Sudden Death in Young Adults Coming to Emergency Department: A Retrospective Study of Epidemiological Trends in the Pre- and Post-COVID Eras

Background Sudden death in young adults is a major public health concern with diverse etiologies. While cardiac causes are often emphasized, the role of non-cardiac causes and the impact of the COVID-19 pandemic remain underexplored, particularly in South Asia. This study aimed to assess the epidemiological patterns, etiological distribution, and demographic characteristics of sudden deaths in young adults, and to evaluate shifts following the onset of the COVID-19 pandemic in Karachi, Pakistan. Methods A retrospective analysis was conducted among patients aged 18–40 years who experienced sudden death, defined as death within 24 hours of symptom onset, at the emergency departments of Aga Khan University Hospital (AKUH) and Indus Hospital and Health Network (IHHN) between January 2018 and September 2023. Exclusion criteria included trauma, suicide, drowning, overdose, and end-stage metastatic cancer. Data were extracted from electronic health records and analyzed using descriptive statistics, chi-square, and t-tests. Results A total of 855 cases were included, with 280 (33%) in the pre-COVID era and 575 (67%) in the post-COVID era. The mean age was 29.5 ± 6.4 years, with 56% male and 54% aged 18–30 years. Non-cardiac causes predominated (86%), with diabetic ketoacidosis (21.1%), seizures (12.5%), and respiratory failure (13.5%) being most common. Cardiac causes (5.4%) were mainly structural heart diseases, while 8.3% of cases were unexplained. Oxygen saturation at triage was significantly lower post-COVID (83.3% vs. 86.4%, p = 0.016). Among AKUH post-COVID cases with available vaccination data, 28% were unvaccinated, 12.2% partially vaccinated, and 2.8% fully vaccinated. Conclusion Non-cardiac causes, particularly metabolic and neurological emergencies, were the leading contributors to sudden death among young adults in Karachi. The increase in cases during the COVID-19 era highlights both direct and indirect effects of the pandemic. These findings emphasize the need for improved pre-hospital emergency response, early recognition of high-risk conditions, and preventive strategies to reduce avoidable mortality in young populations.