Completeness and quality of recording of country of birth in NSW administrative datasets

1
Completeness and quality of recording of country
of birth in NSW administrative datasets

• Sanja Lujic
• Louisa Jorm
• School of Medicine

2
Background

• Aims
• To explore patterns of country of birth (COB)
  recording in NSW administrative datasets
• Completeness of recording of COB
• Quality of recording consistency
• Value of using data linkage in increasing
  enumeration

3
Methods data sources

• NSW resident records only
• 1 July 2000 to 30 June 2006
• Admitted Patient Data Collection (APDC)
• Emergency Data Collection (ED)
• ABS mortality dataset (ABS deaths)

4
Methods

• Linkage done by the Centre for Health Record
  Linkage (CHeReL)
• Analysis done on de-identified linked dataset
  containing records for persons who
• Presented to an ED for a mental-health related
  diagnosis, OR
• Had at least one hospital stay for a
  mental-health related diagnosis, OR
• Died from mental health-related cause

5
Data linkage
APDC
1,230,074 records 502,302 persons
6
Data linkage
ED
270,447 records 164,536 persons
7
Data linkage
16,773 records 16,726 persons
ABS deaths
8
Persons 2000/01 2005/06 597,276
APDC
ED
82,672 (13.8)
417,885 (70)
79,993 (13.4)
1,714
157
31
14,824 (2.5)
ABS deaths
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Results - completeness
Dataset Records Records Persons Persons Persons
Dataset N missing N missing missing
APDC 1,230,074 2.2 502,302 4.0 2.0
ED 270,447 36.4 164,536 40.5 31.8
ABS death 16,773 14.7 16,726 14.7 -
All 1,517,294 8.5 597,276 14.9 6.9
Missing COB on at least 1 record Missing
COB on all records for a person (within the
dataset) Missing COB on all records across
datasets
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Results APDC
Number of COB per person Number of records per person Number of records per person Number of records per person Number of records per person
Number of COB per person 1 2 3 Total ()
1 297,384 94,199 102,507 494,090 (98.4)
2 2,089 5,685 7,774 (1.5)
3 438 438 (0.1)
Total 297,384 96,288 108,630 502,302
Excluding missing/unknown
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Results - APDC

• Example of multiple COB

Person Sequence Country of birth Number of records
1 1 Australia 1
1 2 Former Yugoslavia (NOD) 2
1 3 Macedonia 3
1 4 Former Yugoslavia (other than Croatia and Slovenia) 2
2 1 Australia 1
2 2 NZ 2
2 3 Italy 2
2 4 Chile 1
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Results APDC

• 2 Countries of birth
• 75.0 of combinations were Australia other
  country of birth
• Most common combinations
• Australia England (24.8)
• Australia NZ (9.1)
• Australia Scotland (4.1)
• Australia Italy (2.4)

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Results ED
Number of COB per person Number of records per person Number of records per person Number of records per person Number of records per person
Number of COB per person 1 2 3 Total ()
1 126,479 19,990 17,011 163,480 (99.4)
2 317 691 1,008 (0.6)
3 48 48 (0.0)
Total 126,479 20,307 17,750 164,536 (100)
Excluding missing/unknown
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Results ED

• 2 Countries of birth
• 80.7 of combinations were Australia other
  country of birth
• Most common combinations
• Australia England (20.5)
• Australia NZ (10.4)
• Australia Scotland (3.9)
• Australia Ireland (3.5)

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? Enumeration by linkage - Persons
Bars show number of overseas persons show
proportion of overseas persons in the dataset
16
? Enumeration by linkage - Persons
? 0.6
? 0.5
? 29.3
of persons born overseas
?
Relative increase
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Sample analysis
COB assigned from the Index admission
Disorder Australian born Australian born Australian born Australian born Overseas born Overseas born Overseas born Overseas born
Disorder No. persons Mean age Died Died No. persons Mean age Died Died
Disorder No. persons Mean age No. No. persons Mean age No.
Schizophrenia delusional disorders 20,165 38.0 160 0.79 5,691 43.5 47 0.83
Dementia 3,228 78.5 172 5.33 972 78.4 52 5.35
Mood disorders 37,034 43.1 266 0.72 7,976 49.7 64 0.8
Total 186,974 40.4 1,014 0.54 44,085 47.7 274 0.62
At first admission for a disorder
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Sample analysis
COB accumulated across time data set
Disorder Australian born Australian born Australian born Australian born Overseas born Overseas born Overseas born Overseas born
Disorder No. persons Mean age Died Died No. persons Mean age Died Died
Disorder No. persons Mean age No. No. persons Mean age No.
Schizophrenia delusional disorders 20,214 37.9 161 0.80 6,626 43.0 62 0.94
Dementia 3,214 78.6 171 5.32 1,037 78.4 57 5.50
Mood disorders 36,704 43.0 257 0.70 9,053 49.4 88 0.97
Total 187,002 40.4 991 0.53 47,386 47.7 362 0.76
At first admission for a disorder
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Sample analysis ED data
Condition COB at index admission COB at index admission COB at index admission COB accumulated across datasets and time COB accumulated across datasets and time COB accumulated across datasets and time
Condition Australia Overseas Missing Australia Overseas Missing
Schizophrenia 53.5 13.6 33.0 63.4 18.0 18.5
Dementia 46.8 17.2 36.0 56.2 23.9 19.9
Mood disorders 57.5 11.7 30.8 73.9 18.9 7.1
Total 53.4 13.6 33.0 63.2 18.3 18.5
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Limitations

• Only MH-related admissions/deaths studied
• How would this differ if we used other
  conditions?
• Time span relatively short
• How complete is COB recording pre 2000?

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Conclusions

• COB recording in admitted data is more complete
  than ED or death data
• COB recording is consistent within datasets
• Linkage could improve completeness of
• COB in ED data
• COB in mortality data - but only for conditions
  where hospitalisation before death is likely