TORONTO - While the overall death rate from diabetes has declined in Canada, those with lower incomes continue to have a higher mortality rate related to the disease than their wealthier counterparts, an Ontario study suggests.
Researchers found that deaths from the complications of diabetes declined by more than 30 per cent between 1995 and 2006 in Ontario. However, diabetics from lower-income neighbourhoods experienced a significantly smaller improvement than those from more upscale neighbourhoods.
The mortality rate fell by 33 per cent across all income groups, but higher income groups had a larger decline in diabetes-related deaths than the lowest income group (36 per cent versus 31 per cent).
In those aged 30 to 64, there was a more than 40 per cent widening gap in the mortality ratio between the poorest and richest groups of diabetics, the researchers report in this week's issue of the Canadian Medical Association Journal.
"Our findings illustrate the widening impact of income on the health of diabetes patients, even in a publicly funded health system," said principal investigator Dr. Lorraine Lipscombe of Women's College Hospital in Toronto and the Institute for Clinical Evaluative Sciences (ICES).
"Even in Canada, where much of health care is universally funded, income-based inequities in health and access to care remain."
Over the 11-year study period, the number of Ontarians aged 30 and older with diabetes rose 130 per cent. Death rates from the disease were significantly higher in men than in women and in people aged 65 and older, compared with younger people.
Globally, diabetes is associated with a two-fold increase in premature mortality, with most deaths occurring because of cardiovascular disease. Survival for people with diabetes has improved over the last 10 years, partly because of better diabetes care and a reduction in cardiovascular events like heart attacks and strokes.
"Our findings suggest that improvements in diabetes outcomes may be lagging in the poorer segments of the diabetic population," say the authors, who identified several factors that may contribute.
For one, diabetes management has become more complex and costly over the last decade. While treatment advances have contributed to improved survival overall, they can pose a financial burden for some diabetics.
In Ontario, for instance, the provincial health plan covers the costs of medications and supplies only for people over 65 or those with a very low income. Consequently, younger and poorer diabetics who are ineligible for the drug plan may not benefit as much from advances in care as more affluent patients.
"Income is a well-known predictor of survival," Lipscombe said in a release. "Purchasing medications and supplies can be a significant barrier to effective care among patients who cannot afford them."
Screening rates for diabetes also differ across income groups, with wealthier populations having greater access to screening, resulting in earlier diagnosis.
Changing demographics in Ontario, especially due to immigration, may also be a factor, the researchers say. Between 1996 and 2006, 37 per cent of immigrants to the province were South Asian, a group that has a high susceptibility to diabetes and cardiovascular complications. As well, new immigrants often have lower incomes than more established residents.
"Our study highlights the urgent need to address barriers to adequate diabetes care in low-income populations, to stem the rising burden of diabetes among poorer people," the authors write.