TECHNICAL NOTE 1 CHANGES TO PERINATAL DEATH CODING
1 The Australian Bureau of Statistics introduced a program of improvements to its causes of death collection in 2014. This included the introduction of a new software system for coding causes of death, implementation of updates to the International Classification of Diseases 10th Revision (ICD-10) and a review of coding practices.
2 In Australia, neonatal deaths (deaths that occur within 28 completed days of birth) are reported on the Medical Certificate of Cause of Perinatal Death (MCCPD). The review highlighted that there was no internationally supported rule base in the ICD-10 for assigning an underlying cause to deaths reported on the MCCPD. Neonatal deaths for 2013, published in Causes of Death Australia, 2013 were not assigned an underlying cause of death. Instead, as an interim measure ‘main condition in infant’ replaced the underlying cause for neonatal deaths as the primary output.
3 Data users in Australia indicated their preference for the reporting of a single underlying cause of neonatal deaths. From a public health and policy perspective, understanding the condition which initiated the train of morbid events is far more valuable than a blanket output of Main Condition in Infant. The ABS understands the importance of fit for purpose information on causes of neonatal deaths.
4 Since the release of the 2013 publication, the ABS led a process, working with coding specialists both internationally and nationally, to derive a coding method which could assign an underlying cause to deaths certified using the MCCPD. This has resulted in a new coding method for neonatal deaths which has been implemented by the ABS.
CHANGES TO THE CODING PROCESS
5 The MCCPD only allows certifiers to report a 'main condition in infant', 'main condition in mother' and other conditions. The MCCPD does not allow a certifier to provide a sequence which is required to identify an underlying cause of death. Deaths which occur 28 days or more after birth are reported on the Medical Certificate of Cause of Death (MCCD) which is specifically designed around providing a sequence for deriving an underlying cause.
6 Volume 2 of the ICD-10 provides guidelines for the production and tabulation of mortality data. Instructions in Volume 2 of the ICD-10 relating to use of the MCCPD note that where a single cause of death is required to be reported in tabulated outputs, the 'main condition in infant' should be used.
7 Up to and including the 2012 reference year the ABS had derived and reported an underlying cause for neonatal deaths. The derivation of this underlying cause was based on rules developed by the ABS which assumed causal links between different conditions reported on the perinatal certificate. As this set of rules was not based on the ICD guidelines the decision was taken in 2014 to cease this process beginning with data for the 2013 reference year until a supported method could be implemented. An interim method was used to process 2013 perinatal causes of death, with only ‘main condition in fetus/infant’ and ‘main condition in mother’ being output, and no underlying cause identified.
8 Since the release of the 2013 publication, the ABS has implemented a new, internationally supported method for deriving an underlying cause of neonatal death.
9 The new coding method adopted for the 2014 reference year utilises existing infrastructure including the ICD-10 perinatal rules, Iris and the ICD-10 Acme decision tables used for general death coding, to identify a causal sequence on a MCCPD, and therefore a single underlying cause of death. This aligns the output for neonatal deaths to deaths of the general population, which are certified using the MCCD.
10 The ABS will continue to work with key stakeholders to understand specific coding and reporting requirements for perinatal deaths.
CHANGES TO TIME SERIES DATA WITHIN UNDERLYING CAUSE OF DEATH TABLES
11 Information on neonatal deaths presented in tabulations up to 2012 are based upon the method previously used by the ABS to derive an underlying cause of death. The new internationally supported method has been applied to tabulations for the 2014 reference period and retrospectively to the 2013 reference period neonatal dataset. Any time series comparisons must take into consideration the difference in method for underlying cause selection.