SAN FRANCISCO — Hyperglycemia and ethnicity each were independently associated with a greater risk for cardiovascular problems in a large, prospective study of 48,444 New Zealanders.
The information came from a New Zealand Ministry of Health program in which primary care physicians across the country were paid to collect and report data on patients with type 2 diabetes who had no history of cardiovascular disease and who were attending free annual visits for their diabetes. The investigators matched the glycemic data with national data on hospital admissions and death records to identify first cardiovascular events (ischemic heart disease, cerebrovascular accident, transient ischemic attack, or peripheral vascular disease), Dr. Paul L. Drury said at the annual scientific sessions of the American Diabetes Association.
During follow-up lasting a median of 2.4 years, 12% of the cohort had a first cardiovascular event. Each 1% increase in hemoglobin A1c (HbA1c) level was associated with a hazard ratio of 1.08, a statistically significant increase in risk, reported Dr. Drury, clinical director of diabetes services for the Auckland (New Zealand) District Health Board, and his associates. He has been an advisor to Eli Lilly & Co. and to Merck & Co., which make antidiabetes drugs.
The association between HbA1c and a first cardiovascular event was significant for both sexes. The results accounted for the effects of age at diagnosis, duration of diabetes, sex, ethnicity, socioeconomic status, smoking, systolic blood pressure, body mass index, the ratio of serum total cholesterol to HDL level, and the urine albumin-creatinine ratio.
Secondary analyses showed that Maori ethnicity was associated with a hazard ratio of 1.3 for developing a cardiovascular event, compared with non-Maori patients, after the researchers controlled for other factors. The study also confirmed the importance of classical risk factors for cardiovascular problems in patients with diabetes.