Frequency and Factors Associated With Hospital Readmissions Due to Influenza

A hospital patient
A hospital patient
Hospitalization due to influenza leads to a high likelihood of readmission within 30 days and 1 year with cardiovascular, respiratory, and infectious etiologies being the most common.

Hospitalization due to influenza leads to a high likelihood of readmission within 30 days and 1 year most commonly as a result of cardiovascular, respiratory, and infectious processes, according to results published in the Journal of Infectious Diseases.

In this retrospective study, researchers analyzed data from the Tennessee Emerging Infections Program Influenza Surveillance system from 2006 to 2016, as well as the concurrent Tennessee Hospital Discharge Data System to better understand the frequency and factors associated with hospital readmission after an admission with laboratory-confirmed influenza.

Of the 2897 patients included in the study, 409 (14%) and 1364 (47%) had1 hospital readmission within 30 days and 1 year of the influenza hospitalization, respectively. Multiple readmissions occurred in 740 patients (54%). In contrast, the percentage of patients readmitted for any cause was 8% and 29% within 30 days and 1 year, respectively.

Compared with patients who did not experience readmissions, those who did were older, were predominantly women, and had more comorbidities. Smoking status and race were not statistically significant between patients in these 2 groups. Patients who were readmitted were also more likely to have been vaccinated than those who were not (48% vs 37%; P <.01). Researchers noted that further studies into influenza vaccination and hospital readmission are needed, as influenza vaccination was not associated with a lower risk for readmission.

Of the patients readmitted within 30 days, 28% had an infectious disease diagnosis, 14% had a pulmonary disease diagnosis, and 11% had a cardiovascular diagnosis as their principal diagnosis. Of patients aged > 65 years, 27% of readmissions were due to a primary infectious diseases diagnosis, 17% cardiovascular disease diagnosis, and 14% a pulmonary disease diagnosis within 1 year.

Pneumonia, acute chronic obstructive pulmonary disease/asthma exacerbation, septicemia, acute respiratory failure, and acute renal failure were the most frequent principal diagnosis within 30 days. Similarly, acute chronic obstructive pulmonary disease/asthma exacerbation, septicemia, and pneumonia were the most frequent within 1 year.

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Multivariable analysis of hospital readmission within 1 year showed the following preexisting conditions to be associated with increased risk for admission:

  • Cardiovascular disease (odds ratio [OR], 1.6; 95% CI, 1.30-1.98)
  • Lung disease (OR, 1.6; 95% CI, 1.34-1.86)
  • Kidney disease (OR, 1.7; 95% CI, 1.34-2.15)
  • Diabetes (OR, 1.3; 95% CI, 1.05-1.56)
  • Immunosuppression (OR, 1.6; 95% CI, 1.27-2.10)
  • Hemoglobinopathy (OR, 2.4; 95% CI 1.44-4.02)
  • Liver disease (OR, 2.1, 95% CI, 1.23-3.41)

“Patient comorbidities could be an important link to understanding these readmissions,” noted the researchers. “Further studies are needed to elucidate conditions that could be targeted to decrease readmissions and to determine the role of vaccination in prevention of readmission,” they concluded.

Disclosure: H. Keipp Talbot, MD MPH, and William Schaffner, MD, declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of their disclosures.


Dobrzynski DM, Ndi DN, Zhu Y, Markus T, Schaffner W, Talbot HK. Hospital readmissions following laboratory-confirmed influenza hospitalization [published online March 17, 2020]. J Infect Dis. doi:10.1093/infdis/jiaa117