IDI Data Dictionary:
Chronic condition/significant health
event cohort
November 2015 edition
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Citation
Statistics New Zealand (2015). IDI Data Dictionary: Chronic condition/significant health
event cohort (November 2015 edition). Available from www.stats.govt.nz.
ISSN 2463-4212 (online)
Published in November 2015 by
Statistics New Zealand
Tatauranga Aotearoa
Wellington, New Zealand
Contact
Statistics New Zealand Information Centre: info@stats.govt.nz
Phone toll-free 0508 525 525
Phone international +64 4 931 4600
www.stats.govt.nz
Contents
1 Purpose of this data dictionary ....................................................................................4
Background ......................................................................................................................4
List of datasets.................................................................................................................4
2 About the chronic condition/significant health event cohort ...................................5
Overview ..........................................................................................................................5
Coverage .........................................................................................................................5
Methodology ....................................................................................................................5
Quality information ...........................................................................................................6
Privacy, security, or confidentiality issues .......................................................................6
3 Data dictionary for the chronic condition/significant health event cohort .............7
Dataset description ..........................................................................................................7
Summary table ...............................................................................................................12
Detailed information .......................................................................................................12
3
1 Purpose of this data dictionary
IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015
edition) documents the content of this dataset the Ministry of Health (MOH) provides to
Statistics New Zealand to use in the Integrated Data Infrastructure (IDI).
This dictionary gives information on the variables contained in the dataset for the start
and end dates provided under the relevant chronic condition/significant health event –
including technical information and descriptions.
Use this data dictionary if you are interested in understanding and accessing chronic
condition/significant health event cohort information in the IDI for your research.
Background
The MOH seeks to improve, promote and protect the health of New Zealanders through:
its sector leadership of New Zealand’s health and disability system; advising the Minister
of Health, and government as a whole, on health issues; directly purchasing a range of
important national health and disability support services; providing health sector
information and payment services for the benefit of all New Zealanders.
The objectives of the MOH’s data and metadata are to: measure and describe the
information available within the National Collections; promote uniformity, availability and
consistency across the National Collections; support the use of nationally agreed
protocols and standards wherever possible; promote national standard definitions and
make them available to users.
List of datasets
Chronic condition/significant health event cohort
4
2 About the chronic condition/significant health event
cohort
Overview
This dataset contains information about healthcare users in the population cohort who
have been diagnosed with one or more of eight chronic conditions/significant health
events identified using a variety of sources.
Information about three of these (coronary heart disease [CHD], gout, chronic obstructive
pulmonary disease [COPD]) have been provided from the Health Tracker. The Health
Tracker links data from a variety of national collections to create a series of indicators.
This dataset is owned and maintained by Health and Disability Intelligence (HDI), Policy
Business Unit, MOH.
Information about diabetes has been provided from the Virtual Diabetes Register (VDR).
The VDR is maintained by Analytical Services, National Collections and Reporting, MOH.
Healthcare users with a cancer diagnosis have been provided from the New Zealand
Cancer Registry (NZCR). This national health collection contains all cancer registrations
from 1948 onwards. More information about the NZCR can be found in the cancer
registrations data dictionary.
Healthcare users with the remaining three conditions (traumatic brain injury, stroke and
acute myocardial infarction) have been identified using data from the National Minimum
Data Set (NMDS). This national health collection contains all publicly funded
hospitalisations from 1988 onwards. More information about NMDS can be found in the
publicly funded hospital discharges data dictionary.
Coverage
Reference period start and end date: Information about the reference period start and
end date have been provided under the relevant chronic condition/significant health
event.
Geographic coverage: New Zealand
Target population: Healthcare users
Observed population: People who were reported as having one or more of the eight
chronic conditions/significant health events identified below. For the tracker
conditions/events only people within the core population (New Zealand residents who
have had health system contact in two or more quarters in the relevant twelve month
period) have been included.
Methodology
Type of data: Administrative
Data collector: MOH
Mode of data collection: The Health Tracker, Virtual Diabetes Register, New Zealand
Cancer Registry, and the National Minimum Dataset.
Frequency of data collection: Various
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
Quality information
Information about the quality of the information can be found in the dataset description
section.
Privacy, security, or confidentiality issues
The chronic condition/significant health event cohort table that is accessible to
researchers does not contain any name or address information to identify an individual.
