Postmenopausal women with heart disease have three times the risk of developing heart failure if they also have diabetes, researchers report in the Sept. 7 Circulation. In addition, diabetic women in the study who also had kidney disease or obesity, or whose diabetes was poorly controlled (fasting blood sugar levels above 300 mg/dL) had a risk of heart failure six to 10 times higher than that of women without diabetes.
Researchers analyzed records from 2,391 participants in the Heart and Estrogen/Progesterone Replacement Study (HERS) to determine risk factors for developing heart failure. Previous studies recognized some significant differences in heart failure between men and women. In men, for example, a heart attack more often precedes heart failure. “In women, heart failure seems to happen often in the absence of a heart attack,” said Kirsten Bibbins-Domingo, MD, PhD, the lead author and an instructor in medicine, epidemiology, and biostatistics at the University of California, San Francisco.
Heart failure is a condition in which the heart can't pump enough blood to the body's other organs. Physicians diagnose about 550,000 new cases of congestive heart failure annually, and the condition kills nearly 53,000 Americans each year.
In the study, 237 of the women (average age 68.3) developed heart failure during an average of 6.3 years in HERS and its follow-up. The HERS trial tested the effectiveness of hormones in preventing a second heart attack in women who had already suffered one. The study revealed nine health factors that identify postmenopausal women with coronary artery disease who have an increased risk of developing congestive heart failure. Diabetes was the most powerful predictor of heart failure. Women who had the disease on entering HERS were 3.1 times more likely to develop heart failure than women who did not. The risk from atrial fibrillation was nearly as great. Women with this abnormal heart rhythm were 2.9 times more likely to develop heart failure than women who did not have the condition.
The seven other factors are, in descending order of significance: two or more previous heart attacks, insufficient kidney function, hypertension, obesity, current smoking, and two heart disorders, left bundle branch block (a block in electrical impulses through the heart) and left ventricular hypertrophy.
Among other findings were that diabetic women with well-controlled blood sugar levels had a relatively low rate of heart failure, and the danger of developing heart failure increased in women with multiple risk factors. For example, women with none of the nine risk factors had an annual incidence of only 0.4 percent, while women with three or more risk factors but no diabetes had a 3.4 percent annual incidence of heart failure. The yearly incidence for diabetic women who had three additional risk factors rose to 8.2 percent. For women who had diabetes and kidney disease, the annual incidence of heart failure was 13 percent, and estrogen/progestin use was not associated with developing heart failure. They also found that a heart attack increased a woman's risk of heart failure to 1.4 times that of women who had not had one. Women with two or more heart attacks had a risk 2.5 times greater, and that women with systolic blood pressure readings greater than 140 mmHg had a 2.1 times greater risk than those whose systolic pressure ranged from 80 to 120 mmHg. Current smokers had 1.9 times the risk of heart failure, and women with a body mass index of more than 35 kg/m2 had a 1.9 times greater risk than those with a BMI of less than 25 kg/m2.