By Tatiana Sanchez, San Francisco Chronicle, December 1 2020

The number of California nursing homes with residents who became ill or died from the coronavirus more than doubled between May and August — the result of several risk factors that have made nursing homes particularly vulnerable to outbreaks, a report by the California Health Care Foundation revealed.
The foundation partnered with researchers from Cal Hospital Compare, IBM Watson Health and UCSF to study data from more than 800 nursing homes in May and August to better understand COVID-19 outbreaks in these facilities.
The report, released Tuesday, found that the size of the facilities and resident demographics played significant roles in infection and death rates, among other factors.
“The really surprising finding here was how these factors are changing and the risk in nursing homes is changing,” said Krisof Stremikis, director of market analysis and insight at the California Health Care Foundation. “We knew the pandemic was changing, and I certainly know this is a rapidly evolving situation. But now we have numbers and a statistically rigorous study that shows over time what matters.”
In May, an estimated 25% of the nursing homes studied had one or more residents with COVID-19 and 16% had at least one resident whose death was attributed to the virus, the report found. By August, 66% of the facilities had a COVID-19 case and 37% had at least one resident who died of the virus.
An estimated 29,232 nursing home residents across California had tested positive for the virus and 4,835 had died as of Nov. 15.
Four key factors have contributed to outbreaks inside nursing homes, according to the report. They include:
• Ownership: Early in the pandemic, case rates in for-profit nursing homes were up to six times higher than rates in nonprofit and government-run nursing homes. That included independent nursing homes and those under corporate ownership.
• Size: Larger nursing homes with more than 99 beds had case rates at least 55% higher than those with 68 or fewer beds in August. Case rates and deaths were consistently higher in larger nursing homes.
• Staff: Case rates were significantly higher in nursing homes that were low-staffed. As the pandemic progressed, nursing homes with an adequate number of registered nurses had greater protection against COVID-19 cases and deaths.
• Demographics: Cases were higher in nursing homes that had a higher percentage of Black or Latino residents. In May, nursing homes with more than 2% Black residents had COVID-19 case rates that were about three times higher than facilities with 2% or fewer Black residents. By August, nursing homes with more than 26% Latino residents had a 57% higher case rate than those with 6% or fewer Latino residents.
Researchers said they were most surprised by how the risk factors shifted throughout the pandemic. In the beginning, the ownership status of the nursing homes was most correlated with large numbers of cases and deaths. But by August, the biggest driver of infections and deaths in nursing homes was the demographics of the residents, including age and race.
“What was surprising was the level of change that happened over time,” said Dr. Bruce Spurlock, executive director of Cal Hospital Compare. “In the beginning, they were pretty much facility characteristics and the background (infection) rate in the county. Later they were more resident characteristics than they were facility characteristics. I think that was a big ‘aha’ for us. We didn’t expect that.”
Tatiana Sanchez is a San Francisco Chronicle staff writer. Email: tatiana.sanchez@sfchronicle.com Twitter: @TatianaYSanchez