Universal Drug Coverage and Socioeconomic Disparities in Major Diabetes Outcomes
- Gillian L. Booth, MD, MSC1,5⇓,
- Phoebe Bishara, MD4,
- Lorraine L. Lipscombe, MD, MSC2,6,
- Baiju R. Shah, MD, PHD2,5,
- Denice S. Feig, MD, MSC2,5,
- Onil Bhattacharyya, MD, PHD1,7 and
- Arlene S. Bierman, MD, MS1,3,5,8
- 1Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada
- 2Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
- 3Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- 4Division of Endocrinology and Metabolism, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- 5Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Ontario, Canada
- 6Women’s College Research Institute, Women’s College Hospital, Toronto, Ontario, Canada
- 7Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada
- 8Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Ontario, Canada
- Corresponding author:
Gillian L. Booth, .
OBJECTIVE Due in large part to effective pharmacotherapy, mortality rates have fallen substantially among those with diabetes; however, trends have been less favorable among those of lower socioeconomic status (SES), leading to a widening gap in mortality between rich and poor. We examined whether income disparities in diabetes-related morbidity or mortality decline after age 65, in a setting where much of health care is publicly funded yet universal drug coverage starts only at age 65.
RESEARCH DESIGN AND METHODS We conducted a population-based retrospective cohort study using administrative health claims from Ontario, Canada. Adults with diabetes (N = 606,051) were followed from 1 April 2002 to 31 March 2008 for a composite outcome of death, nonfatal acute myocardial infarction (AMI), and nonfatal stroke. SES was based on neighborhood median household income levels from the 2001 Canadian Census.
RESULTS SES was a strong predictor of death, nonfatal AMI, or nonfatal stroke among those <65 years of age (adjusted hazard ratio [HR] 1.51 [95% CI 1.45–1.56]) and exerted a lesser effect among those ≥65 years of age (1.12 [1.09–1.14]; P < 0.0001 for interaction), after adjusting for age, sex, baseline cardiovascular disease (CVD), diabetes duration, comorbidity, and health care utilization. SES gradients were consistent for all groups <65 years of age. Similar findings were noted for 1-year post-AMI mortality (<65 years of age, 1.33 [1.09–1.63]; ≥65 years of age, 1.09 [1.01–1.18]).
CONCLUSIONS Observed SES differences in CVD burden diminish substantially after age 65 in our population with diabetes, which may be related to universal access to prescription drugs among seniors.
- Received February 22, 2012.
- Accepted May 28, 2012.
- © 2012 by the American Diabetes Association.
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