COVID-19 may have arrived in Los Angeles last year

The coronavirus may have already been spreading throughout Los Angeles by the end of last year. A major spike in acute respiratory failure at UCLA Health hospitals and clinics beginning in December suggests that COVID-19 was circulating in L.A. well before the first U.S. cases were identified. 

The researchers discovered that the number of patients admitted with symptoms including cough and respiratory failure from December 2019 to February 2020 was 50 percent higher than the number of such cases during the same time period over the five previous years.

According to the study authors, the findings demonstrate the importance of analyzing electronic health records to monitor and quickly identify irregular changes in patient populations. By focusing on data from both hospital and outpatient settings, as the team did for the current investigation, health care systems may be able to recognize epidemics sooner. 

Study lead author Dr. Joann Elmore is a professor in UCLA’s David Geffen School of Medicine.

“For many diseases, data from the outpatient setting can provide an early warning to emergency departments and hospital intensive care units of what is to come,” said Dr. Elmore. “The majority of COVID-19 studies evaluate hospitalization data, but we also looked at the larger outpatient clinic setting, where most patients turn first for medical care when illness and symptoms arise.”

The researchers noted that analyzing electronic patient records could help health care agencies more effectively identify and control outbreaks like the COVID-19 pandemic, which has killed hundreds of thousands of people worldwide.

“The pandemic has really highlighted our need for agile health care analytics that enable real-time symptom and disease surveillance using electronic health records data,” said study co-author Dr. Michael Pfeffer. “Technology, including artificial intelligence powered by machine learning, has further potential to identify and track irregular changes in health data, including significant excesses of patients with specific disease-type presentations in the weeks or months prior to an outbreak.”

The experts analyzed more than 10 million records from UCLA Health outpatient, emergency department, and hospital facilities. They compared data from December 1, 2019 to February 29, 2020 with data from the same period in each of the previous five years.

The study revealed that outpatient clinic visits by individuals seeking care for coughs increased by over 50 percent, exceeding the average number of visits for the same complaint by more than 1,000. There was a similar increase in the number of patients hospitalized with acute respiratory failure during this time period. 

The researchers acknowledge some study limitations. For example, other factors such as the flu could be responsible for some of the unexpected increase in patients treated for respiratory symptoms.

“We may never truly know if these excess patients represented early and undetected COVID-19 cases in our area,” said Dr. Elmore. “But the lessons learned from this pandemic, paired with healthcare analytics that enable real-time surveillance of disease and symptoms, can potentially help us identify and track emerging outbreaks and future epidemics.”

The study is published in the Journal of Medical Internet Research.

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By Chrissy Sexton, Earth.com Staff Writer