Association between type-2 diabetes mellitus and post-discharge outcomes in heart failure patients: Findings from the RICA registry

Abstract

Aims

Heart failure (HF) and diabetes are common clinical conditions that may coexist. The main objective was to analyze the association of type-2 diabetes mellitus (T2DM) on prognosis in hospitalized patients with HF.

Methods

We evaluated the association between T2DM with all-cause mortality and readmissions in the Spanish National Registry on Heart Failure—“Registro Nacional de Insuficiencia Cardiaca” (RICA). This is a multi-center and prospective cohort study that includes patients admitted for decompensated HF from 2008 to 2011. Study endpoints were all-cause mortality and hospital readmission. We determined the adjusted hazard ratio (HR) by a multivariable Cox regression model.

Results

A total of 1082 patients (mean age 77.6 ± 8.5) were included of whom 490 (45.3%) had diabetes and 592 patients (54.7%) had preserved left ventricular ejection fraction (LVEF). During one-year follow-up, 287 patients died (151 patients with diabetes) and 383 patients were readmitted (197 patients with diabetes). After adjusting for baseline characteristics T2DM was significantly associated with all-cause mortality (HR 1.54; 95%CI 1.20–1.97, p = 0.001) and readmissions (HR 1.46; 95%CI 1.18–1.80, p < 0.001). Age, dementia, peripheral vascular disease, NYHA class, renal insufficiency, hyponatremia and anemia were also independently associated with outcomes. There were no differences in mortality (p = 0.415) and readmissions (p = 0.514) according to preserved or reduced LVEF.

Conclusion

T2DM is very common in patients hospitalized for HF. This condition is a strong and independent co-morbidity of all-cause mortality and readmission for both HF with preserved and reduced LVEF.

Introduction

Heart failure (HF) and diabetes are both common clinical entities that frequently coexist. The estimated prevalence of diabetes in HF patients has been reported between 40 and 50% [1], [2], [3]. Despite the high frequency of diabetes in HF patients, data describing the clinical profile and prognosis of this subgroup are still scarce. The coexistence of diabetes and HF increases the mortality rate compared with patients without diabetes. This related excess mortality applies to HF with both reduced and preserved left ventricular ejection fraction (LVEF) and to HF of both ischemic and non-ischemic etiology [4], [5], [6], [7].

The increased morbidity and mortality, associated to diabetes, may be related to other comorbidities observed in this population, such as renal dysfunction and anemia, which could be intimately related to diabetes [8]. Most of the information on clinical profile and prognostic come from clinical trials and registry from chronic patients with depressed left ventricular ejection fraction (LVEF) [2]. There is current limited information derived from real world where patients with preserved LVEF are even more frequent.

The influence of diabetes as an independent predictor of long-term outcomes after hospitalization for HF has been previously studied. The ALARM-HF observational survey evaluated in-hospital mortality among HF patients according to diabetes status with only 15% of patients with preserved LVEF [9]. There was a similar risk of in-hospital mortality in patients with and without diabetes in the landmark ADHERE database, but there is not post-discharge data in this registry [10]. Results from the OPTIMIZE-HF registry also did not find differences between in-hospital and post-discharge mortality according to diabetes condition at 90-day follow-up either [11]. The DIAMOND study showed an increased mortality in patients with diabetes, this excess risk was particularly prominent in females [5]. The EVEREST study, including patients with depressed LVEF, showed that patients with diabetes had a higher post-discharge outcomes compared with patients without diabetes. EVEREST did not distinguish between both types of diabetes and it also did not include patients with preserved LVEF.

We aimed to investigate the clinical characteristics and long-term impact of T2DM among hospitalized patients with HF in real-world conditions.