People age 50 and older are 2.6 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 1.7 times more likely. Overall, patients with underlying medical conditions including hypertension, diabetes and cardiovascular disease were 2.6 times more likely to progress to severe illness.

Certain conditions raised those odds further: For instance, people with chronic obstructive pulmonary disorder were six times more likely to get severely ill, while those with chronic kidney disease were five times more likely.

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 made 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.

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