FRIDAY, Sept. 11, 2020 (HealthDay News) -- There may have been cases of COVID-19 in Los Angeles as early as last December, months before the first known U.S. cases were identified, a new study claims.
Researchers analyzed data from more than 10 million patient visit records for University of California, Los Angeles (UCLA) Health outpatient, emergency department and hospital facilities. They compared data from the period between Dec. 1, 2019, and Feb. 29, 2020, to data from the same months in the previous five years.
Outpatient visits for coughs increased 50% in the months before the pandemic, and exceeded the average number of visits for the same symptoms by more than 1,000 compared with the same time period in the previous five years.
The researchers also found that in the months before the pandemic, there was a significant increase in the number of patients with coughs seen at emergency departments, and in the number of patients hospitalized with acute respiratory failure.
The study was published Sept. 10 in the Journal of Medical Internet Research.
Other factors -- such as the flu and vaping -- could have contributed to some of the unexpected increase, but the findings show the importance of analyzing electronic health records to quickly identify unusual changes in patient patterns, according to the researchers.
"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 study lead author Dr. Joann Elmore, a professor of medicine at UCLA's David Geffen School of Medicine.
"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," she said in an UCLA news release.
"We may never truly know if these excess patients represented early and undetected COVID-19 cases in our area," Elmore said. "But the lessons learned from this pandemic, paired with health care analytics that enable real-time surveillance of disease and symptoms, can potentially help us identify and track emerging outbreaks and future epidemics."
The U.S. Centers for Disease Control and Prevention has more on COVID-19.