Since the start of the SARS-CoV-2 pandemic, researchers have analyzed the data of over 70,000 people with COVID-19 in the U.S. to identify the most common complications of the disease and its aftermath. In a December 2020 study, published in the Canadian Medical Association Journal, scientists reviewed all available reports of COVID-19 complications to determine which had the strongest associations and posed the highest risks.* 

What they did

The study was a collaborative effort between scientists from:

• Jacobs School of Medicine & Biological Sciences at the University at Buffalo in New York
• New York-based health tech company Aetion, Inc.
• Department of Medicine at the University of Toronto in Canada
• Philadelphia-based health technology company HealthVerity, Inc.

The research team analyzed the anonymous health claims data of 70,288 people who received COVID-19 diagnoses between March 1 and April 30, 2020. They divided the information into categories by healthcare setting, of which:

• 46.6% were outpatients.
• 53.4% were admitted to the hospital.
• Of those in the hospital, 4.7% were admitted to the intensive care unit (ICU).

The median age was 65 years, and 55.8% of the patients were female. The researchers defined a “hazard period” (seven (7) days before to 30 days after the diagnosis) and a “baseline period” (120 days before to 30 days before the diagnosis). The baseline period was used to eliminate any pre-existing chronic conditions.

What they found

After analyzing all 1,724 diagnosis codes, the team identified 69 of them as being significantly associated with COVID-19. These relative odds indicate that those 69 conditions can likely be attributed to COVID-19 or its treatment.

The study confirmed that the previously identified conditions most strongly associated with COVID-19 are:

• • Respiratory conditions, such as pneumonia, acute respiratory distress syndrome (ARDS), acute lower respiratory infection, respiratory failure, and pneumothorax (collapsed lung)
  • Circulatory conditions, such as cardiac arrest and acute myocarditis (inflammation of heart wall)
  • Hematologic disorders (related to the blood)
  • Kidney disorders
  • Interference with senses of smell and taste

The most common (highest risk) conditions included:

• Pneumonia (27.6% of all study patients and 81% of those in ICU)
• Respiratory failure (22.6% of all and 75.3% in ICU)
• Acute kidney failure (11.8% of all and 50.7% in ICU)
• Other sepsis (10.4% of all and 54.1% in ICU)

Complications that were both highly associated with COVID-19 and high risk included:

• Viral pneumonia 
• Respiratory failure 
• Sepsis (when the body’s infection-fighting process turns toxic)
• Acute kidney failure
• ARDS

What it means

By understanding the likelihood of complications, patients, providers, and policymakers can better treat, educate, and prepare everyone affected by COVID-19.

The study authors do caution, however, that the study may have limitations, such as:

• Milder conditions, even if common, are less likely to be recorded in health claims.
• The study focused on newly diagnosed conditions, so it does not reflect the risk of worsening pre-existing conditions.
• Some conditions may have been misclassified or diagnosis codes used inconsistently.
• Certain complications may have resulted from the treatment of COVID-19, not from the disease itself.

*Vince, M. (2020, Dec. 25). Analysis of Patient Data Reveals Most Common Complications of COVID-19. Medical News Today. https://www.medicalnewstoday.com/articles/analysis-of-patient-data-reveals-most-common-complications-of-covid-19 

Much about the novel coronavirus, i.e., COVID-19, is still not fully understood. As research progresses and our knowledge of the virus increases, information can change rapidly. We strive to update all of our articles as quickly as possible, but there may occasionally be some lag between scientific developments and our revisions.