Does renal function influence the prognostic impact of type 2 diabetes mellitus in patients with chronic heart failure and left ventricular dysfunction?

Hypothesis: Type 2 diabetes mellitus (T2DM) and chronic heart failure (CHF) are associated with renal dysfunction. We tested the hypothesis that the degree of renal dysfunction influences the negative impact on the outcome of T2DM in patients with CHF and reduced left ventricular ejection fraction (LVEF). Methods: From November 1, 2009 to December 31, 2012, the “Trieste Registry of CV Diseases” enrolled 19,589 patients. Those with diagnosis of CHF and reduced LVEF were analyzed. The primary end-point was all-cause mortality. Results: 554 patients were selected (73 ± 10 years old, 32% females), 192 had T2DM (35%). During followup (23±11 months), all-cause death occurred in 57 patients (30%) who had T2DM and in 58 (16%, p b 0.001)who had not; T2DM was associated with an increased risk of death (adjusted HR 2.55 [95% CI 1.02-6.36], p= 0.04). The prognostic impact of T2DM was lost when patients were selected according to renal function: adjusted HR 1.44 [0.21-9.93], p= 0.71, in patients with normal renal function, defined as estimated glomerular filtration rate (eGFR) N60, and adjusted HR 3.37 [0.96-11.80], p = 0.08 in patients with renal dysfunction (eGFR b 60 ml/min ∗ 1.73 m2). T2DM predicted all-cause mortality only in the subgroup with eGFR between 90 and 30 ml/min ∗ 1.73 m2 (adjusted HR 2.52 [1.01-6.30], p= 0.04). Conclusions: In patients with CHF and reduced LVEF the prognostic impact of T2DM depends on the degree of renal dysfunction. Its contribution in all-causemortality risk prediction is limited tomild–moderate renal dysfunction subgroup, while prognostic power is lost in normal renal function and in severe renal dysfunction patients.