COVID-19 deaths in nursing homes are well studied. But less is known about assisted-living residents, most of whom are over 80 years old and have multiple chronic illnesses.

A new research letter in the journal JAMA Network Open provides some clues.

"I think our findings really highlight the need to consider assisted living and its unique features when providing recommendations for preparedness and response activities to pandemics," said lead author Kali Thomas of Brown University School of Public Health in Rhode Island.

The nationwide study of more than 420,000 assisted-living residents finds the weekly death rate from all causes was 17% higher during COVID-19 than the year before — and nearly one-quarter higher in the 10 states with the greatest community spread, including Arizona.

Thomas said assisted-living communities were never intended to be medical settings.

"They likely did not have stockpiles of personal protective equipment, and they might not have the staff levels or the training that's required to adequately address the needs of residents during the pandemic."

The study looked at Medicare beneficiaries residing in licensed assisted-living settings with 25 or more beds in 49 states and Washington, DC. Researchers excluded Minnesota because it licenses agencies, not physical locations.

The research was also limited by an inability to identify cause of death, and by the exclusion of smaller assisted-living settings. 

"Future work is really needed to understand the experiences of assisted-living settings with fewer than 25 beds, which make up the minority of residents but the majority of actual settings, to understand their experiences. This is something we're continuing to explore," said Thomas.

Nevertheless, due to time lags in available data, the authors said their findings likely underestimate excess mortality during the pandemic.