UAB Study Reveals Sex- and Age-Related Differences

Diabetes is a documented risk factor for cardiovascular disease, including heart failure (HF), and the prognosis of patients with HF is worse in the presence of diabetes. Some research suggests diabetes-associated increased mortality in HF may be worse in women than in men.

A new study published in Heart confirms the additive consequences of diabetes in women with HF (Heart. 2007; 93:1584-1590). The findings from that study also suggest diabetes-associated increased mortality and hospitalization in HF is primarily observed in older women. This is important as most HF patients are older adults, and HF is the number one reason for hospital admission in this population.

Ali Ahmed, MD, MPH, director of UAB’s Geriatric Heart Failure Clinic and Research Program, led the multicenter research team investigating diabetes’ effect on the natural history of HF. Ahmed designed a propensity-matched study of HF patients participating in the National Heart, Lung, and Blood Institute-funded Digitalis Investigation Group trial.

To reduce possible confounding effects of baseline variables, Ahmed and colleagues used propensity scores to match patients. Propensity matching created a cohort of patients (with and without diabetes) who were well balanced in all measured baseline covariates. No previous studies evaluating diabetes’ effect on HF outcomes have applied this technique.

Evaluation of more than 4000 matched HF patients demonstrated a complex, interactive relationship among sex, diabetes, and age. “The extent to which poorer outcomes are due directly to diabetes or are due to diabetes-associated comorbidities has not been well understood,” he says.

Examination of the effects of diabetes on mortality and hospitalization rates in HF patients revealed clear differences between men and women. HF patients of both sexes with diabetes have higher absolute risk values for mortality and hospitalization. Yet in women the effects of diabetes on mortality and hospitalization were significantly worse than in men. In men, for example, diabetes was associated with a 5% absolute increase in mortality; in women diabetes was linked to a 14% increase.

When investigators examined age-related effects of diabetes on mortality and hospitalization in groups of patients <65 years and >65 years, older women suffered the most consequences. Diabetes was associated with a 19% absolute increase in mortality among older women compared with a 4% increase in older men. In younger men the absolute increase in mortality was 6%, versus 8% in younger women.

In the next 20 years the number of elderly women with HF is projected to double. “Because the prevalence of diabetes also increases with age, the numbers of older women with HF and diabetes will rise,” he says.

Ahmed advocates improving diabetes diagnosis and management in these patients. “Preventing diabetes in elderly women with heart failure and preventing heart failure in elderly women with diabetes are key components for optimizing outcomes for patients with both diseases,” he says.

For more information:
Dr. Ali Ahmed
1.800.UAB.MIST
mist@uabmc.edu