No. 06: Avoidable Mortality by Neighborhood Income in Canada: 25 Years After the Establishment of Universal Health Insurance

June 2008

Background

Universal health insurance is central to the Canadian identity, based on equity of access regardless of ability to pay. This paper seeks to elucidate the impact universal health insurance has had on avoidable mortality considered from the perspective of neighborhood income.

Objective

Taking into account neighborhood income differences, to measure the avoidable deaths amenable to medical care and public health over a 25-year period after the establishment of universal insurance for doctors and hospital services in Canada.

Methods

Census tract coded data for metropolitan areas were obtained from the Canadian Mortality Database and population censuses for the years 1971, 1986, 1991 and 1996. Under analysis were avoidable deaths due to ischaemic heart diseases and “other causes” that were amenable to either medical or public health interventions. Deaths amenable to medical care were those for which hospital or physician services are reasonably expected to prevent death. Deaths amenable to public health interventions were those for which such interventions are known to prevent the condition from occurring. Data on deaths were grouped by cause of death, by amenability of cause of death to intervention, by income, and by census tract of the resident.  Census tracts were ranked based on the percentage of population below the low-income cut-off, and then assigned into quintile groups in order of lowest to highest percentage of low-income residents.

Results

From 1971 to 1996, differences between the richest and poorest quintiles in age-standardised expected years of life lost amenable to medical care decreased 60% (p<0.001) in men and 78% (p<0.001) in women. Differences amenable to public health increased 0.7% (p=0.94) in men and 20% (p=0.55) in women. Deaths from ischemic heart diseases decreased 58% in men and 38% in women, and from other causes decreased 15% in men and 9% in women. Decreases in the age-standardised expected years of life lost for deaths amenable to medical care were significantly larger than for deaths amenable to public health or other causes, for both men and women (p<0.001).

Limitations

There is difficulty in assigning deaths to their avoidable causes. Also, although the study shows a considerable reduction in mortality gradients between the early 70’s when universal health care was established across Canada, and the mid 90’s, the reduction in mortality varied considerably between diseases. Inferring why this variability occurs is important, but not discussed in the paper.

Conclusion

Reductions in rates of deaths amenable to medical care made the largest contribution to narrowing mortality across socioeconomic gradients. Continuing disparities in mortality from causes amenable to public health suggest that public health initiatives have a potentially important, but as yet unrealized, role in further reducing mortality disparities in Canada.

Relevance

As politicians and interest groups debate support for universal publicly funded health systems, the evidence supports the perception that Medicare has had substantial impacts on reducing inequality among Canadians and reducing avoidable mortality.

Avoidable mortality by neighborhood income in Canada: 25 years after the establishment of universal health insurance. James, P., Wilkins, R., Detsky, A., Tugwell, P., Manuel, D. Journal of Epidemiology and Community Health. Vol. 61: 287-296 2007.

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