Rise in flu cases means more hospital patients, but also more costs

The Centers for Disease Control and Prevention this week warned healthcare providers that they're seeing an uptick in influenza cases in a strain that's normally associated with increased hospitalizations. But those higher patient volumes could be paired with higher costs.

The latest CDC figures show that 36 states have reported widespread flu activity, up from 23 during the week of Dec. 16.

The agency issued a health alert on Wednesday warning clinicians that a majority of the flu cases reported so far have been of the H3N2 strain of the virus, which is usually associated with a higher number of hospital admissions and flu-related deaths. That's partially because flu vaccines tend to be less effective against H3N2 compared to other strains of the virus.

The CDC has reported a large spike in flu hospitalizations in recent weeks among adults age 65 and older, which jumped from 13.7 out of every 100,000 hospitalizations on Dec. 2 to 35.8 per 100,000 as of Dec. 23. A total of 2,485 laboratory-confirmed influenza-associated hospitalizations were reported between Oct. 1 and Dec. 23, according to the agency, with more than 87% of those cases involving H3N2.

The flu can be costly to both providers and patients. Between 5% and 20% of the U.S. population get the flu each year at a cost of $10.4 billion a year in direct medical expenses, according to the CDC.

From a financial perspective, the increase in hospitalizations and emergency department foot traffic would appear to benefit hospitals, since the flu usually requires inexpensive treatment such as rest, fluids and antiviral medications.

But the flu's impact on a hospital's bottom line can be as unpredictable as the virus itself.

During the 2009 H1N1 pandemic, the average cost of a patient hospital stay was $11,000 compared to $8,500 during the 2008 influenza season, according to the Agency for Healthcare Research and Quality.

A large, sudden influx of cases can often overwhelm a hospital's capacity, putting a strain on resources that can be diverted from patients being treated for other conditions.

The flu season's financial impact on hospitals is largely determined by the strain that's most predominant. Some flu strains, like H3N2, tend to more heavily affect older adults, who may have other health conditions that complicate treatment and make it more expensive.

"If they get sick they tend to be in the hospital longer and more likely to be in the intensive-care unit," said Dr. John Segreti, an infectious disease specialist at Rush University Medical Center in Chicago.

Since 2009, Rush has conducted year-round planning for every flu season that he said has helped mitigate its burden, Segreti said. The hospital has an incident command center on standby in case it's suddenly overrun with flu cases.

Rush began seeing an uptick in flu-related hospital admissions a few weeks ago, according to Segreti, with older adults making up the majority of those cases.

"This is the more difficult type of flu season," he said.