The impact of health care on mortality: time trends in avoidable mortality in Australia 1968-2001

Abstract

We investigate the extent to which health care has contributed to the decline in mortality rates in Australia over recent decades by examining trends in avoidable mortality between 1968 and 2001. Avoidable mortality refers to deaths from certain conditions that are considered to be largely avoidable given timely and effective health care. Using unit record mortality data, we classified deaths into three avoidable categories: conditions amenable to medical care (‘medical care indicators’ (MCI)), conditions responsive to health policy but that are considered to lack effective treatment once the condition has developed (‘health policy indicators’ (HPI)), and ischaemic heart disease(IHD). ‘Nonavoidable’ deaths included the remaining causes of death. Our findings suggest that the Australian health care system has made substantial contributions to the reduction in mortality over the past three decades. This is shown in the steady decline in avoidable mortality rates with slower declines in nonavoidable mortality rates. Between 1968 and 2001, total avoidable death rates fell around 70% (68.4% in females, 72.2% in males) and nonavoidable rates fell around 34% (34.6% in females, 33.2% in males). Using Poisson regression, the annual declines in avoidable mortality rates were as follows (95% CIs in parentheses): 3.47% (3.44-3.50%) in females and 3.89% (3.86-3.91%) in males. For nonavoidable mortality rates, the annual declines were 1.09% (1.05-1.13%) in females and 0.95% (0.92-0.98%) in males. The trends in avoidable mortality in Australia were similar to those of other European countries, with Australia improving it’s ranking between 1980 and 1998, performing particularly well with respect to MCI. In females, declines in MCI death rates made the largest contribution to the decline in avoidable mortality rates (54%) with the IHD contribution being 45%. In males, reductions in IHD death rates made the largest contribution (57%), with the MCI contribution being 32%. For both sexes, most of this decline occurred in only a small number of the thirty-five MCI causes – cerebrovascular disease, cancer of the breast (females), cancer of the colon and rectum, perinatal deaths and pneumonia. Declines in HPI death rates made a negligible contribution in females (1%) and only a modest contribution in males (11%). While the observed declines in avoidable mortality rates may also reflect changes in other factors that influence mortality such as environment and socioeconomic conditions, they are consistent with, and suggestive of, the health care system being an important determinant of health improvements in Australia in recent decades.