People age 50 and older are around 2-and-a-half times more likely to progress to a severe case of COVID-19. That's according to a new study that quantifies the risk factors that increase the odds that people infected with the coronavirus will develop a severe case of the disease.
The research, conducted by doctors in Shanghai, is a meta-analysis that examined data from 30 studies conducted between December 2019 and Feb. 19 involving 53,000 patients with confirmed cases of COVID-19. Most of the studies were conducted in Wuhan and other Chinese cities, though the analysis did include three studies involving patients from the United States, Australia and Korea.
Cases were considered to be severe if they had symptoms such as shortness of breath requiring 30 or more breaths per minutes (12 to 20 breaths a minute is considered normal for an adult); dangerously low levels of oxygen in the blood; and radiographic evidence of lung damage that had grown by 50% or more within a 24 to 48 hour period.
Being male increased the odds of progressing to severe illness by 1.3 times, while smoking made it a little over 1 to 2-and-a-half times more likely, the study found. Overall, patients with underlying medical conditions including hypertension, diabetes and cardiovascular disease were 2 to 3 times more likely to progress to severe illness.
Certain conditions raised those odds further, according to the study: For instance, people with chronic obstructive pulmonary disorder were anywhere from 2-and-a-half to nearly 11 times more likely to get severely ill. Kidney disease is also likely a big risk factor. While the research didn't pinpoint exactly how big that risk is, it suggested it's somewhere between 2- and 16-fold.
The researchers say the findings suggest doctors should give more attention and care to older patients with these underlying risk factors.
The researchers didn't explain why certain underlying conditions appeared to make patients more vulnerable to severe COVID-19 disease, though they did say that all the conditions cited above can involve an inflammatory response from the body. Patients with chronic kidney disease may be more vulnerable because their kidneys are already weak and damaged, and severe coronavirus infection can further damage those organs. It's possible such patients may have missed dialysis sessions or other regular medical care because they were under quarantine or because the local medical system had to shift resources to focus on the growing epidemic.
Other research has also suggested that people with hypertension may be at greater risk from COVID-19. However, neither that earlier study nor the current one made it clear whether the apparent elevated risk was among people whose condition was under control with medication or not, or whether they had other underlying health problems. "It does not make a lot of sense that if somebody is otherwise healthy and young and they have hypertension alone, that they should be at increased risk,"Dr. Mariell Jessup, chief science and medical officer at the American Heart Association, told NPR about the prior finding. However, she noted that so little is known about this coronavirus that everyone should take precautions.
Like a lot of research on this fast-moving pandemic, the new study was released prior to peer review on a preprint server to speed up the sharing of information among scientists.