Influence of diabetes and diabetes-gender interaction on the risk of death in patients hospitalized with congestive heart failure.

OBJECTIVES: The purpose of this study was to investigate the influence of diabetes on long-term mortality in a large cohort of patients hospitalized with heart failure (HF).
BACKGROUND: Diabetes is common in HF patients, but information on the prognostic effect of diabetes is sparse.
METHODS: The study is an analysis of survival data comprising 5,491 patients consecutively hospitalized with new or worsening HF and screened for entry into the Danish Investigations of Arrhythmia and Mortality on Dofetilide (DIAMOND). Screening, which included obtaining an echocardiogram in 95% of the patients, took place at Danish hospitals between 1993 and 1995. The follow-up time was five to eight years.
RESULTS: A history of diabetes was found in 900 patients (16%), 41% of whom were female. Among the diabetic patients, 755 (84%) died during follow-up, compared with 3,200 (70%) among the non-diabetic patients, resulting in a risk ratio (RR) of death in diabetic patients of 1.5 (95% confidence interval [CI] 1.4 to 1.6, p < 0.0001). In a multivariate analysis, the RR of death in diabetic patients was 1.5 (CI 1.3 to 1.76, p < 0.0001), but a significant interaction between diabetes and gender was found. Diabetes increased the mortality risk more in women than in men, with the RR for diabetic men being 1.4 (95% CI 1.3 to 1.6, p < 0.0001) and 1.7 for diabetic women (95% CI 1.4 to 1.9, p < 0.0001). The effect of diabetes on mortality was similar in patients with depressed and normal left ventricular systolic function.
CONCLUSIONS: Diabetes is a potent, independent risk factor for mortality in patients hospitalized with HF. The excess risk in diabetic patients appears to be particularly prominent in females.