All researchers who have access to the chronic condition/significant health event cohort
data have had their research proposals assessed using Statistics NZ’s microdata access
protocols and only approved researchers who have been granted access by Statistics NZ
and the Ministry of Health may view the chronic condition/significant health event cohort
data.
Read Statistics NZ’s microdata access protocols.
All outputs produced from chronic condition/significant health event cohort data must be
aggregated and counts suppressed if the underlying unrounded count is fewer than six.
6
3 Data dictionary for the chronic condition/significant
health event cohort
Dataset description
Contents of dataset: This dataset contains information about the healthcare users in
the population cohort who meet the indicator requirements for one of more of eight
chronic conditions/significant health events. The conditions used to identify cohort
members with these chronic conditions/significant health events are below.
Definitions:
1. CHD prevalence and incidence
The following definition, data source section and part of the CHD dates section were
written by Michelle Liu, HDI.
Definition
A healthcare user is counted as having CHD if they meet any one of the following
conditions:
1. National Minimum Dataset (NMDS) diagnosis codes:
ICD-9-CMA: 410-414, V4581, V4582
ICD-10-AM: I20-I25, Z951, Z955
2. NMDS procedure codes:
ICD-10-AM: 3530400, 3530500, 3531000, 3531001, 3531002, 3849700, 3849701,
3849702, 3849703, 3849704, 3849705, 3849706, 3849707, 3850000, 3850001,
3850002, 3850003, 3850004, 3850300, 3850301, 3850302, 3850303, 3850304,
3863700, 9020100, 9020101, 9020102, 9020103
ICD-9-CMA: 3601, 3602, 3603, 3604, 3605, 3606, 3607, 3610, 3611, 3612, 3613,
3614, 3615, 3616
3. Two or more dispensings of any of the following drugs, in the most recent 12 month
period:
1577 - Glyceryl trinitrate
2377 - Isosorbide dinitrate
2836 - Isosorbide mononitrate
1272 - Nicorandil
1949 - Perhexiline maleate
Data source used
 National Minimum Dataset – both publicly and privately funded hospital discharge
information
 Pharmaceutical Claims
 Tracker core population - The core dataset contains the NHIs of resident New
Zealanders for a particular 12 month period (generally from 1 July to 30 June)
CHD incident date and most recent incident dates
For CHD conditions, the fields entitled ‘first incident date’ and ‘most recent incident date’
don’t always represent the first and most recent incident dates. These fields are
calculated in a different way to other conditions:
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
 The ‘first incident date’ field represents the first date the person received a ‘CHD
diagnosis’ (listed above) in NMDS. This may not necessarily be the first incident
date as a person may have been dispensed a ‘CHD pharmaceutical’ (listed above)
before this date.
 The ‘most recent date’ field represents the first date the person received a ‘CHD
diagnosis’ in NMDS or the first dispensing of a ‘CHD pharmaceutical’. This
approach is more comprehensive but uses pharmaceutical data which is less
specific and reliable than diagnostic codes. Furthermore the date is unlikely to
represent the most recent incident date as the person may have received a “CHD
diagnosis/pharmaceutical” after this date.
According to Dr. Terry Quirke (National Health Committee) the first option is more robust
and therefore we recommend that you use the ‘first incident date’ field. However option
two is also available if option two is preferred.
Completeness
The CHD data is complete between 01/01/2007 and 30/06/2013. It has been provided
from 1985 onwards (the record from 1955 is likely an error). Please use records with an
incident date before 2007 with caution.
2. Gout
The definition and data source section was written by Michelle Liu, HDI.
Definition
A healthcare user is counted as having showed an indication of gout if they have one of
the codes specified below (from any data collection) within the time period searched (e.g.
12 month or lifetime):
National Minimum Dataset (NMDS) codes:
ICD-9-CMA: 274
ICD-10-AM: M10
Mental Health Information National Collection (MHINC up to June 2008) / Programme for
the Integration of Mental Health Data (PRIMHD from July 2008) codes:
ICD 9-CMA, and ICD-10-AM diagnosis codes as for NMDS
Pharmaceutical Collection:
1341 – Colchicine
1026 - Allopurinol*
*Dispensing of Allopurinol alone is only taken as an indication of gout if there is no
diagnosis of malignant neoplasm of lymphoid, haematopoietic and related tissues
(ICD-10-AM C81-C96) recorded in either the Cancer registry or in the publicly
funded hospitalisations in the NMDS in the 24 months before the period end date.
