P1167Effect of diabetes on all-cause mortality in CRT patients
Authors: Merkel E D , Behon A , Schwertner W R , Pinter A , Osztheimer I , Geller L , Zima E , Becker D P , Kosztin A , Merkely B 
Published: June 2020

Abstract

Background
Heart failure patients with diabetes mellitus (DM) have a higher risk for all-cause mortality and also for sudden cardiac death. We lack data on the effect of adding an implantable cardioverter defibrillator (ICD) to cardiac resynchronization therapy (CRT) on all-cause mortality in diabetic heart failure patients.

Purpose
We aimed to investigate the risk of DM on all-cause mortality in CRT patients, and to examine the beneficial effect of adding an ICD on all-cause mortality by left ventricular ejection fraction in CRT patients with or without DM.

Methods
We examined retrospectively 2525 patients who underwent CRT implantation based on the current guidelines at our clinic between June 2000 and September 2018, of which 928 (36%) had diabetes. The primary endpoint was all-cause mortality, also expressed as events per 100 person-year by quintiles of ejection fraction (EF) with or without an ICD or DM. Time to event data was investigated by Kaplan Meier and multivariate Cox regressional analysis.

Results
During our mean follow-up time of 4.6 years, 1432 (56%) patients reached the primary endpoint, of which 553 (38%) had DM. In the DM group, hypertension (82% vs. 66%; p‹0.01), ischemic etiology (56% vs. 44%; p‹0.01), myocardial infarction (43% vs. 36%; p‹0.01) was more frequent compared to non-DM group. There was no difference between the two groups regarding the implantation of an ICD (54% vs. 53%; p = 0,84). Those with DM showed a 25% higher risk of all-cause mortality (HR 1.25; 95% CI 1.12-1.40; p‹0.01), also observable after adjusting for relevant clinical covariates such as age, gender, atrial fibrillation and the addition of an ICD (HR 1.17; 95% CI 1.06-1.31; p‹0.01). Examined as all-cause mortality per 100 person-year follow up, patients with EF›30% and DM (13,7 events/ 100 person-year follow-up for an EF 30-35%) showed similar risk as those without DM and a severely impaired left ventricular function with EF‹25% (14 events/100 person-year follow-up for an EF &lt;25%). Investigating the composite end-point of all-cause mortality and heart failure hospitalization, those with DM showed a 21% higher risk than non-DM CRT patients (HR 1.21; CI 1.09-1.34; p = 0 &lt; 0.001). Adding an ICD for CRT patients with DM reduces the risk of all-cause mortality significantly by 32% (HR 0,68; CI 0,56 to 0,82; p &lt; 0.001) during the first six years but diminished on longer follow-up time.

Conclusions
Diabetes was found as an independent predictor of all-cause mortality in CRT patients. Those with a left ventricular ejection fraction above 30% have comparable risk of mortality as non-diabetic patients with a severely impaired left ventricular function. In diabetic CRT patients the addition of an ICD reduces the risk of all-cause mortality mostly seen in the first six years. These findings might implicate the relevance of adding an ICD to CRT even at a higher ejection fraction in those with severe comorbidities such as diabetes.
Abstract Figure. All-cause mortality in CRT, DM patients