Background
The Australian Government’s ‘’Closing the Gap’’ (CtG) program, introduced since 2008, aims to reduce health gaps among Indigenous Australians, with monitoring of progress being integral to the program.
Aim
We explored linked data methods to determine whether CtG has impacted on population-based acute stroke incidence in Western Australia.
Methods
First-ever strokes 2001-2013 were identified from linked hospital and mortality records. Prevalence-adjusted population denominators contributed to Indigenous and non-Indigenous age/sex-standardised rates (ASSRs). Two methods were used to measure trends: i) Joinpoint regression determined change-points in trends; ii) a period-stratified analysis (2001-2008; 2009-2013) with Poisson regression (sex/age-adjusted) estimated annual percentage changes. Analyses were stratified by Indigenous status, and annual Indigenous to non-Indigenous rate ratios (RRs) calculated by sex, metro-rural and broad age-group (20-54; 55-74).
Results
12,689 first-ever strokes (6.5% Indigenous) were identified. Indigenous annual ASSRs fluctuated but were consistently >3.5-times higher than non-Indigenous. Joinpoint analyses suggested significant incidence reductions during 2001-2013 for Indigenous females (-3.3%/year) and rural populations (-5.6%/year). The period-stratified analysis found no significant difference in Indigenous incidence for 2001-2008 versus 2009-2013. Non-Indigenous incidence overall was unchanged from 2001-2013 but increased in 20-54 years (+1.5%/year) and decreased in rural residents (-1.0%/year). Period-stratified analysis showed a significant reduction in Indigenous/non-Indigenous RRs in rural areas only.
Conclusion
Since 2001, Indigenous stroke incidence reduced among female and rural residents, but the overall gap has not. Given the complex determinants and long lead-time to stroke, evidence of impacts of CtG are likely to be delayed, with linked data offering a robust approach to monitoring.