Data source used
 National minimum dataset – both publicly and privately funded
 Pharmaceutical Claims
 MHINC / PRIMHD
 Tracker core population - The core dataset contains the NHIs of resident New
Zealanders for a particular 12 month period (generally from 30 June – 1 July).
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
Completeness
Gout date is complete between 01/01/2007 and 31/12/2011. Records with an incident
date before 2007 are incomplete and should be used with caution. Furthermore records
from 2012 should also be used with caution. Healthcare users diagnosed with specific
cancers should have been excluded from the 2012 output but weren’t because of cancer
data availability at the time of extraction.
3. Chronic Obstructive Pulmonary Disease (COPD)
A healthcare user is counted as having showed an indication of COPD if they have one of
the codes specified below (from any data collection) within the time period searched (e.g.
12 month or lifetime):
National Minimum Dataset (NMDS) codes:
ICD-9-CMA:
490 (Bronchitis, not specified as acute or chronic)
4910 (Simple chronic bronchitis)
4911 (Mucopurulent chronic bronchitis)
49120 (Obstructive chronic bronchitis without mention of acute exacerbation)
49121 (Obstructive chronic bronchitis with acute exacerbation)
4918 (Other chronic bronchitis)
4919 (Unspecified chronic bronchitis)
4920 (Emphysematous bleb)
4928 (Other emphysema)
496 (Chronic airway obstruction, not elsewhere classified)
ICD-10-AM:
J40 (Bronchitis, not specified as acute or chronic)
J410 (Simple chronic bronchitis)
J411 (Mucopurulent chronic bronchitis)
J418 (Mixed simple and mucopurulent chronic bronchitis)
J42 (Unspecified chronic bronchitis)
J430 (MacLeod's syndrome)
J431 (Panlobular emphysema)
J432 (Centrilobular emphysema)
J438 (Other emphysema)
J439 (Emphysema, unspecified)
J440 (Chronic obstructive pulmonary disease with acute lower respiratory
infection)
J441 (Chronic obstructive pulmonary disease with acute exacerbation,
unspecified)
J448 (Other specified chronic obstructive pulmonary disease)
J449 (Chronic obstructive pulmonary disease, unspecified)
Mental Health Information National Collection (MHINC up to June 2008) / Programme for
the Integration of Mental Health Data (PRIMHD from July 2008) codes:
ICD-9-CMA and ICD-10-AM diagnosis codes as for NMDS
Pharmaceutical Chemical IDs:
1492 - Ipratroprium Bromide, excluding formulation IDs 5 and 6.
6311 - Salbutamol with Ipratroprium Bromide
3805 - Tiotroprium Bromide
Only if no previous diagnosis of asthma:
1056 - Aminophylline
1580 - Theophylline
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
Data source used
National minimum dataset 1988 onwards –publicly funded hospital discharge information
Private hospital discharge (2000–2010)
Pharmaceutical Claims (2001 onwards)
MHINC (1 Jul 2001– 30 Jun 2008)
PRIMHD (1 Jul 2008 – 24 Jun 2014)
Tracker core population - The core dataset contains the NHIs of resident New Zealanders
for a particular 12 month period (generally from 30 June – 1 July)
Completeness/coding changes
COPD data is complete between 01/01/2007 and 31/12/2012. Records with an incident
date before 2007 are incomplete and should be used with caution.
4. Diabetes
Part of this section was adapted from VDR documentation created by Emmanuel Jo and
Paul Drury. See the MOH website for more information about the VDR.
Definition
The VDR counts healthcare users who had:
1. Diabetes coded in hospital admissions from Jul 1999 to Dec 2013. (NMDS). Note:
Admissions with a code for gestational diabetes are not included.
National Minimum Dataset (NMDS) diagnosis codes (ICD-10-AM version 1)
E10 - Type 1 DM
E11 - TYPE 2 DM
E13 - Other specified DM
E14 - Unspecified DM
O240 - Pre-existing diabetes mellitus, Type 1, in pregnancy
O241 - Pre-existing diabetes mellitus, Type 2, in pregnancy
O242 - Pre-existing diabetes mellitus, other specified type, in
O243 - Pre-existing diabetes mellitus, unspecified, in pregnancy
2. Diabetes “education and management” (NNPAC code: M20006) attendance Jul
2002 to Dec 2013 excluding 2003/04 data for Northland DHB (because of a data
quality problem) (National Non-Admitted Patient Collection (NNPAC) and Personal
Health Non Case Weight (PHNCW).
