CLEVELAND, Ohio – As researchers learn more about the coronavirus, new – and seemingly contradictory – figures on the impact of the disease are clouding the outlook for Ohio.

Gov. Mike DeWine and Ohio Department of Health Director Dr. Amy Acton have said the state needs to double or even triple the total number of hospital beds available to be able to effectively respond to the virus at the peak of the outbreak in the state, which they predict will occur in late April. Anything less could leave Ohio’s hospital systems overwhelmed, they said. However, projections from the University of Washington’s Institute for Health Metrics and Evaluation on Monday showed the state in much better shape.

Statistical and epidemiological experts who spoke with cleveland.com said the fluidity of data surrounding the disease makes predicting exact numbers difficult. Even the IHME projections made a drastic shift from Monday to Tuesday. On Monday, the IMHE predicted Ohio would have enough hospital beds even under the model’s worst-case scenario. Updated predictions on Tuesday showed a small possibility the state will run out of beds if it does not increase capacity.

The primary issue that COVID-19 modelers face is a lack of available data. The U.S. lags behind some countries, like South Korea, in testing for the virus. Ohio officials have said they only have enough tests for the sickest people.

The lack of available data is likely forcing modelers to make educated assumptions as they create their formulas, said Helen E. Jenkins, a biostatistics professor at Boston University’s School of Public Health.

“We don’t have a good sense of some of these basic data,” Jenkins said. “And that’s why some of these models can differ, depending on what assumptions people are willing to make.”

The state has been releasing modeling on the pandemic curve, but thus far hasn’t released any predictive modeling on hospital bed capacity. DeWine spokesman Dan Tierney said Tuesday that the state has no current plans to do so.

Ohio State University’s Infectious Disease Institute, which is conducting modeling for the state, has declined to release the methodology for its modeling. A spokesman said they would release more information later this week.

One thing all the data have in common is a reliance on continuing social distancing practices to limit the chance of spreading the virus, Acton said.

“I can tell you we looked at worst-case scenario and best-case scenario,” Acton said during the state’s Tuesday coronavirus briefing. “I feel that our modelers at OSU are giving us the most realistic scenario of what we can deal with, and it’s based on that.”

Acton said Monday that her team hadn’t had a chance to delve into the IHME data. She said there are likely more complex factors involved than just relying on a predictive model based on the number of cases.

All the various models that predict the spread of the coronavirus in Ohio likely involve some common data sets, such as the number of confirmed cases and the state’s population of 11.7 million. Models could also factor in everything from the climate to the population density of an area, said Dr. Angelo DeLucia, an associate professor of molecular virology and cancer at the Northeast Ohio Medical University.

Other numbers used in the models, such as the mortality rate and the rate the coronavirus spreads from one person to another, could evolve over time and significantly change the final numbers, DeLucia said.

“Small percentage changes in some of these models could make dramatic impacts in terms of numbers,” DeLucia said.

A dramatic difference in the projections

While Acton has said Ohio needs to double or triple the number of beds in its hospitals, the IHME model suggests the state will get by at its current capacity.

The IHME modeling projects at different times during the peak of the outbreak, the state will need 5,609 total beds, 869 ICU beds and 695 invasive ventilators. That’s below the state’s current capacity of 14,290 beds and 1,238 ICU beds available. (A total number of ventilators was not given, though Northeast Ohio’s three largest hospitals alone have at least 1,000.)

Modeling is more complicated than just projections, said Scott Williams, a professor in population and quantitative health sciences at Case Western Reserve University. When researchers create models, they do so within a range of what is called a confidence level at 95%. In other words, the modelers predict a likely range of outcomes that will happen 95% of the time.

Williams agreed that the casino game roulette is an apt analogy. A person can bet the ball will land on either red or black at 1-to-1 odds. Hitting on any single number, however, is much more difficult.

“The point estimates are almost certainly going to be incorrect,” Williams said. “There are so many things that factor into that. Knowing the range of where you’re going to be is going to be more useful.”

The IHME model uses a litany of factors pulled from multiple countries, including the U.S., China, South Korea and Italy, to make its estimation. Among those variables are the probability of one person infecting others, death rate, age, implementation of social distancing policies and hospital bed capacity.

