Long-Term Clinical Outcomes of Implantable Cardioverter Defibrillator Recipients in New Zealand: A Subanalysis by Sex, Age Group, and Ethnicity

Abstract

The long-term clinical outcomes of implantable cardioverter defibrillator (ICD) recipients across New Zealand are unknown. This study provides a detailed subanalysis of long-term clinical outcomes of ICD recipients by sex, age group, and ethnicity. All patients with an ICD implant between 2010 and 2019 were identified using the National Minimum Dataset, which collects all public hospital admissions in New Zealand using International Statistical Classification of Diseases and Related Health Problems, Tenth Revision, Australian Modification (ICD10-AM) procedure coding. There were 4,261 patients with a mean follow-up of 4.85±2.76 years. The median age was 62 years and 78.9% were male. The all-cause mortality was higher in males compared with females (23.1% vs 17.2%; p<0.001). There was no significant difference by primary and secondary prevention indication ICD in each sex group. Heart failure (HF) hospitalisation was higher in males compared with females (29.4% vs 26.6%; p=0.009). All-cause mortality was highest in the age group of ≥80 years and lowest in those <40 years (44.1% vs 8.4%, p<0.001). HF hospitalisation was highest in the age group of 70–79 years and lowest in the age group <40 years (36.5% vs 16.1%; p<0.001). All-cause mortality was highest in Māori and lowest in Asians (26.7% vs 15.9%; p<0.001). Heart failure hospitalisation was highest in Māori and lowest in Europeans (36.1% vs 26.3%; p<0.001). In New Zealand, all-cause mortality and HF hospitalisation was highest in males and Māori ICD recipients. These disparities in clinical outcomes warrant further investigation.