Diabetes an independent risk factor for heart failure: Mayo Clinic Study
Rochester, MN: Diabetes mellitus (DM) alone is an independent risk factor for the development of heart failure (HF), according to a recent study in the journal Mayo Clinic Proceedings.
According to the study, diabetes patients had an increased incidence of heart failure even in the absence of underlying diastolic dysfunction-- Approximately 21% (22 of 116) of patients with diabetes developed HF over 10 years compared with patients without diabetes (12% [24 of 232]). The findings support the concept of DM cardiomyopathy -- defined by the existence of abnormal myocardial structure and performance in the absence of other cardiac risk factors, such as coronary artery disease, hypertension, and significant valvular disease, in individuals with diabetes mellitus.
Diabetes is a major health problem in India and worldwide and is one of the leading causes of death in India, despite improvements in medical therapy. Cardiovascular complications in patients with DM are especially debilitating and account for a large portion of morbidity and mortality in DM.
Cardiovascular complications of DM patients include coronary artery disease, stroke, atherosclerosis, and hypertension (HTN). Also, diabetes patients are at an increased risk for the development of HF. Due to the concurrent presence of HTN and coronary heart disease in many patients with DM, the incidence of HF and DCM due to DM is not well defined.
Horng Chen, a cardiologist at Mayo Clinic in Rochester, Minnesota, and colleagues conducted the study to delineate the impact of diabetes mellitus on the development of cardiovascular diseases in a community population.
Utilizing the Rochester Epidemiology Project, researchers evaluated the long-term impact of diabetes on the development of heart failure, both with preserved ejection fraction — a measurement of the percentage of blood leaving the heart with each contraction — and reduced ejection fraction. They also looked at mortality in a community population, controlling for hypertension, coronary artery disease, and diastolic function.
From an initial group of 2,042 residents of Olmsted County, 116 study participants with diabetes were matched 1:2 for age, hypertension, sex, coronary artery disease and diastolic dysfunction to 232 participants without diabetes.
Key findings of the study include:
- Over the 10-year follow-up period, 21% of participants with diabetes developed heart failure, independent of other causes.
- In comparison, only 12% of patients without diabetes developed heart failure.
- Cardiac death, heart attack, and stroke were not statistically different in the study between the two groups.
- Those with DM had a higher body mass index and plasma insulin and serum glucose levels.
- Although left ventricular ejection fractions were similar, E/e' ratio (9.7 vs 8.5) was higher in DM vs non-DM.
- During a follow-up of 10.8 years, participants with DM had a higher incidence of heart failure (HF); hazard ratio, 2.1 and 10-year Kaplan-Meier rate of 21% (22 of 116) vs 12% (24 of 232) compared with those without DM.
- In the subgroup of participants without diastolic dysfunction those with DM had an increased risk for HF; hazard ratio, 2.5.
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The study shows that diabetes is an independent risk factor for the development of heart failure in the community-dwelling population. Furthermore, the outcome data support the concept of diabetic cardiomyopathy.
This research extends previous findings and demonstrates that even without a known cardiac structural abnormality and with a normal ejection fraction, diabetic patients are still at increased risk of developing heart failure as compared to their nondiabetic counterparts.
"Our hope is that this study provides a strong foundation for further investigations into diabetes and heart failure. There is still much to learn and study in terms of this association and how to best diagnose and treat this condition," says Dr. Chen.
The study, "Diabetes Mellitus Is an Independent Predictor for the Development of Heart Failure," is published in the journal Mayo Clinic Proceedings.