ILL-DEFINED CAUSES (R00-R99)
Ill-defined causes (R00-R99) accounted for 1,143 deaths registered in Australia in 2011. This represented 0.8% of all registered deaths.
Deaths due to Other ill-defined and unspecified cause of mortality (R99) accounted for 742 deaths, or 64.9% of all deaths due to Ill-defined causes. The number of deaths coded to Ill-defined causes may be affected by the number of open coronial cases remaining on National Coroners Information System (NCIS) at the end of the ABS processing period, as the majority of open cases for which no information was available at the end of processing have been coded to Other ill-defined and unspecified causes (R99). 2011 coroner certified deaths are subject to a revisions process, see Explanatory Notes 29-33 and Technical Note: Causes of Death Revisions, 2009 and 2010.
In 2011, there were 63 deaths whose cause was identified as Sudden Infant Death Syndrome (SIDS) (R95). In processing causes of death, the ABS will only code a death to SIDS if specifically mentioned on the death certificate. Open coronial cases could potentially include cases where the cause of death may be determined as SIDS when closed. For further information, see Explanatory Notes 56-67.
For the past 10 years, more males have died from SIDS than females. The gap narrowed substantially in 2011, with 32 male to 31 female deaths. The majority of these deaths occurred in the period between 28 days and 1 year of age, with SIDS identified as the underlying cause of death for 56 (88.9% of SIDS deaths) infant deaths in this age group.