People with high blood pressure may be more at risk of dying from COVID-19 once infected, according to a small study of coronavirus patients in China.

In a recent phone interview with Bloomberg, a top Chinese intensive-care doctor warned of hypertension, or high blood pressure, posing a "very dangerous" risk to COVID-19 patients. 

"From what I was told by other doctors and the data I can see myself among all the underlying diseases, hypertension is a key dangerous factor," said Du Bin, the director of the intensive-care unit in Peking Union Medical College Hospital.

Now, a small study may support Du Bin's claims.

Researchers studied 191 COVID-19 patients aged 18 and over from Jinyintan Hospital and Wuhan Pulmonary Hospital in China. Fifty-four of the sample size had died in hospital by January 31, while 137 had been discharged.

Of the 191 patients, 48 percent were found to have a comorbidity, or an underlying health condition. Of the 54 people who died, 67 percent had a comorbidity. 

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Hypertension was the most common comorbidity among the 191 patients, followed by diabetes and coronary heart disease.

Hypertension

Of the 191 patients, 58 had hypertension, or 30 percent. Of the 54 deceased, 26 had hypertension, or 48 percent. 

Diabetes

Of the 191 patients, 36 had diabetes, or 19 percent. Of the 54 deceased, 17 had diabetes, or 31 percent.

Coronary heart disease

Of the 191 patients, 15 had coronary heart disease, or 8 percent. Of the 54 deceased, 13 had coronary heart disease, or 24 percent.

The fourth comorbidity found in the test group was chronic obstructive lung disease, which affected 3 percent of all cases and 7 percent of fatal cases. This was followed by carcinoma, chronic kidney disease and "other", which affected 12 percent of all cases and 20 percent of all fatal cases.

Auckland-based microbiologist and infectious disease specialist Dr Siouxsie Wiles isn't surprised by the results, but warns that its localised test group may not be representative of all cases.

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"It's certainly clear that people with underlying health issues are more at risk if they develop COVID-19," Dr Wiles told Newshub.

"But only 191 cases were studied when there is now more than 118,000 worldwide - so the findings don't necessarily represent the entirety of cases on a global scale.

"The underlying health conditions could just be relevant to the nearby populations."

She also noted the lack of respiratory conditons, such as asthma and chronic bronchitis, which one may expect to see among the comorbidities.

Other statistics 

The study also found that 62 percent of the 191 analysed cases and 70 percent of the deceased were male. 

Six percent of the total cases were current smokers as well as 9 percent of the deceased.

Of the 191 cases, 35 percent were severe and 28 percent were critical. 

The Ministry of Health has been contacted for comment.

A Medical Officer of Health refused to comment until the information had been verified by the ministry.