests

Person-level

• De-identified data, limited to meeting the project’s needs

• Each record refers to data from an individual, who may have more than one record in the database

• Format (SAS, comma-delimited)

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Process of accessing data from CIHI

• Step 1: Determining your own data requirement

– Are the data required available on CIHI website

– If not, contact CIHI for a customized data request

• Step 2: Your first contact with CIHI

– Online Data Inquiry Form

• Step 3: Initial Assessment of data request by appropriate CIHI staff based on the requirements provided on the inquiry form

• Step 4: Further documentation (e.g., signed Request Form), Specifications approval, data extraction and verification, and data release

Note: all data from CIHI are released to the users as per CIHI Privacy Policy (available on CIHI website)

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Service standard for custom data requests

Nature of the request

Aggregate-level data Record-level data

Standard request 10 working days 20 working days

Complex request 20 working days 40 working days

Very complex To be negotiated with the client To be negotiated with the client

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For more information

• Please visit CIHI’s website at www.cihi.ca

• If you would like more information about CIHI or DAD, please contact us via DLI

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Any questions or comments?

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Thank you!