# Impact of Winter Season on Inpatient Outcomes and Trends in Cardiac Arrest Hospitalizations: A Nationwide Analysis

## TL;DR

This study shows that cardiac arrest patients hospitalized in winter have higher mortality and fewer advanced treatments, despite lower hospital costs.

## Contribution

The study provides a nationwide analysis of seasonal impacts on cardiac arrest inpatient outcomes and hospitalization trends.

## Key findings

- Winter hospitalizations for cardiac arrest had higher mortality (63.3% vs. 60.9%) compared to non-winter months.
- Winter hospitalizations were associated with fewer advanced interventions and lower hospital costs.
- The rate of cardiac arrest hospitalizations increased from 2016 to 2020 in both winter and non-winter months.

## Abstract

Background: Cardiac arrest presents a critical medical emergency with substantial morbidity and mortality. Seasonal variations, particularly during winter, have been associated with increased cardiovascular risks. However, the impact of winter on inpatient outcomes following cardiac arrest remains underexplored. This nationwide analysis aims to quantify the influence of the winter season on inpatient outcomes and trends in cardiac arrest hospitalizations.

Methods: Data spanning 2016-2020 were extracted from the National Inpatient Sample (NIS) Database Registry. Patients with cardiac arrest were categorized based on hospitalization during winter (November to January) and non-winter (February to October) months. Inclusion criteria, study variables, and outcomes, such as mortality, respiratory failure, interventions, and hospital costs, were assessed. Statistical analyses, including logistic and linear regression models, were employed to determine unadjusted and adjusted outcomes.

Results: Of 1,048,955 cardiac arrest patients, 286,210 were hospitalized during winter. Winter hospitalizations exhibited higher mortality (63.3% vs. 60.9%), even after adjustments (adjusted odds ratio: 1.08; 95% confidence interval 1.05 - 1.11, p<0.001). Reduced odds of advanced interventions (mechanical circulatory support, percutaneous coronary intervention, pacemaker placement) were observed in winter hospitalizations. Unexpectedly, lower hospital costs were associated with winter hospitalizations ($171,115 vs. $177,536, p=0.012). Clinical outcomes (respiratory failure, in-hospital resuscitation, targeted temperature management, hospital length of stay) were comparable between winter and non-winter cohorts. Temporal trends showed an increasing rate of cardiac arrest in both cohorts from 2016 to 2020.

Conclusion: This nationwide analysis reveals the critical impact of winter on inpatient outcomes following cardiac arrest. The findings underscore the urgency of tailored interventions during winter, potential disparities in advanced cardiovascular care, and the need for ongoing research to elucidate economic considerations and optimize patient care strategies.