Patients hospitalized with COVID-19 pneumonia have a higher risk of being diagnosed with dementia compared to those with other types of pneumonias, according to a new study from the University of Missouri.

Previous research has found links between COVID-19 and mild to severe cognitive impairments including dementia, particularly among those with long COVID.

This study, published earlier this month in peer-reviewed journal Open Forum Infectious Diseases, looked at 10,403 patients across the U.S. who were hospitalized for more than 24 hours with COVID-19 pneumonia, and found that roughly three per cent (312 patients) developed new-onset dementia over a median of 182 days after their recovery.

Typically, most people recover from pneumonia without lasting lung damage, according to Johns Hopkins Medicine, but pneumonia caused by COVID-19 can be severe, causing damage to the lungs that could leave patients with breathing difficulties for months after recovering from the disease.

After adjusting for a variety of factors including age, gender, ethnicity, hypertension, diabetes, cigarette and alcohol use, researchers found that the risks were “significantly higher” compared to those with pneumonia that was unrelated to a SARS-CoV-2 infection. The study also accounted for heart disease and other related issues due to the high rate of such risk factors among patients with a COVID-19 infection.

“The findings suggest a role for screening for cognitive deficits among COVID-19 survivors,” said lead researcher Dr. Adnan Qureshi, a professor of clinical neurology at the University of Missouri, in a statement.

“If there is evidence of impairment during screening and if the patient continues to report cognitive symptoms, a referral for comprehensive assessment may be necessary.”

The study found that the risk of new onset dementia was more common in patients over the age of 70, and primarily affected memory, self-regulation and the ability to perform everyday tasks, with language, awareness of time and location generally intact.

Researchers noted the data was pulled from Cerner Real-World Data, which means some risk factors for dementia such as level of education, socioeconomic status and physical activity could not be determined and were not accounted for in the analysis. The dataset meant researchers were also limited by their inability to quantify the severity of the pneumonia in the cases.

Qureshi said additional research could provide answers as to why COVID-19 pneumonia might increase dementia risk.