COVID outcomes
Hospitalisations for COVID-19 were identified by hospitalisations with the ICD-10-AM diagnosis code U07.1, Emergency use of U07.1 [COVID-19, virus identified], or U07.2, Emergency use of U07.2 [COVID-19, virus not identified] listed as a diagnosis code for the separation.
Deaths due to COVID-19 were identified by the ICD-10-AM code of U07.1, U07.2, or U10.9 as the underlying cause of death.
Standardised mortality ratio
Standardised mortality ratio (SMR) is a widely recognised measure used to account for differences in age structures when comparing death rates between populations. This method of standardisation can be used when analysing relatively rare events (i.e. where number of deaths is less than 25 for the analysed time period). The SMR has been used in the analysis of deaths due to COVID-19. It is used to control for the fact that the migrant populations have a younger age profile than the Australian population, and rates of COVID-19 deaths vary by age in both the study populations and the Australian population. The SMRs control for these differences, enabling comparisons of counts of COVID-19 deaths between the migrant groups and Australia without the confounding effect of differences in age. The SMR is calculated as the observed number of events (deaths due to COVID-19) in the study population divided by the number of events that would be expected if the study population had the same age and sex specific rates as the as the comparison population.
In the analysis of deaths due to COVID-19, 95% confidence intervals (CIs) are provided for each SMR to indicate the level of uncertainty around these estimates. Estimates produced using low numbers can be sensitive to small changes and will therefore have wide CIs. 95% CIs are provided within this report as they may account for the variation in absolute numbers of deaths due to COVID-19 (related to the small sample size). It is important to note that there are other sources of uncertainty, such as linkage error, that are not captured by the provided CIs.
Use of CIs is the simplest way to test for significant differences between migrant groups and Australian comparison groups. For the purpose of this report, differences are deemed to be statistically significant if CIs do not overlap with 1.0 in the case of an SMR.