According to a recent Centers for Disease Control and Prevention (CDC) study, adults with underlying medical conditions (UMCs) who got the flu were at greater risk for hospitalization, compared to those without such conditions.  Rates of flu-related hospitalizations were especially high for individuals with congestive heart failure (CHF), followed by COPD and blood disorders. 

The authors examined several underlying conditions in the study: asthma, blood disorders, cerebrovascular disease, diabetes, chronic obstructive pulmonary disease (COPD), ischemic heart disease, liver disease, neurological or musculoskeletal disorders, chronic kidney disease, rheumatologic or autoimmune conditions, and congestive heart failure.  The rate of hospitalization was higher for those patients who had more UMCs.

The retrospective study involved adult members of two health systems ages 18 years or older with prior health care utilization. The authors estimated influenza-associated hospitalization rates by type and number of underlying medical conditions. They defined hospitalizations using discharge diagnoses or laboratory confirmation. The authors determined that among 870,888 patients, 1,403 were hospitalized with influenza at least once a season across four seasons. 

“The effect of UMCs on influenza-associated hospitalizations was higher when not mediated by vaccination status,” the authors observed, adding that for patients with four or more UMCs, compared to no underlying conditions, the rates were about 60% higher.” In conclusion, they said, “Among those with varying types and number of UMCs, if vaccination prevalence had been lower than observed, influenza-associated hospitalization rates would have been higher.”

This study’s results support the importance of preventive care, as well as annual flu vaccines, to help reduce influenza-related hospitalizations, especially for those  who have or are at risk for underlying conditions.