Age-stratified clinical phenotypes of cardiac implantable electronic device infections: a 20-year retrospective cohort study

Background The widespread adoption of cardiac implantable electronic devices (CIEDs) has been accompanied by a parallel increase in severe CIED infections. Traditional risk stratification frequently relies on binary age cutoffs, which can obscure how infection phenotypes evolve across a patient’s lifespan. This study evaluated how advancing age—analyzed across ordered chronological strata—correlates with anatomical infection site, device hardware type, microbiology, and in-hospital mortality in patients with CIED infections. Methods In this retrospective cohort study of 383 patients treated for CIED infections between 2002 and 2022, patients were categorized into five sequential age brackets (< 50 to 80–90 years). Age was modeled both categorically across these strata and continuously to estimate per-decade odds ratios (ORs) for clinical presentation, hardware type, and microbiological findings. Results The cohort was predominantly male (75.2%) with a mean age of 67.4 years. Pacemaker involvement increased significantly with age ( p < 0.001), whereas implantable cardioverter-defibrillator use declined ( p = 0.036). Localized generator pocket infections demonstrated a pronounced age-dependent gradient, rising from 19.4% in patients under 50 years to 73.0% in octogenarians ( p < 0.001; OR 1.43 per decade, 95% CI: 1.21–1.69). Conversely, systemic presentations—including bacteremia and lead endocarditis—showed no age-dependent trend. In-hospital mortality remained low and stable across age groups ( p = 0.452) but was markedly higher in patients presenting with bacteremia or sepsis compared to those without systemic involvement (16.7% vs. 1.6%, p < 0.001). Conclusions Analyzing age as a continuous spectrum reveals a distinct clinical phenotype dominated by localized pocket infections and low-power devices, an insight obscured by standard binary age cutoffs. Crucially, mortality risk was driven by systemic bloodstream infection rather than patient age itself, emphasizing that clinical surveillance should prioritize infection phenotype over chronological age alone. Clinical trial number Not applicable.