Impaired fasting glucose: a predictor of reduced survival in patients with heart failure

Abstract

Aims: Glucose abnormalities are associated with heart failure (HF), are increasingly prevalent, and may have an impact on outcome. Our aim was to evaluate the effect of fasting glucose levels on clinical outcome in patients with HF.

Methods and results: Patients with a diagnosis of HF as coded at a health maintenance organization in Jerusalem, Israel were evaluated retrospectively. Impaired fasting glucose (IFG) was defined as fasting plasma glucose levels between 100 and 125 mg/dL. All patients were followed for cardiac-related hospitalizations and death. A total of 6067 HF patients were included. Mean follow-up was 487 days; mean age 75 ± 13 years; 48% of the patients (n = 2,942) had diabetes; and 11.9% (n = 722) had IFG. Overall survival during the follow-up was 82.5%. Cox regression analysis after adjustment for significant predictors including age, gender, ischaemic heart disease, hyperlipidaemia, hypertension, body mass index, glomerular filtration rate, serum urea, sodium, and haemoglobin levels demonstrated that patients with diabetes and IFG had a very similar outcome. Both were significant predictors of reduced survival compared with 'normal' glucose levels (fasting glucose levels between 92 and 99 mg/dL) [diabetes, hazard ratio (HR) 1.42, 95% confidence interval (CI) 1.08-1.86, P = 0.01; IFG, HR 1.55, 95% CI 1.13-2.15, P < 0.01]. Diabetes and IFG were also predictors of increased cardiac-related hospitalizations (diabetes HR 1.31, 95% CI 1.16-1.48, P < 0.001; IFG, HR 1.17, 95% CI 1.00-1.35, P < 0.05).

Conclusions: Diabetes and IFG are common in patients with HF and have a similar effect on outcome including survival and cardiac hospitalizations. Glucose abnormalities including subclinical diabetes confer significant risk in patients with HF.

Keywords: Heart failure; Impaired fasting glucose; Outcome.