Coronavirus fatality risk factors revealed

A study of patients hospitalised in Wuhan reveals the risk factors for dying of a COVID-19 infection

Older people, those with pre-existing signs of sepsis and people having blood clotting issues are most at risk of dying from COVID-19, a study of those hospitalised in Wuhan reveals.

Dr Zhibo Liu, from Jinyintan Hospital in China, and his colleagues, undertook a retrospective study of the medical records of 191 adults with COVID-19 who were admitted to Jinyintan Hospital and Wuhan Pulmonary Hospital in Wuhan, the heart of the outbreak in China.

Among these patients, 137 were discharged and 54 died in hospital.

“Poorer outcomes in older people may be due, in part, to the age-related weakening of the immune system and increased inflammation that could promote viral replication and more prolonged responses to inflammation, causing lasting damage to the heart brain and other organs,” Dr Liu said in a statement.

Those who died had an average age of 69 years, compared with 52 years among the survivors.

They were also more likely to have underlying diseases such as high blood pressure, diabetes or coronary heart disease.

However, infectious diseases expert Professor Allen Cheng cautioned that the study sample was small and there were likely to be gaps in the medical records.

“I’m not sure to what degree those diseases are just diseases that older people, have rather than being true risk factors,” the professor of infectious diseases epidemiology at Monash University said.

“Take hypertension, for example. It’s hard to see why high blood pressure might be a risk factor for mortality,” he says. “You can dream up something, but you’d still have to test those things a bit more carefully.”

Professor Cheng said some had suggested the link to high blood pressure might be because the virus attaches to a particular receptor in the lungs, known as the ACE2 receptor, and medications used for blood pressure can influence that receptor. But more testing was needed to understand whether this was the case.

There was also no mention of obesity or smoking either, which were important in other diseases, he said. This might have been due to poor recording in the medical records.

One surprise finding was that patients who survived COVID-19 could shed the virus for as long as 37 days. The median duration of shedding was 20 days, with the shortest time being eight days.

Dr Liu and colleagues were able to detect the virus up until the patient’s death.

“The extended viral shedding noted in our study has important implications for guiding decisions around isolation precautions and antiviral treatment in patients with confirmed COVID-19 infection,” study co-author Professor Bin Cao, from the China-Japan Friendship Hospital and Capital Medical University, China, said in a statement.

However, it was important not to confuse viral shedding time with self-isolation recommendations for those potentially exposed to COVID-19 who had no symptoms, he said. That guidance was based on the incubation time of the virus.

These results suggest that the more severe the illness, the longer the duration of shedding may last. 

The study also found that fever lasted an average of 12 days in survivors, and around half had a cough when discharged. Shortness of breath resolved in around 13 days in survivors but stayed until death in non-survivors.

Factors such as lymphopenia, leucocytosis, elevated ALT, lactate dehydrogenase, high-sensitivity cardiac troponin I, creatine kinase, serum ferritin, IL-6, prothrombin time, creatinine and procalcitonin were also linked to an increased risk of death.

Professor Cheng said it was important to concentrate on elderly patients, to give them very specific advice about what to look for and do if they became unwell, and to consider calling them in the days following a diagnosis to check if it had progressed.

“Clearly they are a very high-risk group,” he said.

But it might also be worth checking on younger patients with health conditions, such as diabetes, COPD or cardiac failure, to ensure their care was optimised.

“Often patients are a little bit on the borderline, and you might want to see them a little bit early to make sure they are okay before anything happens, and to make sure they can get medications in advance so they don’t have to see you for a little while,” Professor Cheng said.

The Lancet; https://doi.org/10.1016/S0140-6736(20)30566-3