State of usual residence

Figure 2 shows the age adjusted rate of incidence of persisting SCI from traumatic causes by state of usual residence. No rate was shown for the Northern Territory due to the non-reporting of injury dates for some cases, uncertainty about the reliability of data on a number of the remaining cases, and a low case count. The incidence rate for the ACT was not reported due to a low case count. The reported incidence rate for New South Wales was an estimate which included the 14 cases whose registration information was missing and whose age distribution was matched to that of the nationally reported cases.

Figure 2: Incidence of persisting SCI from traumatic causes by State of residency, Australia 1997/98 (age adjusted rates)

• It was evident from the 95% confidence intervals on the rates, based on the Poisson distribution, that Western Australia was the only State that had a rate significantly above the national incidence rate in 1997/98.

• The Western Australian rate for 1997/98 (26.7 per million of population) was double the rate for that State during 1996/97 (13.3 per million of population). Assessment of the 95% confidence intervals on these rates, based on the Poisson distribution, demonstrated that this difference was statistically significant. The increase in the case count (from 23 in 1996/97 to 47 in 1997/98) represents the potential for a substantial increase in the cost of SCI in that State.

• The Western Australian rate was significantly higher than the rates of New South Wales, Victoria and Queensland during 1997/98. No other State differences were significant. The lowest rate of SCI occurred in Victoria.

• The incidence rate of SCI in South Australia increased steadily over the last three years (11.6 per million of population in 1995/96, 15.3 per million of population in 1996/97, 20.8 per million of population in 1997/98). State trends will be assessed in detail once complete data is registered for all States for the period 1991 to mid-1995.