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A research team led by Professor Hae Sun Suh of the College of Pharmacy delivered the world’s first cross-national, comprehensive analysis of COVID-19’s impact on disease-specific mortality, healthcare resource utilization, and disease burden

The COVID-19 pandemic rapidly reshaped population health and how people used healthcare worldwide. Yet most prior studies examined only a single disease or a single country, limiting what we could learn. To capture longer-term, system-wide effects, Professor Hae Sun Suh’s team analyzed ten years of large-scale medical big data from 31 countries across Europe, Asia, Oceania, and North America—including Australia, Taiwan, Japan, the United States, and the Republic of Korea. The findings were published in eClinicalMedicine (IF 10.0; top 3.2%) in July 2025 under the title, “Impact of COVID-19 on disease-specific mortality, healthcare resource utilization, and disease burden across a population over 1 billion in 31 countries: an interrupted time-series analysis.”

Pandemic ripple effects: higher mortality, worsened access to care
The research team comprised Professor Hae Sun Suh (lead), Dr. Kyungseon Choi and Student Minseol Jang of the Institute of Regulatory Innovation through Science; Professors Sang Jun Park (Seoul National University) and Siin Kim (Kyungsung University). Drawing on population-scale datasets covering more than one billion people, the team applied interrupted time-series (ITS) analysis to track changes in disease-specific mortality, healthcare resource utilization (HRU), and disease burden. To our knowledge, the scale and scope are unprecedented among COVID-19 studies to date.

According to the analysis, the pandemic period was marked by deterioration in access to care and statistically significant increases in disease-specific mortality and burden across multiple categories, including infectious, circulatory, digestive, and respiratory diseases. Within the circulatory group, mortality from ischemic heart disease continued on an upward trajectory beyond the initial shock of COVID-19, while deaths associated with hypertension and liver disease spiked sharply in the early phase.

In the immediate aftermath of the pandemic’s onset, HRU contracted across most conditions: outpatient visits fell, and hospital days shortened. Over time, oncology and mental-health services rebounded but a more granular look revealed divergence: chronic intestinal conditions saw continued declines in utilization, whereas outpatient encounters for thyroid and liver disorders, sleep disorders, and mood disorders increased—showing a split pattern across disease areas.

Professor Suh noted, “This study is the first to move beyond single-disease, single-country snapshots and show, at scale, how COVID-19 altered both mortality and access to care. The evidence points to a clear task for policymakers: protect continuity of care for vulnerable patients and build real-time data systems that keep health services running in the next crisis.” This research was supported by the Ministry of Food and Drug Safety’s Regulatory Science Program.