A new study has found that mortality declined by more than 30 per cent in patients with diabetes between 1995 and 2006 in Ontario. However, people from lower income neighbourhoods experienced a significantly smaller improvement compared to their counterparts from wealthier neighbourhoods. In fact, the research shows that the mortality ratio between those aged 30 to 64 in the lowest income group compared to the highest income group widened by more than 40 per cent.
"Our findings illustrate the widening impact of income on the health of diabetes patients even in a publicly-funded health system," says principal investigator Dr. Lorraine Lipscombe, a scientist at the Women's College Research Institute at Women's College Hospital 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."
The researchers identified three factors that may contribute to these findings:
- A rise in the complexity and cost of diabetes care and treatment over the last decade which has contributed to an overall improvement in survival, but can pose a financial burden.
- Differences in screening rates for diabetes across income groups, with greater screening and earlier diagnosis among wealthier populations.
- The changing ethnicity of Ontario's population during the study period, with a dramatic increase in immigration of ethnic groups that are more susceptible to diabetes and tend to have lower incomes.
In Ontario, for instance, the provincial health plan only covers the costs of medications and supplies for persons over 65-years-old or those with very low income. Consequently, younger and poorer diabetes patients who cannot access the drug benefit plan, may not benefit as much from advances in diabetes care compared to more affluent patients.
"Income is a well-known predictor of survival," adds Lipscombe. "Purchasing medications and supplies can be a significant barrier to effective care among patients who cannot afford them."
The study, to be published in the December 21 issue of CMAJ (Canadian Medical Association Journal), used health-care databases in Ontario to compare changes in mortality rates among adults with diabetes by neighbourhood income.
"Our findings show a troubling increase in the income-related mortality gap," concludes Lipscombe. "Further studies are needed to explore factors responsible for this rising difference in mortality between rich and poor diabetes patients. In the meantime, better allocation of resources is needed for our more vulnerable populations of diabetes patients."
The study was supported by funding from the National Diabetes Surveillance System from Ontario's Ministry of Health and Long-Term Care.
More detailed study findings are available on the ICES website at www.ices.on.ca
