Background. The burden of comorbidities has gradually increased in patients with cardiac implantable electronic devices (CIEDs) during the past decades due to the overall aging population. 

Aim. We investigated 1) the influence of comorbidities on periprocedural complications of implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy pacemaker/ICD (CRT-P/-D) implantations or revisions and 2) determined the impact of comorbidities on outcomes.

Methods. Patients who underwent ICD or CRT-P/-D implantations or revisions were prospectively enrolled in the German Device Registry (50 participating nationwide centres) from March 2007 to February 2014. Patient characteristics, (peri-)procedural data, and complications were collected at the time of the device implantation or device revision. Primary outcomes were 1-year all-cause mortality and MACCE (mortality, stroke, myocardial infarction). Patients were categorized according to their comorbidities including prior stroke, chronic kidney disease (CKD), diabetes, and hypertension: group I: no comorbidities, group II: one comorbidity, group III: two comorbidities, group IV: 3 out of 4 comorbidities. Kaplan-Meier estimator for 1-year all-cause mortality was performed.

Results. Overall, 5449 patients were included (mean age 65.3 years) with 3794 ICD, 1535 CRT-D and 80 CRT-P implants/revisions with a median follow-up of 16 months. Of 5449 patients, 227 (4.2%) patients had a history of stroke, 889 (16.3%) CKD, 1050 (19.3%) diabetes, 1427 (26.2%) hypertension, and 1856 (34.1%) had none of these comorbidities. Periprocedural complications were not related to comorbidity burden (group I: 3.7% (56/1499), group II: 4.0% (62/1544), group III: 4.7% (42/889), group IV: 4.2% (10/238); p=0.69). Patients with a higher burden of comorbidities had a higher risk for MACCE (group I: 5.2% (93/1783), group II: 8.1% (160/965), group III: 10.3% (122/1187), group IV: 14.9% (50/445); p<0.001). Comorbidity burden was associated with a higher 1-year-all-cause mortality (p<0.001) (Figure 1). Patients with concomitant CKD showed the highest risk for 1-year-all cause mortality (13.5%, p<0.001) and MACCE (15.2% (132/867), p<0.001) compared to other comorbidities.

Conclusions. In the large-scale German Device Registry including patients with ICD and CRT-D/-P, a higher burden of comorbidities was not associated with increased periprocedural complications. As an increasing burden of comorbidities results in a higher 1-year all-cause mortality, competing comorbidities might decrease long-term benefits of CIED therapy. 

Figure 1: Kaplan-Meier curves for 1-year all-cause mortality depending on number of comorbidties (group I-IV: 0 CD, 1 CD, 2 CD 3/4 CD) such as prior stroke, chronic kidney disease, diabetes and hypertension.