SEOUL (June 11): South Korean doctors have found certain underlying conditions that may make some Covid-19 patients more severely affected by the disease, a professor at Yeungnam University Medical Center said yesterday.

The findings could help doctors identify and prioritise high-risk patients at an early stage of the respiratory disease caused by Covid-19, Ahn June-hong, professor of internal medicine, told Reuters.

Medical experts and epidemiologists are investigating risk factors for patients who develop severe cases of the disease, which has killed more than 400,000 globally since it first emerged late last year in China.

In a paper published by the Journal of Korean Medical Science on June 2, Ahn and other South Korean doctors wrote that diabetes, high body temperature, low oxygen saturation, and pre-existing cardiac injury were shown to be the prognostic factors for severe Covid-19 cases.

The team of doctors observed 110 Covid-19 patients at a hospital in Daegu, the epicentre of South Korea's outbreak, from Feb 19 to April 15.

Of the 110 patients in the Yeungnam University Medical Center, 23 developed a severe case of Covid-19.

Because such patients were significantly older than others, they were more likely to have diabetes and lower peripheral oxygen saturation, the paper said.

The Covid-19 patients with at least three of the four prognostic factors developed severe conditions, Ahn said.

"I believe using prognostic factors of severe Covid-19 patients will provide an opportunity for physicians to offer those risk-high patients with the best medical care from the early stage of the disease," he said.

As of midnight yesterday, South Korea reported 45 new cases, bringing the country's total to 11,947, with 276 deaths.