Trends in incidence and mortality from abdominal aortic aneurysm in New Zealand

Background: This study examined trends in abdominal aortic aneurysm (AAA) incidence and mortality in New Zealand (NZ) and compared these with mortality rates from England and Wales. Methods: Cause-specific death data were obtained from the NZ Ministry of Health, UK Office for National Statistics and National Archives (for England and Wales). The NZ National Minimum Data Set provided hospital discharge data from July 1994 to June 2009. Results: In 2005-2007 the age-standardized AAA mortality rate for men was 33.3 per cent less in NZ than in England and Wales (5.21 versus 7.81 per 100 000), whereas for women it was 9.8 per cent less (2.12 versus 2.35 per 100 000). Standardized mortality rates in NZ fell by 53.0 per cent for men and 34.1 per cent for women from 1991 to 2007. Between 1991-1992 and 2005-2007 the probability of a 65-year-old dying from an AAA fell by 28.2 per cent (from 1.872 to 1.344 per cent) in men, and by 6.3 per cent (from 0.837 to 0.784 per cent) in women. New AAA admission and hospital death rates in NZ peaked in 1999 for men, and in 2001 for women, and have since declined sharply. Hospital mortality ratios have also fallen, except for women with a ruptured aneurysm. Conclusion: The burden of AAA disease has been falling since at least 1991 in NZ, and since 1995 in England and Wales. Although survival appears to be improving, most of the reduction is due to lower disease incidence.