Study characterizes long-COVID symptoms in hospitalized and non-hospitalized COVID-19 patients

In an article published in the journal Digital Medicine, scientists have provided a detailed overview of the long-term symptoms experienced by coronavirus disease 2019 (COVID-19) patients after initial primary infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Background

A considerable proportion of COVID-19 patients have been found to experience a range of symptoms even after the resolution of the initial SARS-CoV-2 infection. This condition is commonly known as long-COVID. The most common long-COVID symptoms are fatigue, breathing difficulty, pain, lack of concentration, and depression. Even patients with mild initial infection can experience long-COVID symptoms for weeks to months.

Despite a high prevalence of long-COVID, not enough information is available about the variety of symptoms that may arise from primary SARS-CoV-2 infection. An in-depth understanding of long-COVID symptoms is particularly needed to inform public health authorities, healthcare professionals, and patients about the risk of long-lasting post-infection consequences.

In the current study, the scientists have evaluated the risk and prevalence of long-COVID symptoms among hospitalized and non-hospitalized patients with COVID-19 in multi-national settings.

Study design

The study analysis was conducted on the electronic health record data collected from 277 international hospitals. The study population included 414,602 COVID-19 patients and 2.3 million control patients without COVID-19. Both inpatient (hospitalized) and outpatient cases (non-hospitalized) were considered for the analysis.

More than 221 million diagnosis codes were included to identify new-onset conditions that were prevalent among COVID-19 patients during the post-infection period. An acute infection period was defined as within 29 days of infection onset. A mid-stage post-acute period was defined as 30 – 89 days after initial infection. A late-stage post-acute period was defined as over 90 days after initial infection.

Study population

A total of 75,232 hospitalized and 339,370 non-hospitalized COVID-19 patients were included in the analysis. Similarly, the numbers of inpatient and outpatient control participants were 505,055 and 1,825,473, respectively.

Baseline prevalence of health conditions

Inpatient cases

A higher baseline prevalence of diabetes, obesity, chronic kidney disease, cardiopulmonary disease, and gastroesophageal disease was observed among hospitalized COVID-19 patients compared to among hospitalized control patients.

During acute infection, hospitalized COVID-19 patients had the highest incidence of pneumonia, respiratory distress, acute kidney injury, hypertension, malaise, and fatigue. Compared to hospitalized controls, hospitalized COVID-19 patients had a higher incidence of viral pneumonia, respiratory abnormalities, malaise, fatigue, acute kidney injury, and hypovolemia.

Outpatient cases

A higher prevalence of gastroesophageal disease, obesity, and depression was observed among non-hospitalized COVID-19 patients compared to among non-hospitalized controls.

During acute infection, non-hospitalized COVID-19 patients had the highest incidence of cough, viral infection, respiratory distress, fever, and viral pneumonia. Compared to non-hospitalized controls, non-hospitalized COVID-19 patients had a higher incidence of viral infection, viral pneumonia, cough, respiratory distress, acute upper respiratory infections, fever, malaise, and fatigue.  

Long-COVID symptoms in hospitalized COVID-19 patients

A significantly higher risk of heart failure, pneumonia, respiratory distress, cough, malaise, fatigue, and cognitive dysfunction was observed among hospitalized COVID-19 patients during the mid-stage post-acute period compared to that among hospitalized controls.

During the late-stage post-acute period, hospitalized COVID-19 patients showed an increased risk of angina pectoris (chest pain due to coronary heart disease).

Long-COVID symptoms in non-hospitalized COVID-19 patients

A significantly higher risk of pulmonary embolism and infarction, pneumonia, venous embolism and thrombosis, atrial fibrillation, hypertension, diabetes, vitamin D deficiency, dementia, amnesia, malaise, and fatigue was observed among non-hospitalized COVID-19 patients during the mid-stage post-acute period compared to that among non-hospitalized controls.   

During the late-stage post-acute period, non-hospitalized COVID-19 patients showed an increased risk of skin ulcers, diabetes, vitamin D deficiency, dementia, respiratory distress, loss of taste and smell sensation, and inflammatory neuropathy.

Overall, a gradual decline in the incidence of cardiovascular and pulmonary conditions over time was observed among hospitalized COVID-19 patients. In contrast, an induction in the incidence of cardiovascular, digestive, and metabolic conditions was observed among non-hospitalized COVID-19 patients.

Study significance

The study compares the incidence of long-COVID-19 among hospitalized and non-hospitalized COVID-19 patients at different stages of post-acute infection. As mentioned by the scientists, the study findings might help develop evidence-based evaluation and management guidelines.  

Written by

Dr. Sanchari Sinha Dutta

Dr. Sanchari Sinha Dutta is a science communicator who believes in spreading the power of science in every corner of the world. She has a Bachelor of Science (B.Sc.) degree and a Master's of Science (M.Sc.) in biology and human physiology. Following her Master's degree, Sanchari went on to study a Ph.D. in human physiology. She has authored more than 10 original research articles, all of which have been published in world renowned international journals.