Trends in chronic disease mortality in the Northern Territory Aboriginal population, 1997-2004: using underlying and multiple causes of death

Objective: To assess trends in chronic disease mortality in the Aboriginal population of the Northern Territory (NT), using both underlying and multiple causes of death. Method: Death registration data from 1997 to 2004, were used for the analysis of deaths from five chronic diseases; ischaemic heart disease (IHD), diabetes, chronic obstructive pulmonary disease (COPD), renal failure and stroke. Negative binomial regression models were used to estimate the average annual change in mortality rates for each of the five diseases. Chi squared tests were conducted to determine associations between the five diseases. Results: The five chronic diseases contributed to 49.3% of all Aboriginal deaths in the NT. The mortality rate ratio of NT Aboriginal to all Australian death rates from each of the diseases ranged from 4.3 to 13.0, with the lowest rate ratio for stroke and highest for diabetes. There were significant statistical associations between IHD, diabetes, renal failure and stroke. The mortality rates for diabetes, COPD and stroke declined at estimated annual rates for NT Aboriginal males of 3.6%, 1.0% and 11.7% and for Aboriginal females by 3.5%, 6.1% and 7.1% respectively. There were increases in mortality rates for Aboriginal males and females for IHD and a mixed result for renal failure. Conclusion: NT Aboriginal people experience high chronic disease mortality, however, mortality rates appear to be declining for diabetes, COPD and stroke. The impact of chronic disease on mortality is greater than previously reported by using a single underlying cause of death. The results highlight the importance of integrated chronic disease interventions.