Several studies have reported the impact of diabetes on mortality and hospitalization in patients with heart failure (HF). However, the extent of this risk remains imperfectly known in community-based cohorts.

We examined the independent prognostic impact of diabetes on the one-year risk of mortality and hospitalization in patients with HF.

We conducted a prospective observational study NATURE-HF (National Tunisian Registry of Heart Failure) between October 2017 and January 2019. Demographics, clinical and etiological characteristics as well as one-year outcome were recorded.

Among 2040 patients with HF (mean age 63.6±12.6 years, 70.9% male), 731 (44.5%) had prior diabetes. Diabetic patients were older and had greater body mass index than non-diabetics. Left ejection fraction was similar in the two groups.

There was no significant difference in all-cause death (odds ratio [OR] [95% CI 1.29] [0.953, 1.615]) and cardiovascular death (0.956 [0.568, 1.609]) between diabetic and non-diabetic HF patients, however,diabetes was associated with a higher risk for hospitalization (2.208 [1.579, 3.089]), and the combined end point of all-cause death or hospitalization (1.654, [1.319, 2.072]). There was an increased risk for a composite of death or HF admissions in diabetic patients with ischemic cardiomyopathy (23.9 vs. 14.1% respectively, P<0.001).

The co-existence of heart failure and diabetes has significant impact on outcomes and confers a worse prognosis than heart failure alone, especially in patients with ischemic cardiomyopathy.