3. Diabetes retinal (fundus) screening Jul 2002 to Dec 2013 (NNPAC and PHNCW).
This includes NNPAC code M20007.
4. Insulin or oral hypoglycaemic agents dispensed on 2 or more occasions between
Jan 2012 and Dec 2013 (excluding women aged 12-45 who may have only been
dispensed Metformin AND do not meet any of the other criteria). Note: This is
intended to exclude women age 12-45 whom may have polycystic ovary syndrome
treated with metformin.
Chemical IDs:
1192 - Insulin lispro
1570 - Glucagon hydrochloride
1648 - Insulin Neutral
1649 - Insulin isophane
1655 - Insulin zinc suspension
3783 - Insulin aspart
3857 - Insulin glargine
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
6300 - Insulin isophane with insulin neutral
1068 - Chlorpropamide
1247 - Acarbose
1567 - Glibenclamide
1568 - Gliclazide
1569 - Glipizide
2276 - Tolazamide
2277 - Tolbutamide
3739 - Rosiglitazone
3800 - Pioglitazone
1794 - Metformin hydrochloride
5. Healthcare users who attended diabetes specialist clinics / endocrinology clinics
between Jul 2002 and Dec 2013 who also meet one of the other criteria. This
includes NNPAC codes M20004 and M20005.
6. Healthcare users who have 4 or more HBA1c lab tests (lab test code BG2)
between Jan 2012 and Dec 2013. Note: Healthcare users with multiple HBA1c
tests are not counted unless they also meet another listed condition.
Completeness and coding change
Diabetes data is complete from 2005 onwards. Records with incident dates before 2005
are incomplete and should be used with caution.
In 2012 the coding of diabetes mellitus when it is mentioned in a healthcare user’s clinical
notes was reintroduced. Coding of diabetes mellitus was common practice up into
2008/09 with the introduction of ICD10-AM-VI. As shown in the table below this change
has significant impact on the number of discharges that contained a ‘diabetes diagnosis’.
Number of discharges that contain any diagnosis of E10-E14, 1 July 2004 to 30
June 2014
Financial
year
Diabetes coded
as additional
diagnoses (Y/N)
2004/05
Y
2005/06
Y
2006/07
Y
2007/08
Y
2008/09
N
2009/10
N
2010/11
N
2011/12
N
2012/13
Y
2013/14
Y
Source: NMDS
Number of
discharges
61725
64638
69156
64953
41604
41850
42732
47631
100365
106620
Notes:
1.
2.
The table above is only an example and should only be used for the purposes of
illustrating the coding change as some codes were used to create the VDR were
left out of the query.
Auckland DHB did not implement the coding change and continued to code
diabetes throughout the whole period.
See the MOH website for more information on the coding change in the NMDS.
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
5. Cancer
Definition: where the healthcare user had a malignant (Site code = C00-C96 [from 1995
onwards] OR D45-D47 [from 2003 onwards]) cancer registration in the New Zealand
Cancer Registry with a date of diagnosis between 1995 and 2011.
6. Traumatic brain injury
Definition: where the healthcare user had a publicly funded discharge in NMDS between
1 Jan 1988 and 30 Jun 2001 with a primary diagnosis of 800-801.9, 803-804.9, 850-854
(ICD 9) or a hospital discharge in NMDS between 1 Jul 2001 and 31 Dec 2013 with a
primary diagnosis of S06 (ICD-10-AM-II)
7. Stroke
Definition: where the healthcare user had a publicly funded discharge in NMDS between
1 Jan 1988 and 30 Jun 2001 with a primary diagnosis of 430-432, 433.01, 433.11,
433.21, 433.31, 433.81, 433.91, 434.01, 434.11, 434.91, 436 (ICD 9) or a hospital
discharge in NMDS between 1 Jul 2001 and 31 Dec 2013 with a primary diagnosis of I60164 (ICD-10-AM-II).
8. Acute myocardial infarction
Definition: where the healthcare user had a publicly funded discharge in NMDS between
1 Jan 1988 and 30 Jun 2001 with a primary diagnosis of 410 (ICD 9) or a discharge
between 1 Jul 2001 and 31 Dec 2013 with a primary diagnosis of I21 (ICD-10-AM-II).
