Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Jan;12(1):122-131.
doi: 10.1111/irv.12495. Epub 2018 Feb 15.

Estimated rates of influenza-associated outpatient visits during 2001-2010 in 6 US integrated healthcare delivery organizations

Hong Zhou  1 , William W Thompson  1 , Edward A Belongia  2 , Ashley Fowlkes  1 , Roger Baxter  3 , Steven J Jacobsen  4 , Michael L Jackson  5 , Jason M Glanz  6 , Allison L Naleway  7 , Derek C Ford  1 , Eric Weintraub  1 , David K Shay  1
Affiliations

Estimated rates of influenza-associated outpatient visits during 2001-2010 in 6 US integrated healthcare delivery organizations

Hong Zhou et al. Influenza Other Respir Viruses. 2018 Jan.

Abstract

Background: Population-based estimates of influenza-associated outpatient visits including both pandemic and interpandemic seasons are uncommon. Comparisons of such estimates with laboratory-confirmed rates of outpatient influenza are rare.

Objective: To estimate influenza-associated outpatient visits in 6 US integrated healthcare delivery organizations enrolling ~7.7 million persons.

Methods: Using negative binomial regression methods, we modeled rates of influenza-associated visits with ICD-9-CM-coded pneumonia or acute respiratory outpatient visits during 2001-10. These estimated counts were added to visits coded specifically for influenza to derive estimated rates. We compared these rates with those observed in 2 contemporaneous studies recording RT-PCR-confirmed influenza outpatient visits.

Results: Outpatient rates estimated with pneumonia visits were 39 (95% confidence interval [CI], 30-70) and 203 (95% CI, 180-240) per 10 000 person-years, respectively, for interpandemic and pandemic seasons. Corresponding rates estimated with respiratory visits were 185 (95% CI, 161-255) and 542 (95% CI, 441-823) per 10 000 person-years. During the pandemic, children aged 2-17 years had the largest increase in rates (when estimated with pneumonia visits, from 64 [95% CI, 50-121] to 381 [95% CI, 366-481]). Rates estimated with pneumonia visits were consistent with rates of RT-PCR-confirmed influenza visits during 4 of 5 seasons in 1 comparison study. In another, rates estimated with pneumonia visits during the pandemic for children and adults were consistent in timing, peak, and magnitude.

Conclusions: Estimated rates of influenza-associated outpatient visits were higher in children than adults during pre-pandemic and pandemic seasons. Rates estimated with pneumonia visits plus influenza-coded visits were similar to rates from studies using RT-PCR-confirmed influenza.

Keywords: electronic health records; human; influenza; office visits; statistical models.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Estimated rates of outpatient visits in 6 US healthcare delivery organizations (by age group) per 10 000 person‐years (left y‐axis) for influenza‐associated pneumonia and influenza (Panel A) and respiratory diseases (Panel B); and pandemic‐to‐pre‐pandemic rate ratios (right y‐axis): solid line, rate ratio; dashed line, pandemic rate; and dotted line, pre‐pandemic rate
Figure 2
Figure 2
Estimated weekly rates of outpatient visits per 10 000 persons for influenza‐associated pneumonia and influenza in 6 US healthcare delivery organizations participating in the Vaccine Safety Datalink (VSD) and for influenza‐associated influenza‐like illness outpatient visits from in the Influenza Incidence Surveillance Project (IISP), from October (week 40) 2009 through April (week 20) 2010
See this image and copyright information in PMC

References

    1. Centers for Disease Control and Prevention (CDC) . Estimates of deaths associated with seasonal influenza – United States, 1976‐2007. MMWR Morb Mortal Wkly Rep. 2010;59:1057‐1061. - PubMed
    1. Mullooly JP, Bridges CB, Thompson WW, et al. Influenza‐ and RSV‐associated hospitalizations among adults. Vaccine. 2007;25:846‐855. - PubMed
    1. Simonsen L, Clarke MJ, Stroup DF, Williamson GD, Arden NH, Cox NJ. A method for timely assessment of influenza‐associated mortality in the United States. Epidemiology. 1997;8:390‐395. - PubMed
    1. Simonsen L, Reichert TA, Viboud C, Blackwelder WC, Taylor RJ, Miller MA. Impact of influenza vaccination on seasonal mortality in the US elderly population. Arch Intern Med. 2005;165:265‐272. - PubMed
    1. Thompson WW, Shay DK, Weintraub E, et al. Influenza‐associated hospitalizations in the United States. JAMA. 2004;292:1333‐1340. - PubMed

LinkOut - more resources