With the U.S. Department of Health and Human Services reporting rising ICU utilization across the country due to COVID-19, the light at the end of the pandemic tunnel many had hoped to see appears to have dimmed considerably. The HHS data shows that in states like Florida, Louisiana and Mississippi, nearly half of occupied adult ICU beds are taken by COVID-19 patients. A recent study in JAMA Network, however, reveals some possibly surprising news: COVID-19 was one of the leading causes of death for Americans in 2020, but not the leading one. The study, authored by Farida B. Ahmad, MPH, and Robert N. Anderson, Ph.D, used data from the National Vital Statistics System at the National Center for Health Statistics in Hyattsville, Md. "The NVSS collects, processes, tabulates, and disseminates vital statistics based on death certificates filed in the 50 states and the District of Columbia," the study's authors state. "Cause-of-death data are based on the underlying cause of death, which is the disease or condition responsible for initiating the chain of events leading to death." The study takes a look at the leading causes of death in the U.S. from the years 2015 to 2020. COVID-19 was the third leading cause of death in the country last year and was responsible for the significant rise in deaths from 2019 (2,854,838) to 2020 (3,358,814). In 2018, total deaths in the U.S. numbered 2,839,205. The leading cause of death in 2020 was heart disease, followed by cancer, as has been the trend since 2015, according to the study. Heart disease deaths have increased since 2019, while deaths from cancer dropped slightly over the same period. The study notes there were increases in other causes of death, such as diabetes, Alzheimer's disease, and unintentional injury. "Alzheimer's disease, and diabetes, may also reflect disruptions in health care that hampered early detection and disease management," the authors say. "Increases in unintentional injury deaths in 2020 were largely driven by drug overdose deaths." See our slideshow above for the leading causes of death from 2015 to 2020, and click here to read the full study.