Explaining why wait times can be so lengthy in the emergency room, a new study by UC San Francisco reports that emergency department capacity hasn’t kept up with patient demand in California over the last decade.

The researchers found that the number of emergency departments (EDs) decreased by nearly 4% in California, while the number of ED visits rose by 7.4%. It is the first analysis of emergency medicine patterns in the state in recent years. The researchers also reported that the number of high-severity visits rose by nearly 68%, while the number of low-severity visits declined by 63%.

“We know that there is overcrowding in the ED,” said lead author Renee Y. Hsia, MD, a UCSF professor of emergency medicine. “Capacity has largely failed to match the rise in patient demand.”

The paper published June 22, 2023 in JAMA Network Open.

Amid numerous changes in the U.S. health care system in recent years, emergency departments (EDs) continue to play a vital role in the system. EDs are required to treat all patients regardless of ability to pay, and they function as a safety net for uninsured patients, many of whom use the ED for primary care services.

The new study used data from the California Department of Health Care Access and Information and the U.S. Census Bureau from January 1, 2011, to December 31, 2021.

In that time, California’s population grew by 4.2%, but the number of emergency departments in California fell from 339 to 326, while the number of hospital beds decreased by 2.5% (75,940 to 74,052).

“Our findings show what many health care workers already know to be true: The burden on emergency departments across the state of California has intensified over the last 10-15 years,” Hsia said.

“Becoming aware of these trends is the first step to improving emergency department care,” she said. “To efficiently and equitably address ED crowding and improve overall care, policy makers and health care administrators should work to increase ED capacity, while also making thoughtful decisions about where and how to best allocate resources.”

Co-authors from UCSF include Renee Y. Hsia, MD, MSc; Stefany Zagorov; Michael T. Savides; Madeline Feldmeier; and Newton Addo. Co-author from the National Bureau of Economic Research is Nandita Sarkar, Ph.D.