637. Late diagnosis of influenza in adult patients during the seasonal outbreak
Session: Poster Abstract Session: Oh, Those Pesky Viruses!
Thursday, October 27, 2016
Room: Poster Hall
Background: Clinical courses and outcomes of influenza patients have been known to be affected by neuraminidase inhibitor (NAI) therapy. However, during a seasonal influenza outbreak, appropriate utilization of NAIs is usually dependent on the early diagnosis (ED), mainly from the expanding use of viral diagnostic tests such as the rapid influenza antigen test or real-time PCR test in clinical practice. We investigated the clinical impact of late diagnosis (LD) in adults with seasonal influenza.

Methods: Clinical data were investigated in 1,405 adults who had visited four tertiary care centers, received a diagnostic test for influenza, and had a positive test results during 3 months of the 2013-2014 flu season. A patient was regarded to receive ED or LD if he (or she) received an influenza test respectively on 0–1 or 4–7 days after the onset of symptoms. Early or late NAI therapy was defined as the administration of NAI on ≤2 days or >2 days after the onset of symptoms, respectively.

Results: Nearly a half of the study patients received ED (661, 47.0%), and 13.5% (n = 190) received LD. Whereas patients with LD had initial symptoms of cough (87.4% vs. 80.0%, p = 0.02), sputum production (63.7% vs. 51.1%, p = 0.002), and dyspnea (14.7% vs. 5.6%, p <0.001), pneumonia (16.3% vs. 4.2%, p <0.001), antibiotic therapy (25.3% vs. 18.0%, p = 0.03), hospitalization (28.9% vs. 19.1%, p = 0.003), and admission to intensive care unit (3.7% vs. 0.9%, p = 0.01) more commonly than those with ED, the former received NAI therapy (82.1% vs. 90.0%, p = 0.003) or early NAI therapy (2.6% vs. 99.0%, p <0.001) less commonly than the latter. Pneumonia was associated with LD (adjusted odds ratio for pneumonia = 2.65, 95% confidence interval = 1.26 – 5.59, p = 0.01), rather than with late NAI therapy (aOR for pneumonia = 1.42, 95% CI = 0.73 – 2.75, p = 0.31). Among the baseline characteristics, age of ≥50 years (adjusted odds ratio = 1.49, 95% confidence interval = 1.05 – 2.90, p <0.001), influenza B infection (aOR = 2.01, 95% CI = 1.52 – 2.90, p <0.001), and diagnosis using the PCR test (aOR = 2.18, 95% CI = 1.34 – 3.56, p= 0.002) were associated with LD.

Conclusion: LD was associated with inappropriate antiviral therapy and complicated initial clinical features in adult patients with seasonal influenza. Considering that the appropriate management of influenza may be dependent on the early diagnosis more commonly than before, diagnosis of influenza should be made early, especially for older adults.

Seong-Ho Choi, MD1, Mi Suk Lee, MD, PhD2, Ki-Ho Park, MD2, Tark Kim, MD3, Yee Gyung Kwak, MD4 and Jin-Won Chung, MD1, (1)Department of Internal Medicine, Chung-Ang University Medical Center, Seoul, South Korea, (2)Division of Infectious Diseases, Department of Internal Medicine, Kyung Hee University Hospital, Seoul, South Korea, (3)Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea, (4)Inje University, Goyang, South Korea

Disclosures:

S. H. Choi, None

M. S. Lee, None

K. H. Park, None

T. Kim, None

Y. G. Kwak, None

J. W. Chung, None

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