Universal drug coverage and socioeconomic disparities in major diabetes outcomes.
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.


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.
Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto, Ontario, Canada. boothg@smh.ca
Gillian L
GL
Booth
Phoebe
P
Bishara
Lorraine L
LL
Lipscombe
Baiju R
BR
Shah
Denice S
DS
Feig
Onil
O
Bhattacharyya
Arlene S
AS
Bierman
D000328:Adult; D000368:Aged; D003920:Diabetes Mellitus / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality; D012189:Retrospective Studies; D012923:Social Class; D012959:Socioeconomic Factors; D020521:Stroke / Q000401:mortality; D019472:Universal Health Insurance / Q000706:statistics & numerical data*; D055815:Young Adult