D2.123 - Temporal Stability of Asthma-Related Out-of-Hospital Cardiac Arrest: A Nationwide SARIMA Analysis of Korean Data From 2013 to 2023

Asthma is a common chronic respiratory disease and a potential contributor to out-of-hospital cardiac arrest (OHCA). However, whether asthma-related OHCA represents a dynamically changing public health burden or a temporally stable phenomenon remains unclear. Understanding long-term temporal patterns is essential for interpreting outcome analyses and planning targeted preventive strategies.

Using the Korean nationwide OHCA registry, we analyzed all adult OHCA cases recorded between 2013 and 2023. Asthma history was identified using a standardized respiratory comorbidity variable. Monthly proportions of asthma-related OHCA were constructed for the overall cohort and for patients aged ≥70 years. Time-series characteristics were evaluated using seasonal autoregressive integrated moving average (SARIMA) models. Model adequacy was assessed using Akaike information criteria (AIC), residual diagnostics, and Ljung–Box tests. Descriptive analyses stratified trends by age group and sex.

Across more than 450,000 OHCA cases, asthma history accounted for a small but consistent proportion of events. Over the 10-year period, no marked secular increase or decrease was observed. In both the overall cohort and the ≥70-year subgroup, the temporal pattern was best described by a non-seasonal ARIMA(1,0,0) model with a stable non-zero mean. Autoregressive coefficients indicated moderate temporal persistence, while residual diagnostics confirmed the absence of significant autocorrelation, supporting model adequacy (Table 1).

Age-stratified analyses demonstrated that asthma-related OHCA occurred predominantly in older individuals, with a higher concentration among elderly women. Despite demographic shifts in the general population, the relative contribution of asthma to OHCA remained temporally stable (Figure 1).

Asthma-related OHCA in Korea exhibits a stable and reproducible temporal structure over a decade, rather than a progressive or seasonal pattern. These findings suggest that asthma represents a persistent background vulnerability rather than an emerging driver of OHCA incidence. Establishing this temporal stability provides an essential framework for subsequent outcome analyses and supports the interpretation of asthma as a chronic, age-dependent risk context in OHCA rather than a time-varying exposure.