Men over 50 with high blood pressure, heart disease or diabetes are most likely to die of Covid-19.

This is according to the records of 85 fatal cases in Wuhan, the Chinese city at the epicentre of the disease's early stages.

A study reported in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine is the biggest yet on coronavirus patient deaths.

Researchers from China and the US analysed the electronic health records of patients with Covid-19 who died despite treatment at Hanan Hospital and Wuhan Union Hospital between January 9 and February 15.

“The greatest number of deaths in our cohort were in males over 50 with non-communicable chronic diseases,” said the authors.

“We hope that this study conveys the seriousness of Covid-19 and emphasises the risk groups of males over 50 with chronic comorbid conditions including hypertension (high blood pressure), coronary heart disease and diabetes.”

The researchers analysed information on the patients' medical histories, exposures to coronavirus, additional chronic diseases they had, symptoms, laboratory findings, CAT scan results and clinical management.

The median age of the patients was 65.8, and 72.9% were men. Their most common symptoms were fever, shortness of breath and fatigue. Hypertension, diabetes and coronary heart disease were the most common comorbidities.

Four in five patients had very low counts of eosinophils — cells that are reduced in severe respiratory infections — on admission.

Complications included respiratory failure, shock, acute respiratory distress syndrome and cardiac arrhythmia. Most patients received antibiotics, antivirals and glucocorticoids (types of steroids).

The researchers noted: “The effectiveness of medications such as antivirals or immunosuppressive agents against Covid-19 is not completely known.

“Perhaps our most significant observation is that while respiratory symptoms may not develop until a week after presentation, once they do there can be a rapid decline, as indicated by the short duration between time of admission and death (6.35 days on average) in our study.”

They said abnormally low levels of eosinophils in the blood may indicate a poor prognosis, and the early onset of shortness of breath may be used as an observational symptom for Covid-19.

A combination of antimicrobial drugs (antivirals and antibiotics) did not significantly help these patients, most of whom died from multiple organ failure.

“Genetics may play a role in the response to the infection, and the course of the pandemic may change as the virus mutates as well,” the researchers said.

“Since this is a new pandemic that is constantly shifting, we think the medical community needs to keep an open mind as more and more studies are conducted.”