However, the data is constantly changing as new figures and science become available.

IHME Director Christopher Murray said in his pre-print for peer review any modeling based on evolving figures has its drawbacks. In a video news release about the model, Murray said he placed more emphasis on the death statistics because of the disparity in testing figures.

“But even in a setting with limited tests we have more faith in the death numbers because the tests that are available are preferentially used on the sickest patients,” Murray said. “So we model death over time, using statistical models and then we use those models to forecast the trajectory of death as a function of social distancing and social distancing policies. And then we take all the information that is available by age and sex, on utilization for bed days, ICU, ventilator use and model the number of bed days that are needed as indexed by number of deaths. So that is how we put all these pieces together.”

The ranges in the IHME modeling show the potential for a shortage in hospital and ICU beds, though to a smaller degree compared to what the state anticipates. The state could need as few as 873 beds or as many as 15,834 beds at peak. It could require as few as 109 or as many as 2,482 ICU beds, the model projects.

The likely range of outcomes is especially useful to experts and government officials as they develop plans to combat the virus, but it’s also more informative for the general public, Jenkins said.

“I think it’s really important that models always have a big range of possibilities in them. We shouldn’t be reporting just one number,” she said. “We have to remember that there’s a range of possibilities, and a more responsible thing is to be reporting that full range as the likely outcome.”

J.B. Silvers, professor of health care finance at Case Western Reserve University’s Weatherhead School of Management and vice chairman of MetroHealth’s board of trustees, said increasing bed capacity isn’t relegated to just manufacturing more beds.

Hospitals may have beds that currently aren’t staffed or can reconfigure whole units to increase the number available, Silvers said. Hotels, dorms and convention centers are also usable for housing people who need less care, potentially increasing capacity.

Projections could change as cases increase

The need for more beds rises as the number of confirmed cases increases, Acton said. The current OSU modeling shows anywhere from 6,000 and 10,000 new cases per day during the peak, which could hit between late-April and mid-May.

Of those cases, only a percentage will gain admission to the hospital and an even smaller percentage in the intensive care unit, Acton said.

The average length of stay in a hospital for any condition is three days, but for coronavirus, it can be up to 20 days, Acton said. It’s as those cases pile up that hospital bed capacity becomes an issue.

“You can’t just look at who might be sick or the number of cases on a day,” Acton said. “They’re piling up on each other logarithmically. So those beds aren’t emptying out. That’s all part of the complicated calculations that I think some of our modelers are trying to take into account.”

It’s here where the OSU and IHME models appear to diverge.

Lack of data makes COVID-19 modeling difficult

Predictive modeling is especially tricky for the coronavirus because it is so new, Williams said. Models vary based on different variables, and the assumptions put into them, such as population density and infectivity.

“They have to be laden with assumptions,” Williams said. “The people who do this, they do it for a living and they probably make reasonable assumptions most of the time. But it’s also dependent on them knowing about the infectious agent, and in this case, we don’t know much about it because it is new to humans. That kind of raises the issue of do you really know what’s going on.”

Experts can use models for tracking other viruses, such as SARS or the common flu, as a starting point to predict the spread of COVID-19. Even still, there are so many unknowns about the novel coronavirus that it’s difficult to forecast, Jenkins said.

“There are lots of characteristics about this new virus which are very different from other pathogens,” Jenkins said. “So we’re really having to think about what is different about this virus, and how we can adapt those models.”

It’s also difficult to quantify the effect of steps taken to mitigate the spread of the virus, such as social distancing, Jenkins said.

“I think that it’s very hard to predict human behavior at this point,” Jenkins said. “I think a positive message from that, though, is that individuals can do a lot to bring that final number down toward the bottom of the range that’s being predicted.”

Tierney, the governor’s spokesman, said DeWine and Acton were taking the various models into account in their response.

“The bottom line is that most modeling indicates that COVID-19 will have a significant impact on Ohio, and we are preparing to ensure all Ohioans are able to receive the care they need,” Tierney said.

As for why DeWine may be using the high-end projections, Silvers said the answer was simple.

“If you look at the confidence level or some range, if you do too much, you might get criticized for wasting money,” Silvers said. “If you do too little, you’re dead. Literally.”

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