Hospital Management and Outcomes of Stroke in Indigenous Australians: Evidence from the 2009 Acute Care National Stroke Audit

Cluster randomized trials increasingly are being used in health services research and in primary care, yet the majority of these trials do not account appropriately for the clustering in their analysis. We review the main implications of adopting a cluster randomized design in primary care and highlight the practical application of appropriate analytical techniques. The application of different analytical techniques is demonstrated through the use of empirical data from a primary care-based case study. Inappropriate analysis of cluster trials can lead to the presentation of inaccurate results and hence potentially misleading conclusions. We have demonstrated that adjustment for clustering can be applied to real-life data and we encourage more routine adoption of appropriate analytical techniques.

International targets for reducing health inequalities, such as the Millennium Development Goals, are stated in terms of national targets. However, dramatic health differentials exist within countries, even developed ones. Studies indicate that the Indigenous population of Australia suffers a life expectancy disadvantage greater than differentials found in Indigenous populations of other developed countries. We re-examine recent national mortality levels and trends of Indigenous Australians. Analyses of Indigenous mortality are plagued by 'numerator-denominator bias', whereby reporting of Indigenous status differs in deaths (numerators) and population (denominators). We apply demographic evaluation methods developed to address such problems to data from the 1991, 1996 and 2001 censuses of Australia and to the death registration data for the period. The propensity of Australia's population to report Indigenous status increased between each census, particularly between 1991 and 1996, while recording of deaths as Indigenous increased sharply. Adjusted for bias, the Indigenous population had a life expectancy approximately 13 years below that of the non-Indigenous population, a 2-year greater disadvantage than recently estimated for the Maori in New Zealand. Indigenous mortality fell during the 1990s, but slightly more slowly than that of non-Indigenous Australians, leaving differentials slightly increased. Around the world Indigenous populations are estimated to suffer a mortality disadvantage compared with non-Indigenous populations. However, establishing the magnitude of and trend in the disadvantage is difficult because of bias. Using appropriate methods to adjust for bias, the Indigenous population of Australia is estimated to suffer a life expectancy shortfall of about 13 years, greater than similar gaps in other developed countries.