Similar incidence of ICD-shocks in diabetic compared to non-diabetic patients receiving implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D)
Authors: Haxha S , Zareini B , Halili A , Ruwald M H , Koeber L , Philbert B T , Gislason G , Pedersen-Bjergaard U , Torp-Pedersen C , Bang C 
Published: October 2024

Abstract

Background and aims
Recent studies have suggested that diabetes patients with implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) may experience a reduced incidence of appropriate ICD-shocks and an increased mortality rate. This study aims to assess whether there is parity in ATP-treatment and ICD-shocks between patients with and without type 2 diabetes mellitus (T2DM), and to analyze associated mortality rates.

Methods
Using the Danish pacemaker and ICD registry we included patients who received a first-time ICD or CRT-D implantation with a primary or secondary prophylactic indication, between January 1st 2000 to December 31st 2018. Outcomes were analyzed individually for each outcome. Cause specific Cox was used for i) appropriate ATP therapy or ICD-shock, ii) inappropriate ATP therapy or ICD-shock, and a standard Cox regression model was used for iii) all-cause mortality, iv) mortality rate following an ATP-therapy or ICD-shock. Cumulative incidence curves, generated using the Aalen Johansen estimator, were utilized to compare the incidence rates for ATP therapy and ICD-shock while accounting for competing risk of death, while Kaplan-Meier methodology was utilized for survival curves. Analyses were conducted in the total population and in subgroups divided on indication and device type.

Results
Out of 14 747 patients who received an ICD or CRT-D, 4377 (30%) had T2DM, 4593 (31%) patients received first-time appropriate ATP therapy or ICD-shock, and 1244 (8,4%) experienced first-time inappropriate treatments, 5 112 (35%) experienced death during the follow-up time (mean 3.9 years (SD 2.7)). T2DM patients were more likely to be male (85% vs 80%), slightly older (66 vs 65 years) and burdened with more comorbidities. No significant differences were seen between T2DM and non-T2DM patients for appropriate ATP therapy (HR 0.96[0.88:1.04] p=0.31), appropriate ICD-shock (HR 0.95[0.86:1.05] p=0.32), inappropriate ATP therapy (HR 0.92 [0.77;1.09] p=0.32) and inappropriate ICD-shock (HR 0.96 [0.78;1.18] p=0.71). In the subgroup analyses, no difference was seen in the primary prophylactic subgroups (Figure 1.), only significant difference was observed in the secondary prophylactic ICD group who received less ATP-therapy at 5-year follow-up (HR0.83[0.70;0.99] p=0.04), and in the secondary prophylactic CRT-D group, were T2DM patients seemed to experience more appropriate ICD-shock treatments (HR 2.07[1.23;3.48] p=0.006). Further, we found a higher mortality rate in T2DM with primary prophylactic ICD (HR 1.46[1.31;1.62] p&lt;0.001) and secondary prophylactic ICD (HR 1.30[1.13;1.51] p&lt;0.001), (Figure 2.) this mortality rate remained largely unchanged post appropriate ATP or ICD-shock in the ICD subgroups.

Conclusions
Despite similar incidence of ATP-therapy and ICD-shocks, T2DM patients with ICD-device experienced a significantly higher post-treatment mortality and all-cause mortality rate.