Avoidable mortality in New Zealand, 1981-97

To describe avoidable mortality in New Zealand, including trends and variations between groups by age, gender, ethnicity and degree of deprivation.

New Zealand Health Information Service mortality unit records, 1981 to 1997, were classified as 'avoidable' or 'unavoidable' based on a reassessment of ICD9 codes and an upper age limit of 75 years. 'Avoidable' causes of death were further subcategorised according to the level of intervention involved (primary, secondary or tertiary). Deaths were assigned a deprivation score using a Census-based small area deprivation index, the NZDep96. Mortality rates were age standardised by the direct method, with Segi's world population as the reference.

Avoidable mortality declined 38% from 1981 to 1997; unavoidable mortality declined only 9%. In 1996-97 almost 70% of deaths in the 0-74 age range were still considered to be potentially avoidable. Almost 80% of avoidable deaths occur in the 45-74 age group. These deaths are dominated by the emergence of chronic diseases such as ischaemic heart disease, diabetes and smoking-related cancers. In younger age groups, injury (including suicide) dominates avoidable mortality. Males experience a greater burden of avoidable mortality than females--a relative excess of 54% (approximately 2,000) in 1996-97. The gender difference is largely attributable to diseases and injuries amenable to primary prevention, with the largest single contribution coming from ischaemic heart disease. The ethnic gap in avoidable mortality remains wide: rates for Mäori and Pacific people were 2-2 1/2 times higher than European rates in 1996-97. Similar gradients are seen with deprivation.

Avoidable mortality analysis provides a useful tool for evidence-based health needs assessment and health policy development.