BACKGROUND:

Despite regular health care, preventive health issues may be neglected in patients with chronic diseases such as diabetes. Case-control studies in the United States have shown lower mammogram rates in women with diabetes; however, it is not known whether the presence of diabetes mellitus affects mammography use in a Canadian setting, where there is universal access to health care.

METHODS:

Using health databases in Ontario from April 1, 1999, to March 31, 2002, this retrospective cohort study observed women aged 50 to 67 years, who were free of breast cancer, until their first mammogram in a 2-year period. Mammogram rates were compared between women who had had diabetes for a minimum of 2 years (n = 69 168) and women without diabetes (n = 663 519).

RESULTS:

Compared with women without diabetes, diabetic patients were older, had more physician visits, were more often from a lower-income neighborhood, and, in those 65 years or older, were less likely to be taking estrogen. The odds ratio of having a mammogram during the 2-year period was 0.68 (95% confidence interval, 0.67-0.70; P<.001) for women with diabetes, and adjustment for age and other covariates did not modify this effect.

CONCLUSIONS:

Women with diabetes were significantly less likely to have had a mammogram during a 2-year period than were women without diabetes, despite more health care visits. These results suggest that, because of the complexity involved in diabetes care, routine preventive care such as cancer screening is often neglected. These findings highlight the need for better organization of primary care for patients with chronic diseases.