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Older hospitalized patients less likely to undergo provider-ordered influenza tests
When compared with younger patients, adults older than 65 years hospitalized for nonlocalizing fever or acute respiratory illness were less likely to undergo provider-ordered influenza tests, according to findings published in the Journal of the American Geriatrics Society.
“A better understanding of the factors involved in provider-ordered testing is needed to determine the barriers to early identification and treatment of infection,” Lauren M. Hartman MD, of the department of medicine at Vanderbilt University School of Medicine, and colleagues wrote.
Researchers conducted their study on 1,422 patients aged 18 years and older with nonlocalizing fever or acute respiratory illness at four hospitals in Tennessee.
Hartman and colleagues found that 28% of patients had provider-ordered influenza testing. Those who underwent tests were younger than those who were not tested (mean age, 58 ± 18 years vs. 66 ± 15 years; P < .001) and more likely to have influenza-like illness (71% vs. 49%; P < .001).
Researchers also wrote that younger age and having an influenza-like illness were independent predictors of provider-ordered testing. In the 136 patients with influenza validated by reverse-transcriptase polymerase chain reaction tests, only influenza-like illness was a significant predictor of provider-ordered testing (adjusted OR = 3.43; 95% CI, 1.22-9.7).
“No single factor accounts for decreased provider-ordered testing in [the older adult] population, though differences in presentation including less influenza-like illness, attenuation of symptoms by vaccination, and higher burden of underlying cardiac and pulmonary disease may impact the decision of the provider to perform influenza testing,” Hartman and colleagues wrote. “Further strategies are needed to increase clinician understanding of the challenges in clinically identifying influenza in older adults, as well as the limitations of diagnostic tests, to better diagnose and treat cases of influenza in this vulnerable population.” – by Janel Miller
Disclosures: Hartman reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.
Perspective
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I’m not surprised by the findings of this study. We’ve only gradually begun to appreciate the amount of hospitalized illness in the winter that is due to influenza. This is in part because, until the 2009 pandemic, there was very little testing done, especially among adults hospitalized with respiratory infections, even if these infections occurred during the flu season.
Influenza testing is still not done in a lot of places in the United States. These tests are pretty much confined to the referral hospitals, and so a lot of influenza is missed. Part of the reason we are missing so many cases is due to the underappreciation of value of using antivirals to treat influenza. One of the reasons for such little testing is that antivirals were not considered to make much of a difference in patient management. But we do have antivirals and they do work and are effective in shortening illness and preventing complications. But for some reason, there continues to be an underappreciation of antivirals’ value.
Primary care physicians typically only have access to tests that are good at specificity but lack in sensitivity. As a result, sometimes these tests show up negative for influenza, but the patient really did have the flu. If there is more serious illness, then the specimen can be sent off to a lab that can do the polymerase chain reaction (PCR) test, which is the most sensitive and specific test we have. But few PCPs have access to PCR because they are expensive and the results are not obtained as quickly as other tests. We have recommended for a number of years, because fever and cough are so common with influenza, especially in the influenza season, if someone is coughing, there is about a 65% to 75% chance that the person really has influenza and, thus, a medically based decision needs to be made if that person ought to be treated with antivirals.
We are in the middle of a severe influenza season where we do have a greater likelihood that cases of mild influenza will become more severe. And though it is true that very often people only come to the doctor if they haven’t gotten better over a period of time, it is also true that antivirals do not work as well in these later diagnoses. The message to both the PCP and the patient needs to be, if the symptoms resemble the flu, assume the ailment is the flu, especially if you are concerned about preventing complications. This is particularly relevant in those populations at higher risk, such as older patients, those with underlying conditions and very young children.