SUMMARIES FOR PATIENTS

Cost-Effective Management of Flu in Adults Older than 65 Years of Age

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The summary below is from the full report titled "Management of Influenza in Adults Older than 65 Years of Age: Cost-Effectiveness of Rapid Testing and Antiviral Therapy." It is in the 2 September 2003 issue of Annals of Internal Medicine (volume 139, pages 321-329). The authors are M.B. Rothberg, S. Bellantonio, and D.N. Rose.

What is the problem and what is known about it so far?

Influenza (flu) is a common illness caused by infection with influenza A or influenza B virus. It can keep people from their usual activities for days to weeks and can also lead to complications, such as pneumonia or death, especially in people who are elderly or who have underlying medical conditions. Yearly flu vaccine (flu shot) prevents influenza and its complications. Treating flu involves rest, fluids, and medications to decrease fever and aches. However, two classes of antiflu drugs, if taken shortly after symptoms begin, can shorten illness by 1 or 2 days and may decrease complications. Antiflu drugs include older, cheaper drugs (amantadine and rimantadine) and newer, more expensive drugs (oseltamivir and zanamivir). The newer drugs are active against both types of flu virus, while the older ones treat only influenza A virus. A 5-day supply costs about $2 to $20 for the older drugs and $48 to $60 for the newer drugs. The drugs have side effects (including nausea, dizziness, or confusion). There are tests for flu, but they are not available everywhere. This means that doctors often need to start treatment without first testing to be sure that the symptoms are from flu. Previous studies show that the costs of the antiflu medications are worth the benefits in younger adults, but the cost-effectiveness of flu testing or using antiflu drugs in people older than 65 years of age is unknown.

Why did the researchers do this particular study?

To evaluate the costs and benefits of flu testing or antiflu drugs in people older than 65 years of age with flu symptoms.

Who was studied?

Rather than studying actual patients, the researchers used computers to simulate a "virtual" group of people older than 65 years of age who had flu symptoms.

How was the study done?

Using published information and computers, the researchers estimated what might happen if people older than 65 years of age did (or did not) get a rapid test for influenza or antiflu drugs (amantadine or oseltamivir). They calculated how much it would cost for each year of life saved by avoiding flu symptoms and complications. The computer model looked separately at categories of people based on whether they had received vaccination or had medical conditions that increased their risk for complications.

What did the researchers find?

For patients older than 65 years of age who had not been vaccinated or who were at high risk for complications, using oseltamivir without first testing for flu was cost-effective. For vaccinated or low-risk patients, rapid testing followed by oseltamivir if test results were positive seemed to be the most cost-effective strategy. Amantadine was a reasonable alternative for people who cannot afford oseltamivir.

What were the limitations of the study?

This study was a computer simulation, so we cannot be sure what the results would be with actual people.

What are the implications of the study?

Doctors should consider oseltamivir to treat unvaccinated or high-risk patients older than 65 years of age who develop flu symptoms. For vaccinated people or those at low risk for complications, rapid testing before treatment with oseltamivir was the most cost-effective strategy. Amantadine without testing was a reasonable strategy for patients who cannot afford oseltamivir.