Poor glucose control hikes stroke risk in diabetic women

Women with type 2 diabetes and poorly controlled blood glucose, but not men, may be at elevated risk for stroke, results from a prospective study suggest.

Among women, every 1% increase in HbA1c from baseline was associated with a relative 5% increase in the risk for stroke during follow-up (hazard ratio 1.05, 95% CI: 1.02-1.07), Gang Hu, MD, PhD, of Pennington Biomedical Research Center in Baton Rouge, La., and colleagues reported in Diabetologia. The association was not significant in men.

The association was consistent among both black and white patients and both those who were and were not taking glucose-lowering medications. Stroke risk was also greater for women aged 55 years and older, the researchers found.

“This is important to keep in mind when studying blood sugar level and other cardiovascular disease risk factors in the diabetic population and when planning a strategy to prevent cardiovascular disease, especially for women with type 2 diabetes,” they wrote.

Hu and colleagues analyzed data from 10,876 men and 19,278 women with newly diagnosed type 2 diabetes who participated in the Louisiana State University Hospital-Based Longitudinal Study.

At baseline, participants had not had a stroke, were free of coronary heart disease and glycemic control was worse among men than women (HbA1c 8.1% vs. 7.6%). More than half of patients were black (56% of men and 59% of women).

Overall, 2,949 strokes occurred during the mean 6.7 year follow-up period. Although men had a higher rate of stroke, poor glycemic control correlated with stroke risk in women only.

Compared with a women whose HbA1c was 6% to 6.9% at baseline, those with levels 8% or higher had significantly increased risk during follow-up. Hazard ratios by HbA1c values were as follows:

• 8% to 8.9%, HR 1.19 (95% CI: 1.00-1.42)
• 9% to 9.9%, HR 1.32 (95% CI: 1.09-1.59)
• 10% or higher, HR 1.42 (95% CI: 1.23-1.65)

The association remained significant among women with type 2 diabetes even after the researchers adjusted for systolic BP, LDL cholesterol and treatment with medication.

The study population was disproportionately low socioeconomic status patients, and the findings may not be applicable to populations with a greater proportion of middle-to-high socioeconomic status patients, the researchers acknowledged. Other limitations included basing stroke diagnoses on hospital discharge data without confirmation. Residual confounding could not be ruled out.