Dataset
For this analysis an existing linked administrative dataset, Maternity1000 will be utilized for this component of the study (14). This dataset has identified all children born in Queensland (QLD), Australia, between 1st July 2012 to 30th June 2018 from the QLD Perinatal Data Collection. This has then been linked to the QLD Hospital Admitted Patient Data Collection, QLD Hospital Non-Admitted Patient Data Collection, QLD Emergency Department Data Collection, and Medicare Benefits Schedule and Pharmaceutical Benefits Scheme Claims Records between 1 July 2012 to 30th June 2019.
Culturally and linguistically diverse
As defined by the Australian Bureau of Statistics, CALD is defined as individuals born in countries that are not main-English speaking countries. These main-English speaking countries include Australia, Canada, Republic of Ireland, New Zealand, South Africa, United Kingdom (England, Scotland, Wales, Northern Ireland) and United States of America(15). CALD infants were defined by assessing the country of birth of mothers in the dataset, that had been prearranged into 30 countries or continental regions. Mothers who were not born in the main-English speaking countries described above, were included in the separate variable for CALD mothers. These countries and regions included Caribbean, central America, central Asia, central and west Africa, Chinese Asia, eastern Europe, Japan and the Koreas, mainland south-east Asia, maritime south-east Asia, Melanesia, Micronesia, middle east, north Africa, northern Europe, Polynesia, south America, south-eastern Europe, southern Asia, southern Europe, southern and east Africa, southern and eastern Europe, western Europe.
Separate populations were also created for south-east Asian mother’s, European mothers, African mothers, and all Asian mothers (excluding those previously identified as south-east Asian mothers). These were created in order to compare the results between varying CALD populations. South-east Asian mothers were defined as those mothers born in Melanesia, Micronesia, mainland south-east Asia, or maritime south-east Asia. The variable created for mothers born in Africa was comprised of mothers born in central and west Africa, north Africa, south and east Africa. South Africa was previously identified by the ABS as a main-English speaking country, and therefore would ideally be excluded from the initial CALD variable and the African mother’s variable that were created. However, for this particular dataset the country of birth data for both southern Africa and east Africa are grouped together. Therefore, south Africa was included as a non-main English-speaking country. The variable for mothers born in Europe was created by including mothers born in eastern Europe, northern Europe, south-eastern Europe, southern Europe, southern and eastern Europe, and western Europe. The variable for all Asian mothers (except those previously identified as south-east Asian mothers) included mothers born in southern Asia, Japan and the Koreas, Chinese Asia (including Mongolia) and central Asia.
Health events and outcomes
Health events and outcomes for the infants were divided into the following:
Birth outcomes:
- Special care nursery and/or NICU admission at birth;
- APGAR score<4 at 5 minutes;
- Low birthweight;
- Stillbirth or neonatal death.
Health access of low quality:
- potentially preventable hospitalisations: hospital admissions that could have been prevented by timely and adequate health care in the community (16) This was defined as any admission to hospital that could have been prevented by early health intervention through primary care and allied health services.
- emergency department presentations without admissions.
Onset of chronic health conditions before the age of 5:
- any hospital admission for infections, cancer, metabolic, mental health, gastrointestinal, neurological, musculoskeletal, cardiovascular, or renal as classified by ICD-10 code assigned to inpatient episodes as principal diagnosis; presentation for mental health outpatient care, based on diagnosis; access to autism, pervasive development disorder and disability service MBS items (item numbers 135, 137, 139, 82015, 82020, 82025, 82035).
Health service use
The number of health services accessed between birth and five years of age was classified into the following groups:
- GP Consultation;
- specialist consultations;
- diagnostic tests and imaging;
- pathology tests;
- ED presentations;
- In-patient episodes; and
- Hospital outpatient episodes.
The number of different types of health service utilized per year was presented annually from birth to five years.
Costs
Costs of health services assessed from birth to five years of age was classified into the following categories based on funder:
- public hospital funders,
- private health insurers,
- Medicare,
- the PBS, and
- individual out-of-pocket fees.
Total costs to all funders were calculated. Costs per year was from birth to five years were calculated. All costs are presented in 2020/2021 Australian dollars.
Analysis:
Initial descriptive statistics were utilized to characterize the difference in demographic and clinical characteristics of the mothers of CALD infants. To identify the differences in the likelihood of health events and outcomes, we created a series of multivariable logistic regression models to calculate the adjusted odds ratios for each health event or outcome from CALD infants born preterm, compared to those born full-term. Additionally, to identify a difference in the time to onset of health conditions for CALD and non-CALD infants, a survival analysis was performed to show the hazard ratio of onset of chronic health conditions. The difference in the number of health services accessed were analysed with Poisson regression models. The difference in number of services accessed were compared for CALD infants born preterm, compared to those born full-term. Finally, the differences in costs will be analysed with generalized linear models. A negative binomial distribution with a log link function was selected to account for the skewed distribution of the data All models were adjusted for mother’s age, smoking status at 20 weeks, parity, rurality, socioeconomic status, and calendar year. As a secondary analysis, the data was separated into groups based on CALD geographical location. These groups include south-east Asian (SEA), European, African, Central and South American, and other Asian (excluding SEA) mothers. Analysis for health service use, health events and outcomes, and costs to funders were also calculated for those infants of Australian-born mothers in the specified time period.