During 2017–2018, 37.2% of ED visits for influenza and pneumonia by adults aged 18 years or older resulted in a hospital admission.
The percentage increased with age from 14.4% for adults aged 18–54 years to 46.9% for adults aged 55–74 years and 69.7% for adults aged 75 years or older.
Source: National Center for Health Statistics. National Hospital Ambulatory Medical Care Survey, 2017–2018. https://www.cdc.gov/nchs/ahcd/ ahcd_questionnaires.htm.