Type of file: txt
Summary table
IDI Variable name
Primary
key
Mandatory
Format
Classification
name
Variable name
snz_uid
Int
snz_moh_uid
Int
moh_chr_condition_text
varchar, 8
condition
moh_chr_fir_incidnt_date
date
first_incident_date
moh_chr_fir_incidnt_id_code
varchar, 10
first_incident_id
moh_chr_last_incidnt_date
date
last_incident_date
moh_chr_last_incidnt_id_code
varchar, 10
last_incident_id
moh_chr_collection_text
varchar, 14
collection
Detailed information
_______________________________________
IDI variable name: snz_uid
Definition: a global unique identifier created by Statistics NZ. There is a snz_uid for each
distinct identity in the IDI. This identifier is changed and reassigned each refresh.
Format: Integer
Name of classification:
Notes:
_______________________________________
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
IDI variable name: snz_moh_uid
Definition: a local unique identifier derived by Statistics NZ from the source agency’s
unique identifier(s). This identifier will remain the same for an identity across refreshes.
Where we receive more information during a subsequent refresh that indicates that two or
more identities represent the same identity, the identifier may change.
The snz_moh_uid represents a distinct identity in all of MoH tables in IDI.
Format: Integer
Name of classification:
Notes:
_______________________________________
IDI variable name: moh_chr_condition_text
Definition: The name of the chronic condition
Format: Varchar, 8
Name of classification:
Notes: This will be one of the 8 specified conditions: coronary heart disease, gout,
COPD, diabetes, traumatic brain injury, stroke, acute myocardial infarction and cancer
_______________________________________
IDI variable name: moh_chr_fir_incidnt_date
Definition: The first date the healthcare user was admitted/diagnosed with the
condition/event.
Format: Date
Name of classification:
Notes: The following field/source was used for each condition/event:
Cancer registration – date of diagnosis (NZCR)
Coronary heart disease – incident date from the coronary heart disease indicator in the
Health Tracker (see note)
Gout – incident date from the gout indicator in the Health Tracker
COPD – incident date from the COPD indicator in the Health Tracker
Traumatic brain injury – admission date (NMDS)
Stroke – admission date (NMDS)
Acute myocardial infarction – admission date (NMDS)
_______________________________________
IDI variable name: moh_chr_fir_incidnt_id_code
Definition: The relevant event/diagnosis identifier (if applicable) for the first incident date.
Format: varchar, 10
Name of classification:
Notes: The following field/source for each condition/event was used:
Cancer registration - event ID (cancer collection)
Diabetes - NA
Coronary heart disease - NA
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IDI Data Dictionary: Chronic condition/significant health event cohort (November 2015 edition)
Gout - NA
COPD - NA
Traumatic brain injury - event ID (NMDS)
Stroke - event ID (NMDS)
Acute myocardial infarction - event ID (NMDS)
_______________________________________
IDI variable name: moh_chr_last_incidnt_date
Definition: The most recent admission/diagnosis date for the condition/event.
Format: Date
Name of classification:
Notes: The following field/source was used for each condition/event:
Cancer registration - date of diagnosis (NZCR)
Diabetes – date of diagnosis (VDR)
Coronary heart disease – incident date (Health Tracker)
Gout – incident date (Health Tracker)
COPD – incident date (Health Tracker)
Traumatic brain injury - admission date (NMDS)
Stroke - admission date (NMDS)
Acute myocardial infarction - admission date (NMDS)
Note: The most recent incident date could potentially be the same as the first incident
date.
_______________________________________
IDI variable name: moh_chr_last_incidnt_id_code
Definition: The relevant event/diagnosis identifier (if applicable) for the most recent
incident date.
Format: varchar, 10
Name of classification:
Notes: The following field/source was used for each condition/event:
Cancer registration - event ID (NZCR)
Diabetes - NA
Coronary heart disease - NA
Gout - NA
COPD - NA
Traumatic brain injury - event ID (NMDS)
Stroke - event ID (NMDS)
Acute myocardial infarction - event ID (NMDS)
Note: The most recent incident identifier could potentially be the same as the first incident
identifier.
_______________________________________
IDI variable name: moh_chr_collection_text
Definition: The collection from which the condition/event was identified
Format: Varchar, 14
Name of classification:
Notes: Examples include: health tracker, cancer collection, NMDS
14